摘要:

J. CHEM. SOC. PERKIN TRANS. II 1987 s1 Tables of Bond Lengths determined by X-Ray and Neutron Diffraction. Part I. Bond Lengths in Organic Compounds Frank H. Allen,” Olga Kennard, and David G. Watson Cambridge Crystallographic Data Centre, University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW Lee Brammer and A. Guy OrpenSchool of Chemistry, University of Bristol, Cantock’s Close Bristol BS8 1 TS Robin Taylor I.C.I. Plant Protection Division, Jealott’s Hill Research Station, Bracknell, Berkshire RG 12 6EY The average lengths of bonds involving the elements H, B, C, N, 0, F, Si, P, S, CI, As, Se, Br, Te, and I in organic compounds are reported. The determination of molecular geometry is of vital importance to our understanding of chemical structure and bonding.The majority of experimental data have come from X-ray and neutron diffraction, microwave spectroscopy and electron diffraction. Over the years compilations of results from these techniques have appeared sporadically. The first major compil- ation was Chemical Society Special Publication No. 11: ‘Tables of Interatomic Distances and Configuration in Molecules and Ions’. This volume summarized results obtained by diffraction and spectroscopic methods prior to 1956; a supplementary volume2 extended this coverage to 1959. Summary tables of bond lengths between carbon and other elements were also published in Volume I11 of ‘International Tables for X-Ray Cry~tallography’.~Some years later the Cambridge Crystallo- graphic Data Centre4 produced an atlas-style compendium of all organic, organometallic, and metal complex crystal structures published in the period 1960-1965. More recently a survey of geometries determined by spectroscopic methods has extended coverage in this area to mid-1977.The production of further comprehensive compendia of X-ray and neutron diffraction results has been precluded by the steep rise in the number of published crystal structures, as illustrated by Figure 1. Printed compilations have been effectively superseded by computerized databases. In particular the Cambridge Structural Database (CSD) now contains biblio- graphic, chemical and numerical results for ca. 55 000 organo-carbon crystal structures. This machine-readable file fulfils the function of a comprehensive structure-by-structure com- pendium of molecular geometries.However the amount of data now held in CSD is so large that there is also a need for concise, printed tabulations of average molecular dimensions. The only tables of average geometry in general use are those contained in the Chemical Society Special Publications ‘v2 of 1958 and 1965, which list mean bond lengths for a variety of atom pairs and functional groups. Since these early tables were based on data obtained before 1960, we have used CSD to prepare a new table of average bond lengths in organic compounds. The Table given here specificially lists average lengths for bonds involving the elements H, B, C, N, 0,F, Si, P, S, C1, As, Se, Br, Te, and I.Mean values are presented for 682 different bond types involving these elements. Average bond lengths in organometallic compounds and metal complexes will be presented in a later paper. Methodology Selection of Crystallographic Data.-All results given in the Table are based on X-ray and neutron diffraction results 5000 4000 3 000 2 000 1000 year 1965 1970 1975 1980 1985 Figure 1. Growth of the Cambridge Structural Database 1965-1985 as no. of entries (nent) published in a given year retrieved from the September 1985 version of CSD. Neutron diffraction data only were used to derive mean bond lengths involving hydrogen atoms. This version of CSD contained results for 49 854 single-crystals diffraction studies of organo- carbon compounds 10 324 of these satisfied the acceptance criteria listed below and were used in the averaging procedures.(i) Structure is ‘organic’, i.e. belongs to CSD classes 1-65 or 70.’ (ii) Atomic co-ordinates for the structure have been published and are available in CSD. (iii) Structure was determined from diffractometer data. (iv) Structure does not contain unresolved numeric data errors from the original publication (such errors are usually typographical and are normally resolved by consultation with the authors). (v) Structure was not reported to be disordered. (vi) Only structures of high precision were included on the basis of either (a) crystallographic R factor was d0.07 and the reported mean estimated standard deviation (e.s.d.) for the C-C bond lengths was dO.010 A (corresponds to AS flag = 1 or 2 in CSD), or (b) crystallographic R factor dO.05 and the mean e.s.d.for C-C bonds are not available in the database (AS = OinCSD). (vii) Where the structure of a given compound had been deter- mined more than once within the limits of (i)-(vi) then only the most precise determination was used. Program System.-All calculations were performed on the University of Cambridge IBM 3081D computer using the s2 programs BIBSER, CONNSER, RETRIEVE, GEOM78, and PLUT078.4 A stand-alone program was written to implement the selection criteria, whilst a new program (STATS) was used for statistical calculations described below. It was also necessary to modify CONNSER to improve the precision with which it locates chemical substructures.In particular the program was altered to permit the location of atoms with specified co- ordination numbers. This was essential in the case of carbon so that atoms with co-ordination numbers 2, 3, and 4 (equivalent to formal hybridization states sp', sp2, sp3) could be distin- guished easily and reliably. Considerable care was taken to ensure that the correct molecular fragment was located by GEOM78 in the generation of geometrical tabulations. This often involved the explicit specification of hydrogen atoms in fragments, and the extensive use of geometrical tests on valence and torsion angles. Considerable use was also made of chemical structural diagrams, which are available in the Cambridge in- house version of CSD for ca.65% of all entries. Chemical diagrams proved useful, for example, in identifying the various co-ordination environments commonly adopted by atoms such as As, B, P, etc. ClassiJication of Bonds.-The classification of bonds used in the Table is based on common functional groups, rings and ring systems, co-ordination spheres, etc. It is designed to: (i) appear logical, useful, and reasonably self-explanatory to chemists, crystallographers, and others who may use the Table; (ii) to permit a meaningful average value to be cited for each bond length. With reference to (ii), it was considered that a sample of bond lengths could be averaged meaningfully if (a) the sample was unimodally distributed; (b) the sample standard deviation (0)was reasonably small, ideally <ca.0.02 A; (c) there were no conspicuous outlying observations (those which occurred at >40 from the mean were automatically eliminated from the sample by STATS, other outliers were inspected carefully); (d) there were no compelling chemical reasons for further subdivision of the sample. Statistics.-Where there are less than four independent observations of a given bond length, then each individual observation is given explicitly in the Table. In all other cases the following statistics were generated by the program STATS. (i) The unweighted sample mean, d, where equation (1) holds and di is the ith observation of the bond length in a total sample of n observations.Recent work 8-10 has shown that the unweighted mean is an acceptable (even preferable) alternative to the weighted mean, where the ith observation is assigned a weight equal to l/02(di). This is especially true where structures have been pre-screened on the basis of precision. (ii) The sample median, rn. This has the property that half of the observations in the sample exceed rn, and half fall short of it. (iii) The sample standard deviation, denoted here as 0,where equation (2) holds. n CT = 1[(di -Cq2/(n -1)]+ (2)i= 1 (iv) The lower quartile for the sample, ql. This has the property that 25% of the observations are less than q1and 75% exceed it. (v) The upper quartile for the sample, 4,,.This has the property that 25% of the observations exceed 4,,, and 75% fall short of it. (vi) The number n of observations in the sample. J. CHEM. SOC. PERKIN TRANS. 11 1987 ril Figure 2. Effect of the removal of outliers (contributors which are >40 from the mean) for the C-C bond in Car-C-N fragments. Relevant statistics (see text) are: d m 0 Y1 4. n (a) before: 1.445 1.444 0.012 1.436 1.448 32 (b) after: 1.445 1.444 0.008 1.436 1.448 31 1-280 1-420 Figure 3. Skewed distribution of B-F bond lengths in BF,-ions: d = 1.365,m = 1.372, (J = 0.029, q1 = 1.352, qu = 1.390for 84 observ-ations. Note that d # m and that q1 qu are asymmetrically disposed about the mean d n 1-31 1.46 (a) n 1-34 1-41 1-41 1-46 (b) (C 1 Figure 4.Resolution of the bimodal distribution of C-N bond lengths in Car-N(Csp3), fragments: (a) complete distribution, (b) distribution for planar N, mean valence angle at N > 117.5", (c) distribution for pyramidal N, mean valence angle at N in the range 108-1 14" J. CHEM. SOC. PERKIN TRANS. II 1987 s3 (a) AsBBrCClFHIN 0 P S Se Si Te AS CspL C FOOOl N1'5 0 Figure5. (a) Distribution of mean bond length values reported in the Table by element pair. An * indicates a bonded pair represented by less than four contributors in the original data set. A t indicates bonded pairs located when restrictions on R factor and reported e.s.d. limits were lifted (see text). (b) Distribution of mean bond length values reported in the Table for C-C, C-0, and C-N The statistics given in the final Table correspond to distri- butions for which the automatic 40cut-off (see above) had been applied, and any manual removal of additional outliers (an infrequent operation) had been performed.In practice a very small percentage of observations were excluded by these methods. The major effect of removing outliers is to improve the sample standard deviation, as shown in Figure 2 in which a single observation is deleted. The statistics chosen for tabulation effectively describe the distribution of bond lengths in each case. For a symmetrical, normal distribution: the mean (d) will be approximately equal to the median (m);the lower and upper quartiles (ql,4") will be approximately symmetric about the median: m-q, 11 qu-m, and 95% of the observations may be expected to lie within +20 of the mean value.For a skewed distribution d and m may differ appreciably and q1 and qu will be asymmetric with respect to m.When a bond-length distribution is negatively skewed as in Figure 3, i.e. very short values are more common than very long values, then it may be due to thermal-motion effects; the distances used to prepare the Table were not corrected for thermal libration. In a number of cases the initial bond-length distribution was clearly bimodal, as in Figure 4a. All cases of biomodality were resolved on chemical grounds before inclusion in the Table, on the basis of hybridization, conformation-dependent conjugative interactions, etc.For example the histogram of Figure 4a was resolved into the two discrete unimodal distributions of Figures 4b,c which correspond to planar N(sp2) and pyramidal N(sp3), respectively. The mean valence angle at N was used as the discriminator, with a range of 108-114" for N(sp3) and 3117.5" for N(sp2). Content and Arrangement of the Table The upper triangular matrix of Figure 5a shows the 120 possible element pair combinations which can be formed from the 15 elements: As, B, Br, C, Cl, F, H, I, N, 0,P. S, Se, Si, Te. Figure 5a contains the number of discrete average bond lengths given in the Table for each element pair. A total of 682 average values are cited for 65 element pairs, of which 51 1 (75%) involve carbon.Bond length values from individual structures are given for a further 30 element pairs, indicated by * in Figure 5a. Individual structures are identified by their CSD reference code (eg. BOGSUL) and short-form literature references, ordered alpha- betically by reference code, are given in Appendix 2. A full bibliographic listing is available as Supplementary Publication No SUP 56701 (12 pp.).* For 8 element pairs the acceptance criterion (vi) was relaxed to include all available structures, irrespective of precision. These entries are denoted by p in the Table. No bonds were found for 25 element pairs within the subset of CSD used in this study. Each entry in the Table contains nine columns, of which six record the statistics of the bond length distribution described above.The content of the remaining three columns: Bond, Substructure, Note, are now described. Ordering of Entries: the 'Bond' Column.-For an element pair X-Y the primary ordering is alphabetic by element symbols according to the rows of Figure 5a, i.e. X changes slowest, Y fastest. The complete sequence runs from As-As to Te-Te with bonds involving carbon in their natural position: As-C .. . C-C ...C-Te. Within a given X-Y pair a secondary ordering is based on the co-ordination numbers (j)of X and Y, and on the nature of the bond between them. The bond definition is of the form Xu)-Y(j), with j decreasing fastest for Y, slowest for X, and with all single bonds preceding any multiple bonds.For carbon the formal hybridization state replaces (but is equivalent to) the co-ordination number and it is for this element that the ordering rules are most clearly required. The ordering of the most populous C-C, C-N, C-0 sections is illustrated in Figure 5b. The 13 possible C-C combinations * For details of Supplementary Publications see Instructions for Authors, J. Chem. SOC.,Perkin Trans. 2, 1987, Issue 1. s4 J. CHEM. SOC. PERKIN TRANS. 11 1987 CH20HI 8 9 1 1 3 [?"r 3 1 K 1 45c0): 5 CHOH 5 10 4 H OH anthracene azet id ine aziridine turan furanose 1 1 7 1 1 N' I 0'N2 4 Ir3 5(iN;li4 N3 4'8O'y: 4 f urazan f uroxan im idarole indole isoxazole 1 "13 6 pgN\p2 I II3 8, 5 NQp/N3 4 ox e tane oxirane naphthalene pheno t hiazine phosp h aze n e 1 160:4a.,0p 5rN"q25 4 3 I1 4 3 Oa 1 p iper id ine py ra n ose pyrazabole py raz ine pyrazole 1 1 1 "r07:5 4 NC 4": "m:: 4 TCNQ p y r idaz ine pyr irnidine 1H-pyrrole tetracyanoquinodimet hane tet rahyd rofuran 1 1 1 L 556cJ: 45rNT: 4":1 TII: te t rahydropyran tetrahydropyrrole tetrah yd rothiop h ene tetra h ydrot hiop y r an t et r a sele na f u Ivalene 1"c;: 451;si]23 3 tet rathia fulvalene thie tane t hiophene Figure 6.Alphabeticized index of ring systems referred to in the Table; the numbering scheme used in assembling the bond length data is given where necessary follow the sequence Csp3-Csp3, Csp3-Csp2, Csp3-Car, Csp3- DeJnition of 'Substructures'.-The chemical environment of Csp', Csp2-Csp2, Csp2-Car, Csp2-Csp', Car-Car, Car-Csp', each bond is normally defined by a linear formulation of the sub-Csp'-Csp', Csp2=Csp2, Car N Car, Csp'=Csp'.The symbol Car structure. The target bond is set in bold type, e.g. Car-CsN (aryl represents aryl carbon in six-membered rings, which is treated cyanides); C-CH2-0-Car (primary-alkyl aryl ethers); (C-O),-separately from Csp2 throughout the Table. The symbol 2: is P(N O), (phosphate diesters). Occasionally the chemical name used to indicate a delocalized double or aromatic bond of a functional group or ring system is used to define bond according to context. environment, e.g. in naphthalene, C2-C3; in imidazole, Nl-C2. J.CHEM. SOC. PERKIN TRANS. II 1987 s5 To avoid any possible ambiguity in these cases, we include conjugated systems; (c) any peculiarities of a particular bond numbered chemical diagrams in Figure 6. A combination of length distribution, e.g. sample dominated by C* = methyl; (d) chemical name and linear formulation is often employed to references to previously published surveys of crystallographic increase the precision of the definition, e.g. NH,-C=O in acylic results relevant to the substructure in question. We do not claim amides; C=C-C(=O)-C=O in benzoquinone. Finally, for very that these references are in any way comprehensive and we simple ions, the accepted conventional representation is deemed would be grateful to authors for notification (to F.H. A.) of any to be sufficient, e.g. in NO,- in SO4-, etc. omissions. This will serve to improve the content of any future The chemical definition of substructure may be followed by version of the Table. brief qualifying information, concerning substitution, conform- ational restrictions, etc. For example: Csp3-Csp3:in cyclobutane (any substituent); X-C-F, (X = C, H, N, 0);Car-NH-Csp3 (Nsp3:pyramidal). Where the generic symbol X is unqualified it Discussion denotes any element type, including hydrogen. If the qualifying It should be remembered that this Table has been derived from information is too extensive then it will be given as a Table the organic section of CSD. We are aware that a number of footnote (see below). organic bond types which occur very frequently in organo- The ‘Substructure’ column is designed to convey as much metallic compounds and metal complexes (e.g.C N C in cyclo- unambiguous information as possible within a small space. For pentadienyl, C-P in triphenylphosphine, etc.) are either absent Csp3we have employed the short forms C* and C#. C* indicates or poorly represented in this work. These omissions will be Csp3 whose bonds, additional to those specified in the linear rectified in Part 2 which is in preparation. We also note that formulation, are to C or H atoms only. C*-OH would then certain bond types listed here (e.g. As-0, Si-0, Si-N, etc.) will represent the group of alcohols CH,-OH, -C-CH,-OH, occur with greater frequency in inorganic compounds. The -C,-CH-OH, and -C,-C-OH.C* is frequently used to restrict interested reader is referred to the Inorganic Crystal Structure the secondary environment of a given bond to avoid the Database l1 for a machine-readable compendium of more perturbing influences of e.g. electronegative substituents. The relevant structural data. symbol C# is merely a space-saving device to indicate any Csp3 The tabulation given here represents the first stage in a major atom and includes C* as a subset. project designed to obtain the average geometries of functional groups, rigid rings and the low-energy conformations of flexible Use of the ‘Note’ Column.-The ‘Note’ column refers to the rings. Details of mean bond lengths, valence angles, and con- footnotes collected in Appendix 1.These record additional formational preferences in a wide range of substructures will information as follows: (a) additional details concerning the form the basis of a machine-readable ‘fragment library’ for use chemical definition of substructures, e.g. the omission of in molecular modeling and other areas of research. The syste- three- and four-membered rings; (b) statements of geometrical matic survey will be extended to derive information about constraints used in obtaining the cited average, e.g. definition distances, angles, directionality, and environmental dependence of planarity or pyramidality at N, torsional constraints in of hydrogen bonds and non-bonded interactions. Table. Bond Substructure d rn tT 41 4” n Note As(3)-As(3) X~-AS-AS-X~ 2.459 2.457 0.01 1 2.456 2.466 8 AS-B see CUDLOC (2.065), CUDLUI (2.041) As-Br see CODDEE, CODDII (2.346-3.203) AS(4)-C X~-AS-CH~ 1.903 1.907 0.016 1.893 1.916 12 (X), (C,0,S)As-Csp3 1.927 1.929 0.017 1.921 1.937 16 As-Car in Ph,As+ 1.905 1.909 0.012 1.897 1.912 108 (X),(C,O,S=)As-Car 1.922 1.927 0.016 1.908 1.934 36 As(3)-C x2-As-c~~~ 1.963 1.965 0.017 1.948 1.978 6 X2-As-Car 1.956 1.956 0.01 5 1.944 1.964 41 AS( 3)-C1 XZ-As-CI 2.268 2.256 0.039 2.247 2.28 1 10 As(6)-F in AsF,- 1.678 1.676 0.020 1.659 1.695 36 As(3)-I see OPIMAS (2.579, 2.590) As(3)-N(3) X ,-As-N-X~ 1.858 1.858 0.029 1.839 1.873 19 As(4)=N(2) see TPASSN (1.837) As(4)-0 (X) ,(=)As-OH 1.710 1.712 0.017 1.695 1.726 6 As(3t-O see ASAZOC, PHASOCO1 (1.787-1.845) As(4)=0 X3-Ad 1.661 1.66 1 0.01 6 1.652 1.667 9 As(3tP(3) see BELNIP (2.350, 2.362) t As(3t-P(3) see BUTHAZIO (2.124) t As( 3)-S X2-As-S 2.275 2.266 0.032 2.247 2.298 14 As(4)=S X3-AM 2.083 2.082 0.004 2.080 2.086 9 As(3)-Se(2) see COSDIX, ESEARS (2.355-2.401) t As( 3)-Si(4) see BICGEZ, MESIAD (2.351-2.365) t As(3)-Te(2) see ETEARS (2.571, 2.576) t B(n)-B(n) n = 5-7 in boron cages 1.775 1.773 0.03 1 1.763 1.786 688 B(4)-B(4) see CETTAW (2.041) B(4)-B(3) see COFVOI (1.698) B(3)-B(3) x2-B-B-x, 1.701 1.700 0.014 1.69 1 1.712 8 B(6)-Br 1.967 1.97 1 0.014 1.954 1.979 7 t B(4)-Br 2.017 2.008 0.03 1 1.990 2.044 15 t B(ntC n = 5-7: B-C in cages 1.716 1.717 0.020 1.707 1.728 96 n = 3-4: B-Csp3 not cages 1.597 1.599 0.022 1.585 1.61 1 29 n = 4: &Car 1.606 1.607 0.012 1.596 1.615 41 S6 J.CHEM. SOC. PERKIN TRANS. I1 1987 Table (continued) Bond Substructure d m (T 41 4" n Note n = 4: B-Car in Ph,B- 1.643 1.643 0.006 1.641 1.645 16 WnkC n = 3:B-Car 1.556 1.552 0.015 1.546 1.566 24 B(n)-CI B(4)-F B(5)-C1 and B(3)-CI B(4)-CI B-F (B neutral) 1.751 1.833 1.366 1.751 1.833 1.368 0.01 1 0.013 0.017 1.743 1.821 1.356 1.761 1.843 1.375 14 22 25 B--F in BF,- 1.365 1.372 0.029 1.352 1.390 84 B(4)-I B(4)-N(3) see TMPBTI (2.220, 2.253) in pyrazaboles X ,-B-N(=C)(X) 1.611 1.549 1.61 7 1.552 0.013 0.015 1.601 1.536 1.625 1.560 8 10 B(3)-N(3) X,-B-N-C,: all coplanar for z(BN) > 30" see BOGSUL, BUSHAY, 1.404 1.404 0.014 1.389 1.408 40 2 CILRUK (1.434-1.530) S 2-B-N-X 2 1.447 1.443 0.0 1 3 1.435 1.470 14 B(4)-0 B--0 in B04- for neutral B-0 see Note 3 1.468 1.468 0.022 1.453 1.479 24 3 B(3)-0(2)B(n)-P n=4B-P X2-B-0-X 1.367 1.922 1.367 1.927 0.024 0.027 1.349 1.900 1.382 1.954 35 10 n = 3: see BUPSIBlO (1.892, 1.893) B(4)-S W3kS B(4)-S(3) B(4)-S(2)N-BS2 1.930 1.896 1.806 1.927 1.896 1.806 0.009 0.004 0.010 1.925 1.893 1.799 1.934 1.899 1.816 10 6 28 Br-Br (=X-)(N-)BS see BEPZEB, TPASTB 1.851 2.542 1.854 2.548 0.013 0.01 5 1.842 2.526 1.859 2.55 1 10 4 Br-C Br-C* 1.966 1.967 0.029 1.951 1.983 100 4 Br-Csp3 (cyclopropane) 1.910 1.910 0.010 1.900 1.914 8 Br-Csp2 Br-Car (mono-Br + m,p-Br,) Br-Car (o-Br,) 1.883 1.899 1.875 1.881 1.899 1.872 0.01 5 0.012 0.01 1 1.874 1.892 1.864 1.894 1.906 1.884 31 119 8 4 4 4 -Br(2)-Cl Br-I Br-N Br-0 see TEACBR (2.362-2.402) see DTHIBRlO (2.646), TPHOSI (2.695) see NBBZAM (1.843) see CIYFOF 1.581 1.581 0.007 1.574 1.587 4 t Br-P see CISTED (2.366) Br-S(2) see BEMLIO (2.206) t Br-S( 3) Br-S(3)+ Br-Se Br-Si Br-Te see CIWYIQ (2.435, 2.453) see THINBR (2.321) see CIFZUM (2.508, 2.619) see BIZJAV (2.284) In Br,Te2- see CUGBAH (2.692-2.716) t t Br-Te(4) see BETUTElO (3.079, 3.015) csp3-csp3 Br-Te(3) see BTUPTE (2.835) C#-CH 2-CH 3 1.513 1.514 0.014 1.507 1.523 192 (C#),-CH-CH 3 1.524 1.526 0.015 1.518 1.534 226 (C#)3-C-CH2C#-CH ,-CH,-C# 1.534 1.524 1.534 1.524 0.01 1 0.014 1.527 1.516 1.541 1.532 825 2 459 (C#),-CH-CH,-C# 1.531 1.531 0.012 1.524 1.538 1217 (C#) 3-C-CH 2-C# 1.538 1.539 0.010 1.533 1.544 330 (C#),-CH-CH-(C#), (C#),-C-C-(C#),C*-C* (overall) in cyclopropane (any subst.) (c#) 3-c-c H-(C#) 2 1.542 1.556 1.588 1.530 1.510 1.542 1.556 1.580 1.530 1.509 0.01 1 0.01 1 0.025 0.015 0.026 1.536 1.549 1.566 1.521 1.497 1.549 1.562 1.610 1.539 1.523 321 215 21 5 777 888 56 7 in cyclobutane (any subst.) 1.554 1.553 0.02 1 1.540 1.567 679 8 in cyclopentane (C,H-subst.) 1.543 1.543 0.018 1.532 1.554 1641 in cyclohexane (C,H-subst.) cyclopropyl-C* (exocyclic) 1.535 1.518 1.535 1.518 0.016 0.019 1.525 1.505 1.545 1.531 2 814 366 7 cyclobutyl-C* (exocyclic) 1.529 1.529 0.016 1.519 1.539 376 8 cyclopentyl-C* (exocyclic) cyclohexyl-C* (exocyclic) 1.540 1.539 1.541 1.538 0.017 0.016 1.527 1.529 1.549 1.549 956 2 682 in cyclobutene (any subst.) in cyclopentene (C,H-subst.) in cyclohexene (C,H-subst.) 1.573 1.541 1.54 1 1.574 1.539 1.541 0.017 0.01 5 0.020 1.566 1.532 1.528 1.586 1.549 1.554 25 208 586 8 in oxirane (epoxide) in aziridine 1.466 1.480 1.466 1.48 1 0.01 5 0.02 1 1.458 1.465 1.474 1.496 249 67 9 9 in oxetane 1.541 1.541 0.019 1.527 1.557 16 in azetidine 1.548 1.543 0.018 1.536 1.558 22 oxiranyl-C* (exocyclic) 1.509 1.507 0.018 1.497 1.519 333 9 csp3-csp2 aziridinyl-C* (exocyclic) CH ,-C=C 1.512 1.503 1.512 1.504 0.018 0.01 1 1.496 1.497 1.526 1.509 13 215 9 C#-CH,-C=C 1.502 1.502 0.013 1.494 1.510 483 (C#),-CH-Ce 1.510 1.510 0.014 1.501 1.518 564 (C#),-c-c=c 1.522 1.522 0.016 1.51 1 1.533 193 J.CHEM. SOC. PERKIN TRANS. JI 1987 s7 Table (conrinued) Bond Substructure d m 0 41 4" n Note Csp J-CspL C*-C=C (overall) 1.507 1.507 0.01 5 1.499 1.517 1456 5 C*-C=C (endocyclic) in cyclopropene 1.509 1.508 0.016 1.500 1.516 20 10 in cyclobutene in cyclopentene 1.513 1.512 1.512 1.512 0.01 8 0.014 1.500 1.502 1.525 1.521 50 208 8 in cyclohexene 1.506 1SO5 0.016 1.495 1.516 39 1 in cyclopentadiene 1.502 1.503 0.019 1.490 1.51 5 18 in cyclohexa-1,3-diene 1SO4 1.504 0.017 1.49 1 1.517 56 C*-C=C (exocyclic): c yclopropen yl-C* 1.478 1.475 0.012 1.470 1.485 7 10 cyclobutenyl-C* 1.489 1.483 0.015 1.479 1.496 11 8 cyclopentenyl-C* 1.504 1.506 0.012 1.495 1.512 115 cyclohexen yl-C* C*-CH=O in aldehydes 1.51 1 1.510 1.511 1.510 0.013 0.008 1.502 1.501 1.519 1.518 292 7 (C *)2-c=o in ketones 1.511 1.51 1 0.01 5 1.501 1.521 952 11 in cyclobutanone 1.529 1.530 0.016 1.514 1.545 18 in cyclopentanone 1.514 1.514 0.016 1.505 1.523 312 acyclic and 6+ rings C*-COOH in carboxylic acids 1.509 1.502 1SO9 1 SO2 0.016 0.014 1.499 1.495 1.519 1.510 626 176 C*-COO- in carboxylate anions 1.520 1.521 0.01 1 1.516 1.528 57 c*-c(=o)(-oc*) in acyclic esters in p-lactones 1.497 1.519 1.496 1.519 0.018 0.020 1.484 1.500 1.509 1.538 553 4 12 13 in y-lactones 1.512 1.512 0.015 1.501 1.521 110 12 in &-lactones 1.504 1 SO2 0.01 3 1.495 1.517 27 12 cyclopropyl (C)-C=O in ketones, acids and esters 1.486 1.485 0.018 1.474 1.497 105 7 C*-C(=O)(-NH,) in acyclic amides 1.514 1.512 0.016 1.506 1.526 32 14 C*-C(=O)(-NHC*) in acyclic amides 1.506 1.505 0.01 2 1.498 1.515 78 14 C*-C(=O)[-N(C*),] in acyclic amides 1.505 1.505 0.01 1 1.496 1.517 15 14 Csp3-Car CH3-Car 1SO6 1.507 0.01 1 1.501 1.513 454 C#-CH,-Car 1.510 1.510 0.009 1 SO5 1.516 674 (C#)2-CH-Car 1.515 1.515 0.01 1 1.508 1.522 363 (C#),-C-Car 1.527 1.530 0.016 1.517 1.539 308 C*-Car (overall) 1.513 1.513 0.014 1SO5 1.521 1813 csp3-csp' cyclopropyl (C)-Car C*-C& C#-C& 1.490 1.466 1.472 1.490 1.465 1.472 0.015 0.010 0.012 1.479 1.460 1.464 1.503 1.469 1.481 90 21 88 7 15 15 C*-C=N 1.470 1.469 0.013 1.463 1.479 106 7b cyclopropyl (C)-C=N 1.444 1.447 0.010 1.436 1.451 38 7 csp2-csp2 c=c-c=c (conjugated) (unconjugated) (over all) c=c-c=c-c=c 1.45 5 1.478 1.460 1.443 1.455 1.476 1.460 1.445 0.01 1 0.012 0.015 0.01 3 1.447 1.470 1.450 1.431 1.463 1.479 1.470 1.454 30 8 38 29 16,18 17,18 18 C=C-C=C (endocyclic in TCNQ) 1.432 1.433 0.012 1.424 1.44 1 280 19 c=C-C(=O)(-C*) (conjugated) (unconjugated) (overall) 1.464 1.484 1.465 1.462 1.486 1.462 0.018 0.017 0.018 1.453 1.475 1.453 1.476 1.497 1.478 21 1 14 226 16,18 17,18 c=c-C(=o)-c=c in benzoquinone (C,H-subst.only) in benzoquinone (any subst.) non-quinonoid CS-COOH 1.478 1.478 1.456 1.475 1.476 1.478 1.455 1.476 0.01 1 0.03 1 0.012 0.015 1.469 1.464 1.447 1.46 1 1.488 1.498 1.464 1.488 28 172 28 22 c=c-cooc* 1.488 1.489 0.014 1.478 1.497 113 c=c-coo- 1.502 1.499 0.017 1.488 1.510 11 HOOC-COOH 1.538 1.537 0.007 1.535 1.541 9 HOOC-COO --0oc-coo- 1.549 1.564 1.552 1.559 0.009 0.022 1.546 1.554 1.553 1.568 13 9 formal Csp2-Csp2 single bond in selected Csp2-Car non-fused heterocycles: in lH-pyrrole (C3-C4) in furan (C3-C4) in thiophene (C3-C4) in pyrazole (C3-C4) in isoxazole (C3-C4) in furazan (C3-C4) in furoxan (C3-C4) C=C-Car 1.412 1.423 1.424 1.410 1.425 1.428 1.417 1.410 1.423 1.425 1.412 1.425 1.427 1.417 0.016 0.016 0.015 0.016 0.016 0.007 0.006 1.401 1.412 1.415 1.400 1.413 1.422 1.412 1.427 1.43 3 1.433 1.418 1.438 1.435 1.422 29 62 40 20 9 6 14 (conjugated) 1.470 1.470 0.015 1.463 1.480 37 16,18 S8 J.CHEM. SOC. PERKIN TRANS. II 1987 Table (continued) Bond Substructure d m 41 4" n Note Csp2-Car 1.488 1.490 0.012 1.480 1.496 87 17,18 (overall)cyclopropenyl (C=C)-Car 1.483 1.447 1.483 1.448 0.015 0.006 1.472 1.441 1.494 1.452 8 124 10 Car-C(=O)-C* 1.488 1.489 0.016 1.478 1.500 84 Car-C(=O)-Car 1.480 1.481 0.017 1.468 1.494 58 Car-COOH 1.484 1.485 0.014 1.474 1.49 1 75 Car-C(=O)(-OC*) Car-COO - 1.487 1.504 1.487 1.509 0.012 0.014 1.480 1.495 1.494 1.512 218 26 Car-C(=O)-NHZ 1.500 1.503 0.020 1.498 1.510 19 Car-C=N-C# (conjugated) (unconjugated) 1.476 1.491 1.478 1.490 0.014 0.008 1.466 1.485 1.486 1.496 27 48 16 17 (overall) 1.485 1.487 0.01 3 1.481 1.493 75 in indole (C3-C3a) 1.434 1.434 0.01 1 1.428 1.439 40 cspz-csp 1 c=C-c=c 1.43 1 1.427 0.014 1.425 1.441 11 7b C=C-C=N in TCNQ 1.427 1.427 0.010 1.420 1.433 280 19 Car-Car Car-Csp ' in biphenyls (ortho subst.all H) (2 1 non-H ortho-subst.) Car-C=C Car-GN 1.487 1.490 1.434 1.443 1.488 1.49 1 1.436 1.444 0.007 0.010 0.006 0.008 1.484 1.486 1.430 1.436 1.493 1.495 1.437 1.448 30 212 37 31 Csp'-Csp' CSP~=CSP~ CS-C=c C*-CH=CHz 1.377 1.299 1.378 1.300 0.012 0.027 1.374 1.280 1.384 1.31 1 21 42 (C*)Z-C<H 2 C*-CH=C H-C * 1.321 1.321 0.01 3 1.313 1.328 77 (cis) 1.317 1.318 0.01 3 1.310 1.323 106 (trans) 1.312 1.31 1 0.01 1 1.304 1.320 19 (overall) (C*)Z-C=CH-C * (C* )z-C=C--K * 12 (C*,H)z-C=C-( C*,H)z (overall) in cyclopropene (any subst.) 1.316 1.326 1.331 1.322 1.294 1.317 1.328 1.330 1.323 1.288 0.015 0.01 1 0.009 0.014 0.017 1.309 1.319 1.326 1.315 1.284 1.323 1.334 1.334 1.33 1 1.302 127 168 89 493 10 5 10 in cyclobutene (any subst.) in cyclopentene (C,H-subst.) 1.335 1.323 1.335 1.324 0.019 0.013 1.324 1.314 1.347 1.331 25 104 8 in cyclohexene (C,H-subst.) 1.326 1.325 0.012 1.318 1.334 196 C=C=C (allenes, any subst.) 1.307 1.307 0.005 1.303 1.310 18 C=C-C=C (C,H subst., conjugated) 1.330 1.330 0.014 1.322 1.338 76 16 C=C-C=C-C=C (C,H subst., conjugated) 1.345 1.345 0.012 1.337 1.350 58 16 C=C-Car (C,H subst., conjugated) 1.339 1.340 0.01 1 1.334 1.346 124 16 C=C in cyclopenta-1,3-diene (any subst.) 1.341 1.341 0.017 1.328 1.356 18 C=C in cyclohexa-1,3-diene (any subst.) in C=C-C=O 1.332 1.332 0.013 1.323 1.34 1 56 (C,H subst., conjugated) (C,H subst., unconjugated) (C,H subst., overall) in cyclohexa-2,5-dien-l -ones 1.340 1.331 1.340 1.329 1.340 1.330 1.339 1.327 0.013 0.008 0.013 0.01 1 1.332 1.326 1.332 1.321 1.348 1.339 1.348 1.335 211 14 226 28 16,18 17,18 in p-benzoquinones (C*,H subst.) 1.333 1.337 0.011 1.325 1.338 14 (any subst.) in TCNQ 1.349 1.339 0.030 1.330 1.364 86 (endocyclic) (exocyclic) 1.352 1.392 1.353 1.391 0.010 0.017 1.345 1.379 1.358 1.405 142 139 19 19 C=C-OH in enol tautomers 1.362 1.360 0.020 1.349 1.370 54 in heterocycles (any subst.): lH-pyrrole (C2-C3, C4-C5) furan (C2-C3, CW5) 1.375 1.341 1.377 1.342 0.018 0.02 1 1.361 1.329 1.388 1.351 58 125 thiophene (C2-C3, C4-C5) 1.362 1.359 0.025 1.346 1.377 60 Car 'vCar pyrazole (C4-C5) imidazole (C4-C5) isoxazole (C4-C5) indole (C2-C3) in phenyl rings with C*,H subst.only H-C -N C-H 1.369 1.360 1.341 1.364 1.380 1.372 1.361 1.336 1.363 1.38 1 0.019 0.014 0.012 0.012 0.013 1.362 1.352 1.331 1.355 1.372 1.383 1.367 1.355 1.371 1.388 20 44 9 40 2 191 C*-C N C-H c*-c -N c-c* 1.387 1.397 1.388 1.397 0.010 0.009 1.382 1.392 1.393 1.403 89 1 182 C 21 C (overall) 1.384 1.384 0.013 1.375 1.391 3 264 F-C -N C-Fc1-c 1: c-c1 1.372 1.388 1.374 1.389 0.011 0.014 1.366 1.380 1.380 1.398 84 152 4 4 in naphthalene (D,,,, any subst.) c142 1.364 1.364 0.014 1.356 1.373 440 C2-C3 1.406 1.406 0.014 1.397 1.415 218 Cl-C8a C4a-C8a 1.420 1.422 1.419 1.424 0.012 0.01 1 1.412 1.417 1.426 1.429 440 109 J.CHEM. SOC. PERKIN TRANS. 11 1987 s9 Table (continued) Bond Substructure d m 0 41 4" n Note Cur N Cur in anthracene (DZh,any subst.) Cl-C2 1.356 1.356 0.009 1.350 1.360 56 C2-C3 1.410 1.410 0.010 1.40 1 1.416 34 C 1-C9a 1.430 1.430 0.006 1.426 1.434 56 C4a-C9a 1.435 1.436 0.007 1.429 1.440 34 C9-C9a 1.400 1.402 0.009 1.395 1.406 68 in pyridine (C,H subst.) 1.379 1.381 0.012 1.371 1.387 276 20 (any subst.) 1.380 1.380 0.015 1.371 1.389 537 20 in pyridinium cation (N+-H; C,H subst.on C) C2-C3 1.373 1.375 0.012 1.368 1.380 30 c3-c4 1.379 1.380 0.01 1 1.371 1.388 30 (N+-X; C,H subst. on C) C2-C3 1.373 1.372 0.019 1.362 1.382 151 c3-c4 1.383 1.385 0.019 1.372 1.394 151 in pyrazine (H subst. on C) 1.379 1.377 0.010 1.370 1.388 10 (any subst. on C) 1.405 1.405 0.024 1.388 1.420 60 in pyrimidine (C,H subst. on C) 1.387 1.389 0.018 1.379 1.400 28 csp'Ksp 1 x-CS-x 1.183 1.183 0.014 1.174 1.193 119 15 C, H-CK-C, H 1.181 1.181 0.014 1.173 1.192 104 15 in C=C-C(sp2,ar) 1.189 1.193 0.010 1.181 1.195 38 15 in C=C-C=C 1.192 1.192 0.010 1.187 1.197 42 15 in CHS-C# 1.174 1.174 0.01 1 1.167 1.180 42 15 Csp3-Cl Omitting 1,2-dichlorides: C-CH2-CI 1.790 1.790 0.007 1.783 1.795 13 4 C,-CH-CI 1.803 1.802 0.003 1.800 1.807 8 4 c,-c-CI 1.849 1.856 0.01 1 1.837 1.858 5 4 X-CHZ-CI (X = C,H,N,O) 1.790 1.79 1 0.01 1 1.783 1.797 37 4 X2-CH-CI (X = C,H,N,O) 1.805 1.803 0.014 1.800 1.812 26 4 X3-C-CI (X = C,H,N,O) 1.843 1.838 0.014 1.835 1.858 7 4 X,-C-CI, (X = C,H,N,O) 1.779 1.776 0.01 5 1.769 1.790 18 4 X-C-CI, (X = C,H,N,O) 1.768 1.765 0.011 1.76 1 1.776 33 4 Cl-CH(-C)-CH(-C)-Cl 1.793 1.793 0.013 1.786 1.800 66 4 cl-C(-C,)-C(-C,)-Cl 1.762 1.760 0.010 1.757 1.765 54 4 cyclopropyl-C1 1.755 1.756 0.01 1 1.749 1.763 64 csp2-c1 CX-CI (C,H,N,O subst.on C) 1.734 1.729 0.019 1.719 1.748 63 4 C=C-CI, (C,H,N,O subst. on C) 1.720 1.716 0.013 1.708 1.729 20 4 CI-c=c-CI 1.713 1.71 1 0.01 1 1.705 1.720 80 4 Car-C1 Car-CI (mono-C1 + m,p-Cl,) 1.739 1.741 0.010 1.734 1.745 340 4 Car-CI (o-Cl,) 1.720 1.720 0.010 1.713 1.717 364 4 Csp'-CI see HCLENElO (1.634, 1.646) Csp3-F Omitting 1,2-difluorides C-CH,-F and C,-CH-F 1.399 1.399 0.017 1.389 1.408 25 4 C3-C-F 1.428 1.431 0.009 1.42 1 1.435 11 4 (C*,H),-C-F, 1.349 1.347 0.012 1.342 1.356 58 4 C*-C-F3 1.336 1.334 0.007 1.330 1.344 12 4 F-C*-C*-F 1.371 1.374 0.007 1.362 1.375 26 4 X3-C-F (X = C,H,N,O) 1.386 1.389 0.033 1.373 1.408 70 4 XZ-C-F, (X = C,H,N,O) 1.351 1.349 0.01 3 1.342 1.356 58 4 X-C-F, (X = C,H,N,O) 1.322 1.323 0.015 1.3 14 1.332 309 4 F-C(-X),-C(-X),-F (X = C,H,N,O) 1.373 1.374 0.009 1.362 1.377 30 4 F-C(-X),-NO, (X = any subst.) 1.320 1.319 0.009 1.312 1.327 18 Csp2-F C=C-F (C,H,N,O subst.on C) 1.340 1.340 0.013 1.334 1.346 34 4 Cur-F Car-F (mono-F + m,p-F,) 1.363 1.362 0.008 1.357 1.368 38 4 Car-F (o-F,) 1.340 1.340 0.009 1.336 1.344 167 4 Csp3-H C-C-H, (methyl) 1.059 1.06 1 0.030 1.039 1.083 83 21 C,-C-H, (primary) 1.092 1.095 0.013 1.088 1.099 100 21 C3-C-H (secondary) 1.099 1.097 0,004 1.095 1.103 14 21 C,,,-C-H (primary and secondary) 1.09 3 1.095 0.012 1.089 1.100 118 21 X-C-H, (methyl) 1.066 1.074 0.028 1.049 1.087 160 21 X,-C-H, (primary) 1.092 1.095 0.012 1.088 1.099 230 21 X,-C-H (secondary) 1.099 1.099 0.007 1.095 1.103 117 21 X,,,-C-H (primary and secondary) 1.094 1.096 0.011 1.09 1 1.100 348 21 Csp2-H CCX-H 1.077 1.079 0.012 1.074 1.085 14 21 Cur-H Car-H 1.083 1.083 0.01 1 1.080 1.087 218 21 csp3-I C*-I 2.162 2.159 0.015 2.149 2.179 15 4 Car-I Car-I 2.095 2.095 0.015 2.089 2.104 51 4 CSP ,-N(4) C*-NH3+ 1.488 1.488 0.013 1.482 1.495 298 (C*),-NH2+ 1.494 1.493 0.016 1.484 1.503 249 (C*) 3-NH 1.502 1.502 0.015 1.49 1 1.512 509+ (C*)4-N 1.510 1.509 0.020 1.496 1.523 319+ +C*-N (overall) 1.499 1.498 0.01 8 1.488 1.510 1 370 s10 J.CHEM. SOC. PERKIN TRANS. II 1987 Table (continued) Bond Substructure d m 0 41 4" n Note csp3-N(3) C*-Nf in N-subst. pyridinium 1.485 1.484 0.009 1.477 1.490 32 C*-NH2 (Nsp3: pyramidal) 1.469 1.470 0.010 1.462 1.474 19 22 (C*)2-NH (Nsp3:pyramidal) 1.469 1.467 0.012 1.461 1.477 152 5,22 (C*),-N (Nsp3:pyramidal) 1.469 1.468 0.014 1.460 1.476 1042 5,22C*-Nsp3 (overall) 1.469 1.468 0.014 1.460 1.476 1201 CSP 3-N~p3 in aziridine 1.472 1.471 0.016 1.464 1.482 134 in azetidine 1.484 1.48 1 0.018 1.472 1.495 21 in tetrahydropyrrole 1.475 1.473 0.016 1.464 1.483 66 in piperidine 1.473 1.473 0.01 3 1.460 1.479 240 Csp3-Nsp2 (N planar) in: 23 acyclic amides C*-NH-C=O 1.454 1.45 1 0.01 1 1.446 1.461 78 14 p-lactams C*-N(-X)-C=O (endo) 1.464 1.465 0.012 1.458 1.475 23 13 y-lactams C*-NH-C=O (endo) 1.457 1.458 0.011 1.449 1.465 20 13 C *-N(-C *)-C=O (endo) 1.462 1.46 1 0.010 1.453 1.466 15 13 C *-N(-C*)-C=O (exo) 1.458 1.456 0.014 1.448 1.465 15 13 &lactams C*-NH-C=O (endo) 1.478 1.472 0.016 1.467 1.49 1 6 14 C*-N(-C*)-C=O (endo) 1.479 1.476 0.007 1.475 1.482 15 14 C*-N(-C*)-C--O (exo) 1.468 1.471 0.009 1.462 1.477 15 14 nitro compounds (1,Zdinitro omitted): C-CH2-NO2 1.485 1.483 0.020 1.478 1.502 8 CZ-CH-NO, 1.509 1 SO9 0.01 1 1.502 1.51 1 12 C3-C-NO2 1.533 1.533 0.013 1.530 1.539 17 c2-C-(NO,) 2 1.537 1.536 0.016 1.525 1.550 19 172-dinitro:N02-C*-C*-N02 1.552 1.550 0.023 1.536 1.572 32 Csp3-N(2) C#-N=N 1.493 1.493 0.020 1.477 1.506 54 C *-NX-C ar 1.465 1.468 0.01 1 1.46 1 1.472 75 CLyp2-N(3) C=C-NH, Nsp2 planar 1.336 1.344 0.017 1.317 1.348 10 23 C=C-NH-C# Nsp2 planar 1.339 1.340 0.016 1.327 1.35 1 17 23 CS-N-( C#) 2 Nsp2 planar 1.355 1.358 0.014 1.341 1.363 22 23 Nsp3 pyramidal 1.416 1.418 0.01 8 1.397 1.432 18 22 Csp2-Nsp2 (N planar) in: 23 acyclic amides NH,-C=O 1.325 1.323 0.009 1.318 1.33 1 32 14 C *-NH-C=O 1.334 1.333 0.01 1 1.326 1.343 78 14 (C*)2-N-C=O 1.346 1.342 0.01 1 1.339 1.356 5 14 P-lactams C*-NH-C=O 1,385 1.388 0.019 1.374 1.396 23 13 y-lactams C *-NH-C=O 1.33 1 1.331 0.01 1 1.326 1.337 20 13 C *-N(-C*)-C=O 1.347 1.344 0.014 1.335 1.359 15 13 &-lactams C*-NH-C=O 1.334 1.334 0.006 1.330 1.339 6 14 C*-N(-C*)-C=O 1.352 1.353 0.010 1.344 1.356 15 14 peptides C#-N(-X)-C(-C#)(=O) 1.333 1.334 0.01 3 1.326 1.340 380 24 ureas (NH2) ,-C=O 1.334 1.334 0.008 1.329 1.339 48 25,26 (C#-NH)Z-C=O 1.347 1.345 0.010 1.341 1.354 26 25 C(C#),-Nl 2-c=0 1.363 1.359 0.014 1.354 1.370 40 25,27 thioureas 1.346 1.343 0.023 1.328 1.361 192 (X2N) ,-C=S imides [C#-C(=O)] 2-NH 1.376 1.377 0.012 1.369 1.383 64 [C#-C(=O)] 2-N-C# 1.389 1.383 0.017 1.376 1.404 38 2-C(a)][CS~ 2-N-C # 1.396 1.396 0.0 10 1.389 1.403 46 [Csp2-C(=O)] 2-N-Csp2 1.409 1.406 0.020 1.391 1.419 28 guanidinium [C-(NH,),]+ (unsubst.) 1.321 1.320 0.008 1.314 1.327 39 (any subst.) 1.328 1.325 0.01 5 1.317 1.333 140 in heterocyclic systems (any subst.) 1H-pyrrole (Nl-C2, N1-C5) 1.372 1.374 0.01 6 1.363 1.384 58 indole (Nl-C2) 1.370 1.370 0.012 1.364 1.377 40 pyrazole (Nl-C5) 1.357 1.359 0.012 1.347 1.365 20 imidazole (Nl-C2) 1.349 1.349 0.018 1.338 1.358 44 imidazole (Nl-C5) 1.370 1.370 0.010 1.365 1.377 44 Csp2-N(2) in imidazole (N3-C4) 1.376 1.377 0.01 1 1.369 1.384 44 +Car-N(4) Car-N -(C,H)3 1.465 1.466 0.007 1.461 1.470 23 Car-N( 3) Car-NH, (Nsp': planar) 1.355 1.360 0.020 1.340 1.372 33 23 (Nsp3: pyramidal) 1.394 1.396 0.011 1.385 1.403 25 22 (overall) 1.375 1.377 0.025 1.363 1.394 98 28 J.CHEM. SOC. PERKIN TRANS. II 1987 s11 Table (continued) Bond Substructure d m Q 41 4" n Note Car-N( 3) Car-NH-C# (Nsp2:planar) 1.353 1.353 0.007 1.347 1.359 16 23 (Nsp3: pyramidal) 1.419 1.423 0.017 1.412 1.432 8 22 (overall) Car-N-( C#) 2 1.380 1.364 0.032 1.353 1.412 31 28 (Nsp2:planar) 1.371 1.370 0.016 1.363 1.382 41 23 (Nsp3: pyramidal) 1.426 1.425 0.01 1 1.42 1 1.43 1 22 22 (overall) in indole (Nl-C7a) 1.390 1.372 1.385 1.372 0.030 0.007 1.366 1.367 1.420 1.376 69 40 28 Car-N( 2) Csp2=N(3) Csp2=N(2) Car-NO, Car-N=N in furoxan (+N2=C3) Car-C=N-C# 1.468 1.431 1.316 1.279 1.469 1.435 1.316 1.279 0.014 0.020 0.009 0.008 1.460 1.422 1.311 1.275 1.476 1.442 1.324 1.285 556 26 14 75 (C,H),-C=N-OH in oximes 1.28 1 1.280 0.013 1.273 1.288 67 S-C=N-X 1.302 1.302 0.02 1 1.285 1.319 36 in pyrazole (N243) in imidazole (C2=N3) 1.329 1.313 1.331 1.314 0.014 0.01 1 1.315 1.307 1.339 1.319 20 44 in isoxazole (N243) 1.314 1.315 0.009 1.305 1.320 9 Car 'v N(3) in furazan (N243, CkN5) in furoxan (CkN5) C 2: N+-H (pyrimidinium) C N N+-C* (pyrimidinium) 1.298 1.304 1.335 1.346 1.299 1.306 1.334 1.346 0.006 0.008 0.015 0.010 1.294 1.300 1.325 1.340 1.303 1.308 1.342 1.352 12 14 30 64 Car 'v N(2) C 2: N+-O-(pyrimidinium) C 2: N (pyridine) 1.362 1.337 1.359 1.338 0.013 0.012 1.353 1.330 1.369 1.344 56 269 C 1: N (pyrazine) 1.336 1.335 0.022 1.319 1.347 120 C N N 2: C (pyrimidine) N 2: C 2: N (pyrimidine) 1.339 1.333 1.338 1.335 0.015 0.01 3 1.333 1.326 1.342 1.337 28 28 C N N (pyrimidine) (overall) 1.336 1.337 0.014 1.331 1.339 56 in any 6-membered N-containing aromatic ring: H-C N N 2: C-H H-C 2: N N C-C* 1.334 1.339 1.334 1.341 0.014 0.013 1.327 1.336 1.341 1.345 146 38 C*-C -N N C-C* 1.345 1.345 0.008 1.342 1.348 24 Csp'rN(2) Csp'=N( 1) C 2: N 2 C (overall) X-S-Ce (isocyanide) C*-C=N 1.336 1.144 1.136 1.337 1.147 1.137 0.014 0.006 0.010 1.329 1.140 1.131 1.344 1.148 1.142 204 6 140 C=C-CzN in TCNQ 1.144 1.144 0.008 1.139 1.149 284 19 X-N+=N Car-GN 1.138 1.144 1.138 1.141 0.007 0.012 1.133 1.138 1.143 1.151 31 10 (S-C=N)- 1.155 1.156 0.0 12 1.147 1.165 14 csp3-0(2) in alcohols CH,-OH 1.413 1.414 0.018 1.395 1.425 17 C-CH ,-OH 1.426 1.426 0.01 1 1.420 1.431 75 C 2-C H-0 H 1.432 1.431 0.01 1 1.425 1.439 266 C,-C-OH C*-OH (overall) in dialkyl ethers CH 3-0-C* 1.440 1.432 1.416 1.440 1.43 1 1.418 0.012 0.01 3 0.016 1.432 1.424 1.405 1.449 1.441 1.426 106 464 110 29 C-CH Z-O-C* C 2-C H-O-C * 1.426 1.429 1.424 1.430 0.01 1 0.010 1.418 1.420 1.435 1.437 34 53 c,-c-0-c* C*-0-C* (overall) in aryl alkyl ethers CH,-&Car 1.452 1.426 1.424 1.450 1.425 1.424 0.01 1 0.019 0.012 1.445 1.414 1.417 1.458 1.437 1.43 1 39 236 616 5 29 C-CHZ-O-Car 1.431 1.430 0.013 1.422 1.438 188 C,-CH-O-Car 1.447 1.446 0.020 1.435 1.466 58 C3-C-O-Car 1.470 1.469 0.018 1.456 1.483 55 C*-0-Car (overall) in alkyl esters of carboxylic acids CH,-O-C(=O)-C* C-CH 2-O-C(=O)-C* C2-CH-O-C(=O)-C* C3-C-0-C(q-C* C*-O-C(=O)-C* (overall) 1.429 1.448 1.452 1.460 1.477 1.450 1.427 1.449 1.453 1.460 1.475 1.451 0.01 8 0.010 0.009 0.010 0.008 0.014 1.419 1.442 1.445 1.454 1.472 1.442 1.436 1.455 1.458 1.465 1.484 1.459 917 200 32 78 6 3 14 12,29 C*-O-C(=O>-C==C (overall) C*-O-C(=O)-C(phenyl) (overall) in alkyl esters of a$-unsaturated acids: in alkyl esters of benzoic acid 1.453 1.454 1.452 1.454 0.01 3 0.012 1.444 1.446 1.459 1.463 112 219 oxirane (epoxides) (any subst.) oxetane (any subst.) tetrahydrofuran (C,H subst.) in ring systems 1.446 1.463 1.442 1.446 1.460 1.441 0.0 14 0.015 0.017 1.438 1.451 1.430 1.456 1.474 1.451 498 16 154 9 J.CHEM. SOC. PERKIN TRANS. 11 1987 Table (continued) Bond Substructure d m 0 41 4" n Note csp3-0(2) tetrahydropyran (C,H subst.) 1.44 1 1.442 0.01 5 1.431 1.451 22 p-lactones: C*-0-C(=O) 1.492 1.494 0.010 1.481 1.501 4 16 y-lactones: C*-0-C(=O) 1.464 1.464 0.0 12 1.455 1.473 110 12 6-lactones: C*-O-C(=O) 1.46 1 1.464 0.017 1.452 1.473 27 12 0-C-0 system in gem-diols, and pyranose and furanose sugars: 30,3 1 HO-C *-0H 1.397 1.401 0.012 1.388 1.405 18 C5-05-C ,-0 H in pyranoses 0, axial (a): 1.439 1.440 0.008 1.432 1.445 29c5-05 1.427 1.426 0.012 1.42 1 1.432 29041 1.403 1.400 0.012 1.391 1.412 29c1-01 0, equatorial (p): 1.43 5 1.436 0.008 1.429 1.440 17c5-05 1.430 1.431 0.010 1.424 1.436 1705-c 1 1.393 1.393 0.007 1.386 1.399 17c1-01 a + p (overall): 1.439 1.440 0.008 1.432 1.446 60c5-05 05-c1 1.430 1.429 0.012 1.421 1.436 60 c1-01 1.40 1 1.399 0.01 1 1.392 1.407 60 C4-0,-C,-0,H in furanoses (overall values) 1.442 1.446 0.012 1.436 1.449 18c4-04 04-c 1 1.432 1.432 0.012 1.421 1.443 18 1.404 1.405 0.01 3 1.397 1.409 18Ci-01 C5-0,-C,-0,-C* in pyranoses 0, axial (a): 1.439 1.438 0.010 1.433 1.446 67c5-05 04, 1.417 1.417 0.009 1.410 1.424 67 C1-0, 1.409 1.409 0.014 1.401 1.417 67 0,-c* 1.435 1.435 0.013 1.427 1.443 67 0, equatorial (p): 1.434 1.435 0.006 1.429 1.439 39c5-05 1.424 1.424 0.008 1.418 1.431 3905-c1 c1-0 1 1.390 1.390 0.01 1 1.381 1.400 390,-c* 1.437 1.438 0.013 1.428 1.445 39 0: + p (overall): 1.436 1.436 0.009 1.431 1.442 126c5-05 1.419 1.419 0.01 1 1.412 1.426 12605-c1 1.402 1.403 0.016 1.391 1.413 126C1-01 01-c* 1.436 1.436 0.013 1.428 1.445 126 C4-04-Cl-0,-C* in furanoses (overall values) 1.443 1.445 0.01 3 1.429 1.453 23c4-04 1.421 1.418 0.012 1.413 1.43 1 2304-c 1 c1-01 1.410 1.409 0.014 1.401 1.420 23 0,-c* 1.439 1.437 0.014 1.429 1.449 23 Miscellaneous: C#-O-Six, 1.416 1.416 0.017 1.405 1.428 29 c*-&SO y-c 1.465 1.46 1 0.014 1.454 1.475 33 Csp2-0(2) in enols: =-OH 1.333 1.331 0.01 7 1.324 1.342 53 in enol esters: W-O-C* 1.354 1.353 0.016 1.341 1.363 40 in acids: C*-C(=O)-OH 1.308 1.311 0.0 19 1.298 1.320 174 C=C-C(=O)-OH 1.293 1.295 0.019 1.279 1.307 22 Car- C(=O)-OH 1.305 1.311 0.020 1.291 1.317 75 in esters: c*-C(=O)-0-c * 1.336 1.337 0.014 1.328 1.346 55 1 12,29 c=c-C(=o)-0-c* 1.332 1.331 0.011 1.324 1.339 112 Car-C(=O)-0-C* 1.337 1.335 0.013 1.329 1.344 219 12 c*-C(=O)-O-C=C 1.362 1.359 0.018 1.351 1.374 26 C*-C(=O)-0-C=c 1.407 1.405 0.017 1.394 1.420 26 C *-C(=O)-O-Car 1.360 1.359 0.01 I 1.355 1.367 40 12 in anhydrides: O=C-O-C=O 1.386 1.386 0.011 1.379 1.393 70 in ring systems: furan (01-C2,01-C5) 1.368 1.369 0.015 1.359 1.377 125 isoxazole (01-C5) 1.354 1.354 0.010 1.345 1.360 9 p-lactones: C*-C(=O)-0-C* 1.359 1.359 0.013 1.348 1.371 4 13 y-lactones: C*-C(=O)-0-C* 1.350 1.349 0.012 1.342 1.359 110 12 6-lactones: C*-C(=O)-0-C* 1.339 1.339 0.016 1.332 1.347 27 12 Car-O( 2) in phenols: Car-OH 1.362 1.364 0.015 1.353 1.373 55 1 in aryl alkyl ethers: Cur-O-C* 1.370 1.370 0.011 1.363 1.377 920 29,32 J. CHEM.SOC. PERKIN TRANS. 11 1987 S13 Table (continued) Bond Substructure d rn d 41 4u n Note Car-O(2) in diary1 ethers: Car-O-Car 1.384 1.381 0.014 1.375 1.391 132 CspZ=O(1 ) in esters: Car-O-C(=O)-C* in aldehydes and ketones: 1.401 1.401 0.010 1.394 1.408 40 12 C*-CH=O 1.192 1.192 0.005 1.188 1.197 7 (C *),-Go 1.210 1.210 0.008 1.206 1.215 474 5 (C#),-C=Oin cyclobutanones 1.198 1.198 0.007 1.194 1.204 12 in cyclopentanones 1.208 1.208 0.007 1.203 1.212 155 in cyclohexanones c=c-c=o 1.21 1 1.222 1.21 1 1.222 0.009 0.010 1.207 1.216 1.216 1.229 312 225 (C=c),-c=O 1.233 1.229 0.010 1.226 1.242 28 Car-C=O 1.221 1.218 0.014 1.212 1.229 85 (Car),-C=O 1.230 1.226 0.01 5 1.220 1.238 66 C=O in benzoquinones 1.222 1.220 0.013 1.211 1.231 86 H-C 'v 0,-(formate) delocalized double bonds in carboxylate anions: c*-cN 0,- 1.242 1.254 1.243 1.253 0.012 0.010 1.234 1.247 1.252 1.26 1 24 114 w-c N 0,- 1.250 1.248 0.01 7 1.238 1.261 52 Car-C N 0,- 1.255 1.253 0.010 1.249 1.262 22 HOOC-C N 0,-(hydrogen oxalate) -0,N C-C = 0,-(oxalate) 1.243 1.251 1.247 1.251 0.01 5 0.007 1.232 1.248 1.256 1.254 26 18 in carboxylic acids (X-COOH) C*-C(=O)-OH 1.214 1.214 0.019 1.203 1.224 175 CX-C(=O)-OH Car-C(=O)-OH in esters: 1.229 1.226 1.226 1.223 0.017 0.020 1.218 1.21 1 1.237 1.24 1 22 75 c*-C(=O)-0-c* CX-C(=O)-0-c * Car-C(=O)-O-C* 1.196 1.199 1.202 1.196 1.198 1.201 0.010 0.009 0.009 1.190 1.193 1.196 1.202 1.203 1.207 551 113 218 12 12 c*-c(=o)-o-c=c 1.190 1.190 0.014 1.184 1.198 26 C *-C(=O)-O-Car 1.187 1.188 0.01 1 1.181 1.195 40 12 in anhydrides: O=C-O-C=O in p-lactones: C*-C(=O)-0-C* y-lactones: C*-C(=O)-0-C* 1.187 1.193 1.201 1.187 1.193 1.202 0.010 0.006 0.009 1.184 1.187 1.196 1.193 1.198 1.206 70 4 109 13 12 6-lactones: C*-C(=O)-0-C* in amides: 1.205 1.207 0.008 1.201 1.209 27 12 NH,-C(-C*)=O 1.234 1.233 0.012 1.225 1.243 32 14 (C*-)(C*,H-)N-C(-C*W p-lactams: C*-NH-C=O 1.231 1.198 1.231 1.200 0.012 0.012 1.224 1.193 1.238 1.204 378 23 14 13 y-lactams: C *-NH-C=O 1.235 1.235 0.008 1.232 1.240 20 13 C*-N(-C*)-C=O 6-lactams: 1.225 1.226 0.01 1 1.217 1.233 15 13 C *-NH-C=O 1.240 1.241 0.003 1.237 1.243 6 14 C *-N(-C *)-C=O 1.233 1.233 0.007 1.229 1.239 15 14 in ureas: Csp3-P( 4) Csp3-P( 3) Car-P(4) (N HI2 1,-C=O C(C#),-NI 2-c=O (C#-NH) 2-C=O C3-P+-C* C2-P(=O)-CH 3 C,-P(=O)-CH,-C C ,-P(=O)-CH-C 2 c,-P( =o)-c-c3 C,-P(=O)-C* (overall) c,-P-c* C3-P+-Car C,-P(=O)-Car Ph3-P=N +=P-Ph3 1.256 1.241 1.230 1 .800 1.791 1.806 1.821 1.841 1.813 1.855 1.793 1.801 1.795 1.256 1.237 1.230 1.802 1.790 1.806 1.821 1.842 1.811 1.857 1.792 1.802 1.795 0.007 0.01 1 0.007 0.015 0.006 0.009 0.009 0.008 0.01 7 0.019 0.01 1 0.01 1 0.008 1.249 1.235 1.224 1.790 1.786 1.801 1.815 1.835 1.800 1.840 1.786 1.796 1.789 1.261 1.245 1.234 1.812 1.795 1.813 1.828 1.847 1.822 1.870 1.800 1.807 1.800 24 13 20 35 10 45 15 14 84 23 276 98 197 25,26 25 25,27 33 Car-P( 3) Csp3-S(4) C,-P-Car (N -),P-Car (PN N aromatic) C*SO,-C (C* = CH, excluded) C*S02-C (overall)c*-so,-0-x C*-SO ,-N-X, 1.836 1.795 1.786 1.779 1.745 1.758 1.837 1.793 1.782 1.778 1.744 1.756 0.010 0.01 1 0.018 0.020 0.009 0.018 1.830 1.788 1.774 1.764 1.738 1.746 1.844 1.803 1.797 1.790 1.754 1.773 102 43 75 94 7 17 34 34 csp3-S( 3) C*-S(=O)-C (C* = CH3 excluded) C*S(=O)-C (overall) CH 343 +-X2 1.818 1.809 1.786 1.814 1.806 1.787 0.024 0.025 0.007 1.802 1.793 1.779 1.829 1.820 1.792 69 88 21 Csp3-S( 2) C*S+-X, (C* = CH, excluded) C*-S+-X, (overall) C*SH CH3-S-C* 1.823 1.804 1.808 1.789 1.820 1.794 1.805 1.787 0.016 0.025 0.010 0.008 1.812 1.788 1.800 1.784 1.834 1.820 1.819 1.794 18 41 6 9 S14 J.CHEM. SOC. PERKIN TRANS. II 1987 Table (continued) Bond Substructure d m B 41 4" n Note Csp3-S(2) C-CH,-S-C* C2-CH-S-C* 1.817 1.819 1.816 1.819 0.013 0.01 1 1.808 1.811 1.824 1.825 92 32 c,-c-S-c* 1.856 1.860 0.01 1 1.854 1.863 26 C*S-C* (overall) in thiirane 1.819 1.834 1.817 1.835 0.019 0.025 1.809 1.810 1.827 1.858 242 4 9 Csp2-S(2) in thietane: see ZCMXSP (1.817, 1.844) in tetrahydrothiophene in tetrahydrothiopyran c,-c-S-s-x C*-S-S-X (overall) c=c-s-c* C=C-S-C=C (in tetrathiafulvalene) C-CH2-S-S-X 1.827 1.823 1.823 1.863 1.833 1.751 1.741 1.826 1.821 1.820 1.865 1.828 1.755 1.741 0.018 0.014 0.014 0.015 0.022 0.017 0.01 1 1.81 1 1.812 1.813 1.848 1.818 1.740 1.733 1.837 1.832 1.832 1.878 1.848 1.764 1.750 20 24 41 11 59 61 88 C=C-S-C=C ox-S-C# (in thiophene) 1.712 1.762 1.712 1.759 0.01 3 0.018 1.703 1.747 1.722 1.778 60 20 Car-S(4) Car-SO,-C Car-SO,-O-X 1.763 1.752 1.764 1.750 0.009 0.008 1.756 1.749 1.769 1.756 96 27 Car-SO 2-N-X 2 1.758 1.759 0.013 1.749 1.765 106 35 Car-S( 3) Car-S(=O)-C Car-S+-X, 1.790 1.778 1.790 1.779 0.010 0.010 1.783 1.771 1.798 1.787 41 10 Car-S( 2) Car-S-C* Car-scar 1.773 1.768 1.774 1.767 0.009 0.010 1.765 1.762 1.779 1.774 44 158 Car-%Car Car-S-S-X (in phenothiazine) 1.764 1.777 1.764 1.777 0.008 0.012 1.760 1.767 1.769 1.785 48 47 csp1-S( 2) Csp'-S( 1) Csp2=S(1) N&-S-X (NX-S) -(C*),-C=.S: see IPMUDS (1.599) (Car),-C=S: see CELDOM (1.61 1) (X),-C=S (X = C,N,O,S) 1.679 1.630 1.671 1.683 1.630 1.675 0.026 0.014 0.024 1.645 1.619 1.656 1.698 1.641 1.689 10 14 245 Csp3-Se Csp2-Se(2) Car-Se(3) X,N-C(=S)-S-X N-C( S), (X,N),-C=S (t hioureas) C#-Se C=C-Se-CX (in tetraselenafulvalene) Ph3-Se+ 1.660 1.681 1.720 1.970 1.893 1.930 1.660 1.684 1.72 1 1.967 1.895 1.929 0.016 0.020 0.012 0.032 0.01 3 0.006 1.648 1.669 1.709 1.948 1.882 1.924 1.674 1.693 1.731 1.998 1.902 1.936 38 96 20 21 32 13 Csp3-Si(5) Csp3-Si(4) C#-Si --X4 CH,Si-X, 1.874 1.857 1.876 1.857 0.015 0.018 1.859 1.848 1.884 1.869 9 552 C*-Si-X3 (C* = CH, excluded) 1.888 1.887 0.023 1.872 1.905 124 C*-Si-X3 (overall) 1.863 1.861 0.024 1.850 1.875 68 1 Car-Si(4) Cspl-Si(4) Csp3-Te Car-Si-X, CS-Si-X , C#-Te 1.868 1.837 2.158 1.868 1.840 2.159 0.014 0.012 0.030 1.857 1.824 2.128 1.878 1.849 2.177 178 8 13 Car-Te Car-Te 2.116 2.115 0.020 2.104 2.130 72 Csp2=Te Cl-Cl see CEDCUJ (2.044) see PHASCL (2.306, 2.227) Cl-I see CMBIDZ (2.563), HXPASC (2.541, 2.513), METAMM (2.552), BQUINI (2.416, 2.718) Cl-N c1-O( 1) see BECTAE (1.743-1.757), in ClO, BOGPOC (1.705) 1.414 1.419 0.026 1.403 1.431 252 CI-P (N -),P-CI (N -N P aromatic) 1.997 1.994 0.015 1.989 2.004 46 Cl-s CI-P (overall) CI-S (overall) see also longer bonds in CILSAR (2.283), BIHXIZ (2.357), CANLUY (2.749) 2.008 2.072 2.00 1 2.079 0.035 0.023 1.986 2.047 2.028 2.09 1 111 6 CI-Se see BIRGUE10, BIRHAL10, CTCNSE C1-Si(4) (2.234-2.851) CI-Si-X, (monochloro) 2.072 2.075 0.009 2.066 2.078 5 CI,-Si-X, and C1,-Si-X 2.020 2.012 0.015 2.007 2.036 5 C1-Te Cl-Te in range 2.34-2.60 2.520 2.515 0.034 2.493 2.537 22 36 see also longer bonds in BARRIV, BOJPUL, F-N(3) F-P(6) F-P(3) CETUTE, EPHTEA, OPNTEClO (2.73-2.94) F-N-C2 and F,-N-C in hexafluorophosphate, PF,- (N -),P-F (N 2: P aromatic) 1.406 1.579 1.495 1.404 1.587 1.497 0.016 0.025 0.016 1.395 1.563 1.48 1 1.416 1.598 1.510 9 72 10 F-S 43 observations in range 1.409-1.770 variety of environments; F-S(6) in in a wide F-Si(6) F-Si(5) F-Si(4) F,-SO,-C, (see FPSULF10, BETJOZ) F-S(4) in F,-S(=O)-N (see BUDTEZ) in SiF,,-F-Si --X4 FSi-X, 1.640 1.527 1.694 1.636 1.588 1.646 1.528 1.701 1.639 1.587 0.01 1 0.004 0.013 0.035 0.014 1.626 1.524 1.677 1.602 1.581 1.649 1.530 1.703 1.657 1.599 6 24 6 10 24 37 J.CHEM. SOC. PERKIN TRANS. II 1987 S15 Table (continued) Bond Substructure d m 0 41 4" n Note F-Te see CUCPIZ (F-Te(6) = 1.942, 1.937), FPHTEL (F-Te(4) = 2.006) H-N(4) X3-N+-H 1.033 1.036 0.022 1.026 1.045 87 21 H-N( 3) X2-N-H 1.009 1.010 0.019 0.997 1.023 95 21 H-O( 2) in alcohols C*-O-H 0.967 0.969 0.010 0.959 0.974 63 21 Cfl-O-H 0.967 0.970 0.010 0.959 0.974 73 21 in acids OX-O-H 1.015 1.017 0.017 1.001 1.031 16 21,38 1-1 in I,- 2.917 2.918 0.01 1 2.907 2.927 6 I-N see BZPRIB, CMBIDZ, HMTITI, HMTNTI, IFORAM, IODMAM (2.042-2.475) 1-0 X-1-0 (see BZPRIB, CAJMAB, IBZDACl1) 2.144 2.144 0.028 2.127 2.164 6 I-P(3) I-s for 10,-see BOVMEE (1.829-1.912) see CEHKAB (2.490-2.493) see DTHIBRlO (2.687), ISUREAlO (2.629), t I-Te-X, BZTPPI (3.251) 2.926 2.928 0.026 2.902 2.944 8 X,-N+-No-X2 (No planar) 1.414 1.414 0.005 1.412 1.418 13 N,, N, pyramidal N, pyramidal, N, planar (C)(C,H)-Na-N,-(C)(C,H) 1.454 1.420 1.452 1.420 0.02 1 0.015 1.444 1.407 1.457 1.433 44 68 5,39 40 40 N,, N, planar overall 1.401 1.425 1.401 1.425 0.018 0.027 1.384 1.407 1.418 1.443 40 139 40 N(3)-N(2) in pyrazole (Nl-N2) in pyridazinium (N1' 5N2) 1.366 1.350 1.366 1.349 0.019 0.010 1.350 1.345 1.375 1.361 20 7 N(2) 1N(2) N zN (aromatic) in pyridazine with C,H as ortho substituents 1.304 1.300 0.019 1.287 1.326 6 with N,Cl as orrho substituents 1.368 1.373 0.01 1 1.362 1.375 9 N(2)=N(2) C#-N=N-C# cis 1.245 1.244 0.009 1.239 1.252 21 trans 1.222 1.222 0.006 1.218 1.227 6 (overall) 1.240 1.241 0.012 1.230 1.251 27 Car-N=N-Car 1.255 1.253 0.016 1.247 1.262 13 X-N=N=N (azides) 1.216 1.226 0.028 1.202 1.237 19 X-N=N=N (azides) 1.124 1.128 0.015 1.114 1.137 19 (C,H),-N-OH (Nsp2:planar) 1.396 1.394 0.012 1.390 1.40 1 28 C2-N-O-C (Nsp3: pyramidal) 1.463 1.465 0.012 1.457 1.468 22 (Nsp2:planar) 1.397 1.394 0.01 1 1.388 1.409 12 in furoxan (N2-01) 1.438 1.436 0.009 1.430 1.447 14 (C -),N+-O-in pyridine N-oxides in furoxan (+N2-06-) in oximes 1.304 1.234 1.299 1.234 0.015 0.008 1.291 1.228 1.316 1.240 11 14 (C#),-C=N-O H 1.416 1.418 0.006 1.416 1.420 7 (H)(Csp2)-C=N-0H 1.390 1.390 0.01 1 1.380 1.401 20 (C#)( Csp2)-C=N-OH 1.402 1.403 0.010 1.393 1.410 18 (Csp2)2-C=N-OH 1.378 1.377 0.017 1.365 1.393 16 (C,H),-C=N-OH (overall) 1.394 1.395 0.018 1.379 1.408 67 in furazan (01-N2, Ol-N5) 1.385 1.383 0.01 3 1.378 1.392 12 in furoxan (01-N5) in isoxazole (Ol-N2) 1.380 1.425 1.380 1.425 0.01 1 0.010 1.370 1.417 1.388 1.434 14 9 N(3)=0(1) in nitrate ions NO3- 1.239 1.240 0.020 1.227 1.251 105 in nitro groups C*-N02 1.212 1.214 0.012 1.206 1.22 1 84 C#-NO2 1.210 1.210 0.011 1.203 1.218 251 Cur- NO, 1.217 1.218 0.01 1 1.211 1.215 1116 C-N02 (overall) 1.218 1.219 0.013 1.210 1.226 1733 X,-P(=X)-NX, Nsp': planar Nsp3: pyramidal 1.652 1.683 1.651 1.683 0.024 0.005 1.634 1.680 1.670 1.686 205 6 (overall) 1.662 1.662 0.029 1.639 1.682 358 subsets of this group are: O,-P(=S)-NX, C-P(=S)-(NX,), 0-P(=S)-( NX 2)2 P(a)-(NX2)3-NX-P(-X)-NX-P(-X)-(P,N2 ring) -NX-P(=S)-NX-P(=S)-(P2N, ring) 1.628 1.691 1.652 1.663 1.730 1.697 1.624 1.694 1.654 1.668 1.72 1 1.697 0.015 0.018 0.014 0.026 0.017 0.015 1.615 1.678 1.642 1.640 1.716 1.690 1.634 1.703 1.664 1.679 1.748 1.703 9 28 28 78 20 44 N(2)=P(4) in P-substituted phosphazenes: (N -),P-N (amino) (aziridinyl) Ph,-P=N+=P-Ph, 1.637 1.672 1.57 1 1.638 1.674 1.573 0.014 0.010 0.013 1.625 1.665 1.563 1.65 1 1.676 1.580 16 15 66 S16 J.CHEM. SOC. PERKIN TRANS. 11 1987 Table (continued) Bond Substructure d rn 0 41 4" n Note N(2) 'v P(3) N(Z)=P(3) Ph,-P=N-C,S N 2: P aromatic in phosphazenes in PzN2:S 1.599 1.582 1.604 1.597 1.582 1.606 0.01 8 0.019 0.009 1.580 1.571 1.594 1.615 1.594 1.612 7 126 36 N(3)-S(4) C-SO,-NH 2 C-SO,-NH-C# 1.600 1.63 3 1.601 1.633 0.012 0.019 1.591 1.615 1.610 1.652 14 47 35 35 N(3)-S(2) N(2)-S(2)N(2) 1: S(2) N(2)=S(2) N( 3)-Se C-SO ,-N-C( #)2 C-S-NX, Nsp': planar (for Nsp3 pyramidal see MODIAZ: 1.765) X-S-NX, Nsp': planar N 'v S aromatic in P 2: N 'v S NS in N=S=N and N=S=S see COJCUZ (1.830), DSEMORlO (1.846, C=N-S-X 1.852), MORTRSlO (1.841) 1.642 1.710 1.707 1.656 1.560 1.541 1.64 1 1.707 1.705 1.663 1.558 1.546 0.024 0.019 0.012 0.027 0.011 0.022 1.623 1.698 1.699 1.632 1.554 1.52 1 1.659 1.722 1.715 1.677 1.563 1.558 38 22 30 36 37 37 35 23 23 N( 2)-Se N(2)=Se N(3)-Si(5 see SEBZQI (1.805), NAPSEZlO (1.809, 1.820) see CISMUM (1.790, 1.791) see DMESIPO1, BOJLER, CASSAQ, CASYOK, CECXEN, CINTEY, CIPBUY, N(3)-Si(4 FMESIB, MNPSIL, PNPOSI (1.973-2.344) X,-Si-NX, (overall) subsets of this group are: X ,-Si-NHX 1.748 1.714 1.746 1.719 0.022 0.014 1.735 1.702 1.757 1.727 170 16 N(2)-Si(4) N-Te X,-Si-NX-Si-X, acyclic N-Si-N in 4-membered rings N-Si-N in 5-membered rings X,-Si-N --Si-X, see ACLTEP (2.402), BIBLAZ (1.980), 1.743 1.742 1.741 1.711 1.744 1.742 1.742 1.712 0.016 0.009 0.019 0.019 1.731 1.735 1.726 1.693 1.755 1.748 1.749 1.729 45 53 33 15 CESSAU (2.023) C *-0-0-C*,H ~(00)= 7&85" ~(00)ca.180" overall 1.464 1.482 1.469 1.464 1.480 1.47 1 0.009 0.005 0.012 1.458 1.478 1.46 1 1.472 1.486 1.478 12 5 17 0s-0-0-C=O see ACBZPOOl (1.446), CEYLUN (1.452), CIMHIP (1.454) Si-0-0-Si 1.496 1.499 0.005 1.490 1.499 10 x-P-( OX), trigonal bipyramidal: 41 axial 1.689 1.685 0.024 1.675 1.712 20 equatorial 1.619 1.622 0.024 1.604 1.628 20 square pyramidal 1.662 1.66 1 0.020 1.649 1.673 28 C-0-P( % 0), -(C-O),-P( 2: o),-(H-O),-P( =0)2-(C#-O),-P=O 1.62 1 1.560 1.608 1.558 1.622 1.56 1 1.607 1.554 0.007 0.009 0.013 0.01 1 1.615 1.555 1.599 1.550 1.628 1.566 1.615 1.564 12 16 16 30 (Car-O),-P=O 1.587 1.588 0.014 1.572 1.599 19 X-O-P(d)-(C,N), (X-0) 2-P(=O)-(C,N) (N -),P-O-C (N 'v P aromatic) C-0-P( 'v O),,-(declocalized) (H-O),-P( 1:O),-(delocalized) (C-O),-P( 'v 0)2-(delocalized) (C-O),-P=O c,-P=O 1.590 1.571 1.573 1.513 1.503 1.483 1.449 1.489 1.585 1.572 1.573 1.512 1 SO3 1.485 1.448 1.486 0.016 0.013 0.01 1 0.008 0.005 0.008 0.007 0.010 1.577 1.563 1.563 1.508 1.499 1.474 1.446 1.48 1 1.60 1 1.579 1.584 1.518 1.508 1.490 1.452 1.496 33 70 16 42 16 16 18 72 N3-P- 1.46 1 1.462 0.014 1.449 1.470 26 (C),(N)-P=O(C"(O)-P=O (C,N)(O),-P=Oc-0-so,-c 1.487 1.467 1.457 1.577 1.489 1.465 1.458 1.576 0.007 0.007 0.009 0.015 1.479 1.462 1.454 1.566 1.493 1.472 1.462 1.584 5 33 35 41 C-O-SO,-CH, 1.569 1.569 0.013 1.556 1.582 7 C-0-SO,-Car 1.580 1.578 0.015 1.571 1.588 27 c-so,-c X-SOZ-NX, 1.436 1.428 1.437 1.428 0.010 0.010 1.431 1.422 1.442 1.434 316 326 42 c-so2-0-cCSO,-N-(C,H), 1.430 1.423 1.430 1.423 0.009 0.008 1.425 1.418 1.435 1.428 206 82 in SO,' - 1.472 1.473 0.013 1.463 1.481 104 O(1)=S(3) c-S(=O)-c 1.497 1.498 0.0 13 1.489 1.505 90 5 0-Se see BAPPAJ, BIRGUE10, BIRHAL10, CXMSEO, DGLYSE, SPSEBU (1.597 for 0-==to 1.974 for 0-Se) 0(2)-Si(5) 0(2)-Si(4) (X-O),Si-(N)(C) X,-Si-0-X (overall) 1.663 1.63 1 1.658 1.630 0.023 0.022 1.650 1.617 1.665 1.646 21 191 J.CHEM. SOC. PERKIN TRANS. 11 1987 S17 Table (continued) Bond Substructure d m 0 41 4" n Note 0(2)-Si(4) subsets of this group are: X,-Si-0-C# 1.645 1.647 0.012 1.634 1.652 29 X,-Si-0-Si-X, 1.622 1.625 0.014 0.614 1.631 70 X,-Si-0-0-Si-X, 1.680 1.676 0.008 1.673 1.688 10 O(2)-Te(6) (X-O),-Te 1.927 1.927 0.020 1.908 1.942 16 0(2)-Te(4) P(4)-P(4) P(4)-P(3) P(3)-P(3)P(4)=P(4) (X-O),-Te-X, x,-P-P-x, x,-P-P-x, see CECHEX (2.197), COZPIQ (2.249) see BUTSUE (2.054) 2.133 2.256 2.2 14 2.136 2.259 2.210 0.054 0.025 0.022 2.078 2.243 2.200 2.177 2.277 2.224 12 6 41 P(3)=P(3) see BALXOB (2.034) P(4)=S( 1) c,-P=S 1.954 1.952 0.005 1.950 1.957 13 P(4)=Se(1) P(3)-Si( 4) "),(C)-P=S(N,O),-P=S x,-P=se X,-P-Si-X,: 3-and 4-rings 1.922 1.913 2.093 2.264 1.924 1.914 2.099 2.260 0.014 0.014 0.019 0.019 1.913 1.906 2.075 2.249 1.927 1.92 1 2.108 2.283 26 50 12 22 excluded (see BOPFER, BOPFIV, CASTOF10, COZVIW: 2.201-2.317) P(4)=Te(1 ) S(2)-S(2) S(2)-S( 1) S-Se(4) see MOPHTE (2.356), TTEBPZ (2.327)c-S-s-c T(SS) = 75-105" T(SS) = 0-20" (overall) in polysulphide chain-S-S-S- see BUWZUO (2.264, 2.269) X-N=S-S 2.03 1 2.070 2.048 2.05 1 1.897 2.029 2.068 2.045 2.050 1.896 0.015 0.022 0.026 0.022 0.012 2.02 1 2.057 2.028 2.037 1.887 2.038 2.077 2.068 2.065 1.908 46 28 99 126 5 S-Se( 2) S(2)-Si(4) S(2)-Te Se(2)-Se( 2) Se(2)-Te(2) Si(4)-Se(4) X-Se-S (any) X,-Si-S-X X-S-Te (any) X=S-Te (any) x-se-se-x see BAWFUA, BAWGAH (2.524-2.561) X,-SiSi-X, 3-membered rings excluded: 2.193 2.145 2.405 2.682 2.340 2.359 2.195 2.138 2.406 2.686 2.340 2.359 0.015 0.020 0.022 0.035 0.024 0.012 2.174 2.130 2.383 2.673 2.315 2.349 2.207 2.158 2.424 2.694 2.361 2.366 9 19 10 28 15 42 t see CIHRAM (2.511) Te-Te see CAHJOK (2.751, 2.704) Appendix 1.(Footnotes to Table) 1. Sample dominated by B-CH,. For longer bonds in B--CH, see LITMEBlO [B(4)-CH3 = 1.621-1.644A1. 2. p(lc)-p(n) Bonding with Bsp2 and Nsp2 coplanar (TBN = 0 i-15") predominates. See G. Schmidt, R. Boese, and D. Blaser, Z. Naturforsch., 1982, 37b, 1230.3. 84 observations range from 1.38 to 1.61 A and individual values depend on substituents on B and 0. For a discussion of borinic acid adducts see S. J. Rettig and J. Trotter, Can. J. Chem., 1982, 60, 2957. 4. See M. Kaftory in 'The Chemistry of Functional Groups. Supplement D: The Chemistry of Halides, Pseudohalides, and Azides' eds. S. Patai and Z. Rappoport, Wiley: New York, 1983, Part 2, ch. 24. 5. Bonds which are endocyclic or exocyclic to any 3-or 4-membered rings have been omitted from all averages in this section. 6. The overall average given here is for Csp3-Csp3 bonds which carry only C or H substituents. The value cited reflects the relative abundance of each 'substitution' group. The 'mean of means' for the 9 subgroups is 1.538 (0 = 0.022) A.7. See F. H. Allen, (a) Acta Crystallogr., 1980, B36, 81; (b) 1981, B37, 890. 8. See F. H. Allen, Acta Crystallogr., 1984, B40, 64. 9. See F. H. Allen, Tetrahedron, 1982, 38, 2843. 10. See F. H. Allen, Tetrahedron, 1982, 38, 645. 1 1. Cyclopropanones and cyclobutanones excluded. 12. See W. B. Schweizer and J. D. Dunitz, Helv. Chim. Acta, 1982, 65, 1547. 13. See L. Norskov-Lauritsen, H.-B. Burgi, P. Hoffmann, and H. R. Schmidt, Helv. Chim. Acta, 1985, 68, 76. 14. See P. Chakrabarti and J. D. Dunitz, Helv. Chim. Acta, 1982, 65, 1555. 15. See J. L. Hencher in 'The Chemistry of the C-=C Triple Bond,' ed. S. Patai, Wiley, New York, 1978, ch. 2. 16. Conjugated: torsion angle about central C-C single bond is 0 _+ 20" (cis) or 180 f20" (trans).17. Unconjugated: torsion angle about central C-C single bond is 2&-160". 18. Other conjugative substituents excluded. 19. TCNQ is tetracyanoquinodimethane. 20. No difference detected between C2 2: C3 and C3 1: C4 bonds. 21. Derived from neutron diffraction results only. 22. Nsp3: pyramidal; mean valence angle at N is in range 108-1 14". 23. Nsp2: planar; mean valence angle at N is 2 117.5". 24. Cyclic and acyclic peptides. 25. See R. H. Blessing, J. Am. Chem. SOC., 1983, 105, 2776. 26. See L. Lebioda, Acta Crystallogr., 1980, B36, 271. 27. n = 3 or 4, i.e. tri- or tetra-substituted ureas. 28. Overall value also includes structures with mean valence angle at N in the range 115-1 18".29. See F. H. Allen and A. J. Kirby, J. Am. Chem. SOC.,1984, 106, 6197. 30. See A. J. Kirby, 'The Anomeric Effect and Related Stereoelectronic Effects at Oxygen,' Springer, Berlin, 1983. 31. See B. Fuchs, L. Schleifer, and E. Tartakovsky, Noun J. Chim., 1984, 8, 275. S18 J. CHEM. SOC. PERKIN TRANS. 11 1987 32. See S. C. Nyburg and C. H. Faerman, J. Mol. Struct., 1986, 140, 347. 33. Sample dominated by P-CH, and P-CH,-C. 34. Sample dominated by C* = methyl. 35. See A. Kalman, M. Czugler, and G. Argay, Acta Crystallogr., 1981, B37, 868. 36. Bimodal distribution resolved into 22 'short' bonds and 5 longer outliers. 37. All 24 observations come from BUDTEZ.38. 'Long' O-H bonds in centrosymmetric 0 ---H ---0 H-bonded dimers are excluded. 39. N-N bond length also dependent on torsion angle about N-N bond and on nature of substituent C atoms; these effects are ignored here. 40. N pyramidal has average angle at N in range 100-113.5"; N planar has average angle of 2 117.5". 41. See R. R. Holmes and J. A. Deiters, J. Amer. Chem. SOC., 1977,99, 3318. 42. No detectable variation in S=O bond length with type of C-substituent. Appendix 2. Short-form references to individual CSD entries cited by reference code in the Table. A full list of CSD bibliographic entries is given in SUP 56701. ACBZPOOl J. Am. Chem. SOC., 1975, 97, 6729. CISTED Z. Anorg. Allg. Chem., 1984, 511, 95.ACLTEP ASAZOC J. Organomet. Chem., 1980, 184,417. Dokl. Akad. Nauk SSSR, 1979, 249, 120. CIWYIQ CIYFOF Inorg. Chem., 1984, 23, 1946. Znorg. Chem., 1984, 23, 1790. BALXOB J. Am. Chem. SOC., 1981, 103,4587. CMBIDZ J. Org. Chem., 1979, 44, 1447. BAPPAJ BARRIV Inorg. Chem., 1981, 20, 3071. Acta Chem. Scand., Ser. A, 1981, 35, 443. CODDEE CODDII Z. Naturforsch., Teil B, 1984, 39, 1257. Z. Naturforsch., Teil B, 1984, 39, 1257. BAWFUA BAWGAH BECTAE BELNIP Cryst. Struct. Commun., 1981, 10, 1345. Cryst. Struct. Commun., 1981, 10, 1353. J. Org. Chem., 1981, 46, 5048, 1981. Z. Naturforsch., Teil B, 1982, 37, 299. COFVOI COJCUZ COSDIX COZPIQ Z. Naturforsch., Teil B, 1984, 39, 1027. Chem. Ber., 1984, 117, 2686. Z. Naturforsch., Teil B, 1984, 39, 1344.Chem. Ber., 1984, 117, 2063. BEMLIO Chem. Ber., 1982, 115, 1126. COZVIW Z. Anorg. Allg. Chem., 1984, 515, 7. BEPZEB BETJOZ Cryst. Struct. Commun., 1982, 11, 175. J. Am. Chem. SOC., 1982, 104, 1683. CTCNSE CUCPIZ J, Am. Chem. SOC., 1980, 102, 5430. J. Am. Chem. SOC., 1984, 106, 7529. BETUTE 10 Acta Chem. Scand., Ser. A, 1976, 30, 719. CUDLOC J. Cryst. Spectrosc., 1985, 15, 53. BIBLAZ Zh. Strukt. Khim., 1981, 22, 118. CUDLUI J. Cryst. Spectrosc., 1985, 15, 53. BICGEZ BIHXIZ Z. Anorg. Allg. Chem., 1982, 486, 90. J. Chem. SOC., Chem. Commun., 1982,982. CUGBAH CXMSEO Acta Crystallogr., Sect. C, 1985, 41, 476. Acta Crystallogr., Sect. B, 1973, 29, 595. BIRGUElO Z. Naturforsch., Teil B, 1983, 38, 20. DGLYSE Acta Crystallogr., Sect.B, 1975, 31, 1785. BIRHALlO Z. Naturforsch., Teil B, 1982, 37, 1410. DMESIPOl Acta Crystallogr., Sect. C, 1984, 40, 895. BIZJAV BOGPOC J. Organomet. Chem., 1982, 238, C1. Z. Naturforsch., Teil B, 1982, 37, 1402. DSEMORlO DTHIBRlO J. Chem. Soc., Dalton Trans., 1980, 628. Znorg. Chem., 1971, 10, 697. BOGSUL Z. Naturforsch., Teil B, 1982, 37, 1230. EPHTEA Inorg. Chem., 1980, 19, 2487. BOJLER Z. Anorg. Allg. Chem., 1982, 493, 53. ESEARS J. Chem. SOC. C, 1971, 1511. BOJPUL Acta Chem. Scand., Ser. A, 1982,36, 829. ETEARS J. Chem. SOC. C, 1971, 1511. BOPFER Chem. Ber., 1983, 116, 146. FMESIB J. Organomet. Chem., 1980, 197, 275. BOPFIV Chem. Ber., 1983,116, 146. FPHTEL J. Chem. SOC., Dalton Trans., 1980, 2306. BOVMEE BQUINI BTUPTE BUDTEZ Acta Crystallogr., Sect.B, 1982, 38, 1048. Acta Crystallogr., Sect. B, 1979, 35, 1930. Acta Chem. Scand., Ser. A, 1975, 29, 738. Z. Naturforsch., Ted B, 1983, 38, 454. FPSULFlO HCLENElO HMTITI HMTNTI J. Am. Chem. Soc., 1982, 104, 1683. Acta Crystallogr., Sect. B, 1982, 38, 3139. Acta Crystallogr., Sect. B, 1975, 31, 1505. Z. Anorg. Allg. Chem., 1974, 409, 237. BUPSIBlO Z. Anorg. Allg. Chem., 1981, 474, 31. HXPASC J. Chem. SOC., Dalton Trans., 1975, 1381. BUSHAY Z. Naturforsch., Teil. B, 1983, 38, 692. IBZDAC 1 1 J. Chem. SOC., Dalton Trans., 1979, 854. BUTHAZlO Inorg. Chem., 1984, 23, 2582. IFORAM Monatsh. Chem., 1974, 105, 621. BUTSUE BUWZUO BZPRIB BZTPPI CAHJOK J. Chem. SOC., Chem. Commun., 1983, 862. Acta Chem.Scand., Ser A, 1983, 37, 219. Z. Naturforsch., Teil B, 1981, 36, 922. Inorg. Chem., 1978, 17, 894. Znorg. Chem., 1983, 22, 1809. IODMAM IPMUDS ISUREAlO LITM EB 10 MESIAD Acta Crystallogr., Sect. B, 1977, 33, 3209. Acta Crystallogr., Sect. B, 1973, 29, 2128. Acta Crystallogr., Sect. B, 1972, 28, 643. J. Am. Chem. SOC., 1975,97, 6401. Z. Naturforsch., Teil B, 1980, 35, 789. CAJMAB CANLUY Chem. Z, 1983, 107, 169. Tetrahedron Lett., 1983, 24, 4337. METAMM MNPSIL Acta Crystallogr., 1964, 17, 1336. J. Am. Chem. SOC., 1969, 91,4134. CASSAQ CASTOF10 CASYOK J. Struct. Chem., 1983, 2, 101. Acta Crystallogr., Sect. C, 1984, 40, 1879. J. Struct. Chem., 1983, 2, 107. MODIAZ MOPHTE MORTRSlO J. Heterocycl. Chem., 1980, 17, 1217. Acta Chem. Scand., Ser. A, 1980, 34, 333.J. Chem. SOC., Dalton Trans., 1980, 628. CECHEX Z. Anorg. Allg. Chem., 1984, 508, 61. NAPSEZlO J. Am. Chem. SOC., 1980, 102, 5070. CECXEN J. Struct. Chem., 1983, 2, 207. NBBZAM Z. Naturforsch., Teil B, 1977, 32, 1416. CEDCUJ CEHKAB J, Org. Chern., 1983, 40, 5149. Z. Naturforsch., Teil B, 1984, 39, 139. OPIMAS OPNTEClO Aust. J. Chem., 1977, 30, 2417. J. Chem. SOC., Dalton Trans., 1982, 251. CELDOM CESSAU Acta Crystallogr., Sect. C, 1984, 40, 556. Acta Crystallogr., Sect. C, 1984, 40, 653. PHASCL PHASOCOl Acta Crystallogr., Sect. B, 1981, 37, 1357. Aust. J. Chem., 1975, 28, 15. CETTAW Chem. Ber., 1984, 117, 1089. PNPOSI J. Am. Chem. SOC., 1968, 90, 5102. CETUTE Acta Chem. Scand., Ser A, 1975, 29, 763. SEBZQI J. Chem. SOC., Chem.Commun., 1971, 325. CEYLUN Izv. Akad. Nauk SSSR, Ser. Khim., 1983,2744. SPSEBU Acta Chem. Scand., Ser. A, 1979, 33, 403. CIFZUM CIHRAM Acta Chem. Scand., Ser A, 1984, 38, 289. Angew. Chem., Int. Ed. Engl., 1984, 23, 302. TEACBR THINBR Cryst. Struct. Commun., 1974, 3, 753. J. Am. Chem. SOC., 1970, 92, 4002. CILRUK CILSAR J. Chem. SOC., Chem. Commun., 1984, 1023. J. Chem. SOC., Chem. Commun., 1984, 1021. TMPBTI TPASSN Acta Crystallogr., Sect. B, 1975, 31, 11 16. J. Chem. SOC., Dalton Trans., 1977, 514. CIMHIP CINTEY Acta Crystallogr., C, 1984, 40, 1458. Dokl. Akad. Nauk SSSR, 1984,274, 615. TPASTB TPHOSI Cryst. Struct. Commun., 1976, 5, 39. Z. Naturforsch., Teil B, 1979, 34, 1064. CIPBUY J. Struct. Chem., 1983, 2, 281. TTEBPZ Z. Naturforsch., Teil B, 1979, 34, 256.CISMUM Z. Naturforsch., Teil B, 1984, 39, 485. ZCMXSP Cryst. Struct. Commun., 1977, 6, 93. J. CHEM. SOC. PERKIN TRANS. 11 1987 S19 References 1 L. E. Sutton, ‘Tables of Interatomic Distances and Configuration in Molecules and Ions,’ Chemical Society Special Publication No. 11, Chemical Society, London, 1958. 2 L. E. Sutton, ‘Tables of Interatomic Distances and Configuration in Molecules and Ions,’ Chemical Society Special Publication No. 18, Chemical Society, London, 1965. 3 0. Kennard in ‘International Tables for X-Ray Crystallography,’ Kynoch Press, Birmingham, 1962, vol. 111, pp. 275-276. 4 F. H. Allen, S. Bellard, M. D. Brice, B. A. Cartwright, A. Doubleday, H. Higgs, T. Hummelink, B. G. Hummelink-Peters, 0. Kennard, W. D. S. Motherwell, J. R. Rodgers, and D. G. Watson, Acta Cryslallogr., 1979, B35, 2331. 5 0. Kennard, D. G. Watson, F. H. Allen, N. W. Isaacs, W. D. S. Motherwell, R. C. Pettersen, and W. G. Town, ‘Molecular Structures and Dimensions, vol. Al. Interatomic Distances 1960-1965,’ Oosthoek Utrecht, 1972. 6 M. D. Harmony, V. W. Laurie, R. L. Kuczkowski, R. H. Schwendemann, D. A. Ramsay, F. J. Lovas, W. J. Lafferty, and A. G. Maki, J. Phys. Chem. Ref: Data, 1979, 8, 619. 7 ‘Cambridge Crystallographic Data Centre User Manual,’ Cambridge University, 1978, 2nd edn. 8 R. Taylor and 0.Kennard, Acta Crystallogr., 1983, B39, 517. 9 R.Taylor and 0.Kennard, Acta Cryslallogr., 1985, A41, 85. 10 R. Taylor and 0. Kennard, J. Chem. Inf: Comp. Sci., 1986, 26, 28. 11 G. Bergerhoff, R. Hundt, R. Sievers, and I. D. Brown, J. Chem. Inf: Comp. Sci., 1983, 23, 66. Received 6th February 1987; Paper 7/194 0Copyright 1987 by The Royal Society of Chemistry

ISSN:1472-779X    

DOI:10.1039/P298700000S1

出版商:RSC    

年代:1987

数据来源: RSC