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The crystal structure of 1,4,7,14,17,20,28,35-octaoxa[2.23,29][7.718,34]-orthocyclophane and its multihydrated complex with potassium chloride |
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Journal of the Chemical Society, Perkin Transactions 2,
Volume 1,
Issue 1,
1981,
Page 1-11
Ian R. Hanson,
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摘要:
JOURNAL OF THE CHEMICAL SOCIETY PERKIN TRANSACTIONS ll Physical Organic Chemistry The Crystal Structure of I ~4#7,14,17,20,28,35-0ctao~a[23~29.21~~34117.71-orthocyclophane and its Multihydrated Complex with Potassium Chloride By Ian R. Hanson and Mary R. Truter," Molecular Structures Department, Rothamsted Experimental Station, Harpenden, Herts. AL5 2JQ Crystal structures of a bridged crown ether (I),systematically named in the title, and its complex with potassium chloride (11) have been determined by X-ray diffraction. Observations were collected on a four-circle diffracto- meter. Compound (I) is monoclinic, a = 11.539(2), b = 9.558(3), c = 22.802(7) A, p = 98.1 9(2)" with space group P2,lc. Compound (11) crystallises with eight complex cations [K(I)]+, eight chloride ions, and 44 water molecules in a monoclinic unit cell, a = 22.578(6), b = 17.162(5), c = 16.742(5) A, p = 99.48(2)' and space group /2/c.Full matrix refinement of (I) led to an R value of 0.066 for 1 775 observed reflections. The molecule has no symmetry, the conformation of the portion from O(1) to O(7) is unusual, unfavourable torsion angles may be correlated with inter-, but not with intra-molecular 0 * -HC contacts. Part of the structure exhibits disorder, one oxygen atom O(28) was allowed partial occupancy of two sites, and the benzene ring to which it is attached was allowed anisotropic vibration parameters as were all the oxygen atoms. The structure of (IT) consists of complex cations which have a non-crystallographic plane of symmetry.Co-ordination about the potassium ion approxi- mates to an end-capped trigonal prism, K-0 distances to the capping atoms (CH,-O-CH,) average 2.687 A, and those for the other atoms average 2.733 A. There are no interactions between the anions or water molecules and the potassium ions, or the eight oxygen atoms of the ligand. The cations are packed, with contacts of normal van der Waals distances, to form channels parallel to the c axis of the crystal. In these channels chloride ions, mainly disordered over two sites, and water molecules, also disordered, form networks which cannot be uniquely deter- mined. Full matrix refinement gave an R value of 0.104 for 2 138 observed reflections. In this the potassium ion and the carbon atoms of one benzene ring were allowed anisotropic vibration : the other atoms of the cation were allowed isotropic vibration parameters while the disordered atoms were all assumed to have mean square isotropic vibrations of 0.25 A2 and their occupation numbers were treated as parameters.A KECENT advance by our group in systematic study of with different salts are the same in the fingerprint region, the co-ordination chemistry of alkali and alkaline earth and indicate a conformation different from that of tlic metal cations has been the design and synthesis of novel free molecule. As shown in a preliminary communic- macrobicyclic polyetl~trs.~ Like the cryptates they ation stoiclieiometries other than 1 : 1 are possible for can form complexes with alkali metal salts having high large cations.The formation constants also showed that formation constants even in aqueous solution but, unlike substitution of two metliylene groups by a benzene ring the cryptatcs, there are no nitrogen atonis giving did not lead to a decrease in formation constant unlike sensitivity to pH. Further compounds in the series the usual behaviour of monocyclic crown ttlicrs,5 W'c have now been syiitlriesisetlt and their behaviour as reported there * the crystal structure of the complex of ligands is under investigation.3 the title compound (I) with potassium cliloride, and Characteristic features are that the conipounds them- showed the formula to be KCl(I)nH,O; tlie crystal selves are not soluble in water but are solubilised by contains discrete [K(I ' ) j catiws and disordered+ alkali metal salts, and the complexes crystallise with coluinns of water molecules and anions in sitcs of partial large and non-stoiclieiometric numbers of molecules of occupation.The structure is consistent with the con-water of crystallisation; even if the crystals are dried formation of the complex cation being independent of over sodium hydroxide in a desiccator, or in an oven, tlie anion. \ie now report the full results for tlie struc- they increase in weight while being weighed open to the ture analysis of tlie complex and, for coniparison, tlie atmosphere. crystal structure of the uncomplexed molecule wliicli , For a given molecule the i.r. spectra of (1 : 1) complexes as expected, does not have the same conformation. In fact it shows two conformations in the crystal, neither of which can be accurately determined because the crystal structure is a space average of them.For both compounds observations were collected on the same instrument so the experimental details are reported for the free ligand with those of the complex in paren- theses. EXPERIMENTAL Compound (I) was obtained from acetone as colourless needles, one of which, 0.15 x 0.2 x 0.45 mm elongated along the h axis, was used for intensity measurements. [It was difficult to find a good crystal of (11), the large rhombs tended to shatter when cut; a fragment 0.3 x 0.1 x 0.09 mm (elongated parallel to the a axis) was mounted on the diffractometer and found to give good diffraction with a small mosaic spread.] Unit cell dimensions and intensities were measured on an Enraf-Nonius CAD4 diffractometer with monochromated Rlo-K, radiation, A = 0.710 69 A (1 8, 10-lO m).Crystal Data.-(I), C2,H3,08, M = 494.6. Monoclinic, u = 11.539(2),b = 9.558(3),c = 22.802(7)A, (3 = 98.19(2)', 2U = 2 489(1) A3,I), = 1.32 g ~m-~,= 4, L), = 1.32 g ~m-~,F(000) = 104 8. Space group P2Jc uniquely deter- mined. M[C~ysfal Data.-(II), C~,H,,O,,KC~,TZH~O,= 659.2 (n = 5). Monoclinic, a = 22.578(6), h = 17.162(5), c = 16.742(5) A, p = 99.48(2)O, U = 6 398.7 .Pi3, D, 1.35(1) Zg ~m-~,= 8, D, (n= 5) 1.368, D, (n = 4.5) = 1.349 g ~m-~.Space group I2/c or Ic from systematic absences (non-standard settings of C2/c or Cc), 12/c by structure analysis; equivalent positions &(x, y, z; x, -y, 9 + z; 3 + x,8 + y, 4 + 2; 8 + x,a -y, 4.1 Unit cell dimensions were refined from 25[24] reflections. The crystal quality was tested and the scan width set to €;IGURE 1 The designations of the atoms of the bicyclic com-pound in the cyclophanc system. Letters A-c denote benzene rings.Hydrogen atom H(n) is attached to carbon C(n). The conformation is that of the uncomplexed molecule (I)showing alternative sites for O(28). Atoms subject to aniso- tropic refinement are shown as ellipsoids at the 30% confidence level by means of the program ORTEP lo (0.8 + 0.35 tan 0)O [(1.0 +-0.35 tan 0)OJ. A prescan speed of 2' rnin-l was used and weaker reflections collected for up to three times as long as strong ones; backgrounds were counted each side of the scan.Reference reflections (115) and (I, 1, 11) [(114) and (226)l were measured every 2 h during the course of data collection; in 5 days [3 weeks] no J.C.S. Perkin 11 change was found. For (I) each reflcction in the range 1 6 0 6 22" was scanaed twice; 3 043 unique reflections were measured of which 1775 had IFo/ 2 3aF and were considered ' observed '. [For (11)two quadrants, hkl and hkl, were measured, each reflection in the range 1.5 < 0 (22" being scanned once, after averaging 3 918 unique reflections were obtained of which 2 138 having IF,,[-> 2cr~ were considered ' observed ']. While all unique reflections were used in SHELX to determine the approxi- mate scale and E values for direct methods, only the ' observed ' were used for structure factor calculation and parameter refinement.Computer programs were the CAD4 processing and the SHELX suite for structure determination and refinement run on the ICL system 4 of Kothamsted Experimental Station, while for molecular geometry the X-RAY ARC programs for the IBM 1 130 were used. Scattering factors were calculated using the analytical approximation coefficients given in Table 2.2R of ref. 9 for Kt, C1-, C, H, and 0 (water molecules also being treated as 0). Slructure Determination of (I).-A multisolution direct methods program gave one set of signs for the 346 E values greater than 1.2 and all the non-hydrogen atoms appeared in the corresponding E map.The numbering adopted in both compounds is shown in Figure 1 which depicts the configuration of the molecule in (I). Refinement with isotropic vibration parameters gave R 0.14. An electron density difference map showed features attributable to hydrogen atoms in geometrically likely positions and also a peak, 3 eA-3, close to O(28) and out of the plane of ring c,the atoms of which appeared to be uncler- going very anisotropic vibration, the main displacement being normal to the plane of the ring. Experiments with CPK models involving rotation about the bonds C(3)-C(27) and C(18)-C(36) indicated that several conformations were possible, two of which resulted in approximately parallel displacement of atoms O(28) O(35) inclusive along the normal to ring c.Various possibilities were examined in successive least squares refinements ; the best approxim- ation to the electron density distribution was found by allowing anisotropic vibration for atoms C(27) and C(22)-C(36) inclusive and partial occupation of two sites for O(28) designated O(28) and O'(28) as shown in Figure 1. As these two sites correspond to different orientation of the bonds about C(27) there are two hydrogen atoms cor-responding to 0(28), H(27A) and H(27B), and two cor-responding to 0'(28), H(27C) and H(27D). The occupation number of O(28) was a parameter, those of O'(28) and the hydrogen atoms of C(27) being adjusted accordingly. Hydrogen atoms were fixed at 0.98 A from the correspond- ing carbon atom in geometrically calculated positions, their isotropic vibration parameters were linked in groups, i.c.on ring A, on ring 13, on ring c, on CH, groups [other than C(27)] while for H(27A-D) a fixed value 0.09 A2was used. Refinement as considered complete when the la-gest shift in a parameter was less than 0.04 of the corresponding standard deviation. R Was then 0.066, R' with unit weights was 0.062, and there was a uniform distribution of R' in IFo\ or sin el?,. In the final electron density difference map the largest peak was 0.6 ek3 and the deepest ' hole ' 0.3 ek3; every peak was within 0.8 A of at least one of the atoms so there was no evidence for any solvent molecule. In the full matrix refinement, as might be expected, the occupation number of O(28) was highly correlated with the isotropic vibration parameters of 0(28) and O'(28) ; the other correlation coefficients greater than 0.6 were for 0(36), U,,being correlated with V,, and Us*.Atomic co-ordinates and vibration parameters are in Table 1; those for hydrogen atoms have been deposited in Supplementary Publication No. SUP 22903 (37 pp.) * with the Tables of structure factors. Stmctwe Determination of (11).-Systematic absences corresponded to space groups I2/c or Ie (non-standard settings of C2/c and Cc). A three-dimensional Patterson synthesis revealed one set of peaks corresponding to an atom at 0.4,0,-0.1 and sufficient peaks in the Harker section at V = 0 to suggest the presence of a two-fold axis.As K+ and C1-have nearly the same scattering powers, a more complicated synthesis was expected corresponding to two independent heavy atoms and vectors between them. Direct methods yielded a solution with one most electron-dense atom; the E statistics corresponded to a centric distribution. This one atom was used to phase a Fourier synthesis despite a high R value, 0.54, and the electron density map clearly showed eight oxygen atoms of the bicyclic molecule round the heavy atom, now identified as the potassium ion. One cycle of isotropic refinement and a difference synthesis revealed the remaining atoms of the cationic complex, shown in Figure 2. Isotropic refinement yielded R 0.18, and a difference synthesis showing seven peaks at ca.3 eA-3 and many smaller ones in positions which corresponded to hydrogen atoms of the complex cation. Inclusion of the hydrogen atoms led to smooth refinement of the parameters of the cationic complex, but difference synthesis did not reveal any peak which could be assigned to the chloride ion; a number of peaks did appear, ca. 1 A apart and with heights ranging from 1.1 to 2.6 eA-,. It was clear that these represented sites partially occupied by FIGURE The complex cation in (11)showing the observed con-2 formation with the ellipsoids at the 30% confidence level for the potassium and the carbn atoms of ring B water molecules and by chloride ions; the problem then became one of refining the parameters of the atoms of the complex cation and obtaining the best representation of the electron density in the disordered sites, in the knowledge that these aspects are not independent, and that the number of parameters which could be handled by the SHELX programs is 319, quite as many as can be determined from 2 138 observations. For the complex cation possible * For details of Supplementary Publications see Notice to Authors No.7 in J.C.S.Pevkin 11, 1979, Index Issue. anisotropic vibration was bhecked. In one cycle the aniso-tropic vibration parameters of the oxygen atoms and the potassium ion were determined; the' former were nearly isotropic and assumed to be so subsequently. Next the carbon atoms of the benzene rings were allowed anisotropic vibration; only for ring B were they significantly different from those for isotropic vibration so final refinement allowed anisotropic parameters for K" and for ring B. The small TABLE1 (a) Atomic co-ordinates (fractional x lo*)for (I), the macro-bicyclic compound.Isotropic vibration parameters Ulso(A2 x loa). Here and throughout the paper the standard deviations in the least significant digits are in parcntheses Atom X Y 2 UiSO O(1) 6 016(4) 4 416(4) 4 344(2) C(2) 6 228(6) 6 299(7) 3 981(3) 63(2)(33) 3 986(6) 6 024(7) 4 113(3) 46(2)O(4) 3 286(4) 5 979(4) 3 744(2) C(6) 2 086(6) 6 016(8) 3 837(3) 61(2)C(6) 1324(6) 6 119(7) 3 259(3) 62(2)O(7) 1447(4) 4 847(6) 2 943(2) C(8) 890(6) 4 746(7) 2 378(3) 50(2)C(9) -60(6) 6 676(8) 2 141(3) 64(2)C(W -640(7) 5 366(9) 1657(3) 76(2)C(11) -121(7) 4 420(8) 1210(4) 73P)C(12) 842(6) 3 664(7) 1436(3) 60(2)315(2)C(13) 1319(6) 3 719(7) 2 027(3) 47M O(14) 2 213(4) 2 294(6) C(16) 2 617(6) 1762(7) 2 002(3) 66(2)C(16) 3 339(6) 836(7) 2 437(3) 53(2)O(17) 4 434(3) 1478(4) 2 631(2) C(18) 6 271(5) 666(7) 2 942(3) 48(2)C(19) 6 386(6) 1371(7) 3 088(3) 53(2)O(20) 6 260(3) 2 491(4) 3 495(2) C(21) 7 228(6) 3 206(6) 3 726(3) 38(2)C(22) 8 332(6) 2 976(7) 3 681(3) 50(2)C(23) 9 291(6) 3 741(7) 3 866(3) 61(2)W4) 9 143(6) 4 723(7) 4 271(3) 59(2)C(26) 8 049(6) 4 962(7) 4 427(3) 50(2) C(26) 7 089 6) 4 223(6) 4 164(3) 40(2)CP7) 3 68210) 3 604(6) 3 946(3) O(28) 2 864(7) 2 869(7) 4 248(3) 60(3)O'(28) 3 710(12) 2 926(13) 4 676(6) 44(5) C(29) 3 166(7) 1612(7) 4 525(3) (330) 2 607(7) 1 204(7) 5 OOl(3) c(31) 2 601(7) -134(8) 6 216(3) C(32) 3 181(7) -1 144(,8) 4 960(4) C(33) 3 769(7) -863(7) 4 490(3) C(34) 3 769(6) 472(6) 4 260(3) O(36) 4 274(6) 839(6) 3 783(2) C(36) 4 839(6) -167(7) 3 466(3) 65(2) @) Anisotropic vibration parameters (A2 x lo3) in the form expC-2~8 (U,,h%** + U2,R2b*2 + U,,Z2c*2 + 2UI2hka*b* + 2 U,,hla*c* + 2U,,klb*c*) Atom U(11) U(22) U(33) U(12) U(13) U(23) O(1) 63(3) 46(3) 50(3) ll(2) lO(2) 2(2) O(4) 44(3) 36(3) 95(4) 6(3) 17(2) 8(2) O(7) 66(3) 49(3) 62(3) 14(2) lO(2) -5(2)O(14) 63(3) 54(3) 66(3) 9(2) 2(2) -17(2) O(17) 40(2) 44(3) 60(3) -2(2) 6(2) -12(2) O(20) 37(2) 40(3) 69(3) 3(2) 9(2) -21(2) C(27) 70(6) 28(4) 72(5) -6(4) 18(4) 5(4)118(7) 23(4) 80(6) -6(4) 42(6) 2(4) 121(7) 42(5) 74(6) -7(4) 58(5) -6(5)g[tt{C(31) 111(7) 64(5) 62(5) -16(4) 27(5) 6(5)C(32) 114(7) 41(5) 74(6) -7(4) 21(5) 22(5) C(33) 86(6) 28(4) 66(6) l(4) 16(4) 1(4)81(5) 23(4) 62(4) -8(3) 18(4) -2(4) 29(3) 90(4) 14(3) 78(4) -1(3)gg\ 146(6) departure from isotropic vibration suggests that the cations are notdisordered and, in particular, that they truly have the space group symmetry I2/c.This space group was retained in treatment of the disordered atoms; co-ordinates 4 J.C.S. Perkin I1 could only be obtained reliably from difference maps, as shown by attempted refinement, so these were fixed. If all the peaks were treated as oxygen, with occupation numbers TABLE3 fixed a.t 0.5 and their isotropic vibration parameters allowed (a) Bond lengths (A) TABLE2 (1) (11) (1) (11)C( 23)-C( 24) 1.361(9) 1.38(2) C (2 1)-C(26) 1.404(8) 1.38(2)(a) Atomic co-ordinates (fraction x lo4) for the complex with C( 24)-C( 25) 1.3 7 8(8) 1.35(2) C( 23)-C(22) 1.398( 9) 1.38(2)potassium chloride.W represents a water molecule, A and B C( 25)-C( 26) 1.380(8) 1.38(2) C(22)-C(21) 1.378(8) 1.37(2)distinguish alternative sites; the last column is the site occupation C(26)-0 (1) 1.381(7) 1.36(1) C(21)-O(20) 1. n60( 7) 1.39(1)number. Isotropic vibration parameters Uiso(Azx lo3) 0(1)-C(2) 1.419(7) 1.42(1) 0(20)-C( 19) 1.440(7) 1.43(1) X Y z C (2)-C (3) 1.52 9 (8) 1.48(2) C(19)-C( 18) 1.500(8) 1.49( 1) C( 3)-O( 4) 1.415(7) 1.43(1) C( 18)-0 (17) 1.41 9 (7) 1.42( 1) 3 298(1) -675(1) 1318(2) O(4)-C( 5) 1.431(7) 1.43(1) 0(17)-C( 16) 1.41 7 (7) 1.42(1)2 934(4) -843(5) 2 034(5) C(5)-C(6) 1.480(8) 1.49(1) C(16)-C (15) 1.49 2 (9) 1.48(1)2 508(6) -226(7) 1902(7)2 565(5) 207 (7) 1 158(7) C( 6)-0( 7) 1.430(8) 1.47(1) C(15)-0 (14) 1.434( 7) 1.43(1) 0(7)-C (8) 1.360(7) 1.37(1) O(14)-C( 13) 1.372(7) 1.38( 1) 3 156(3) 524(4) 1276(4) C(8)-C (9) 1.390( 9) 1.38(2) C( 13)-C ( 12) 1.389(8) 1.41 (2) 3 288(5) 1047(7) 666(7) C(9)-€(10) 1.385(9) 1.38(2) C( 12)-C( 11) 1.41 6(9) 1.40(2)3 888(5) 1 403(7) 954(7) C( lO)-C( 1 1) 1.337( 10) 1.33(2) C( 13)-C( 8) 1.399(8) 1.38(1)4 332(3) 774(4) 978(4) C (3)-C (27) 1.530(8) 1.53(1) C(18)-C(36) 1.522(8) 1.51(1)4 925(5) 954(7) 1240(6) C( 27)-0 (28) 1.39 3 (9) 1.45(1) C(36)-O(35) 1.416(7) 1.43(1)5 141(6) 1689(7) 1 470(7) 0(2 8)-C (29) 1.465 (9) 1.38(1) O(35)-C( 34) 1.358( 7) 1.39(I)5 747(6) 1796(8) 1718(8) C (29)-C (30) 1.3 72 (9) 1.41(1) C(34)-C(33) 1.372(9) 1.39(1)6 133(6) 1206(7) 1 744(7) C(30)-C(31) 1.369(10) 1.38(2) C(33)-C(32) 1.369(9) 1.40(1)5 937(6) 451(7) 1520(7) C(31)-C(32) 1.353(10) 1.34(1) C(29)-C(34) 1.392(9) 1.35(1)5 315(5) 333(7) 1267(6) C(27)-O’(28) 1.533( 14) 5 066(3) -385(4) 1035(4) 0’(28)-C(29) 1.487( 14) 5 458(5) -1045(6) 1074(7)5 082(5) -1 736(6) 825(7)4 703(3) -1 871(4) 1410(4) (b) Bond angles (”).Estimated standard deviations arc iii 4 358(5) -2 567(7) 1327(6) parentheses except for bond angles of compound (TI)which range 4 OFiR(5) -2 645(7) 2 052(7) from 0.8 to 1.4” 3 C74(3) -1 992(4) 2 088(4) Bond angle abc v3 318(6) -1 978(8) 2 693(7) a b c d (1) (11)3 349(7) -2 517(b) 3 301(8) C( 2 1)-C( 26)-0 (1)-C (2) 120.4(5) 1172 971(9) -2 424(11) 3 864(9) C(25)-C(26)-0 (1)-C (2) 119.3(5) 1232 578(8) -1 804(13) 3 823(10) C(26)-0 (1)-C( 2)-C (3) 11 5.1(5) 1202 553(6) -1 277(9) 3 221(8) O(l)<(2)-C( 3)-0 (4) 108.9(5) 1112 923(6) -1 359(8) 2 647(7) 0(1)-C( 2)-C( 3)-C( 27) 2 389(5) -230( 7) 355(7) C( 2)-C( 3)-0 (4)-C(5) 104.1(5) 1072 852(3) -800(4) 295(4) C( 27)-C(3)--0(4)-c( 5) 112.0(5) 1142 732(5) -1 355(6) -307( 7) C( 2)-C( 3)-C( 27)--O (28) 10 7.6 (5) 1172 236(5) -1 297(7) -935( 7) C( 2)-C( 3)-C( 27)-0’( 28)2 158(6) -1 898(7) -1 487(7) 0(4)-C( 3)-C (2 7)-0 (28)2 537(5) -2 504(7) -1 458(7) 0(4)-C (3)-C (27)-0’ (28)3 034(5) -2 563(7) -837(6) C(3)-0 (4)-C( 5)-C( 6) 114.2(5) 1163 112(5) -1 969(6) -267(6) 0(4)-C( 5)-C (6)-0 (7) 109.4(5) 1083 586(3) -1 958(4) 381(4) C( 5)-C( 6)-0 (7)-C( 8) 107.6( 6) 1073 955(5) -2 636(7) 517(7) c(91-c (8)-0 (7W (6) 124.4 (6) 125-1 122 280 6 286 C(6)-0 (7)-C( 8)-C( 13) 11845) 118-1 054 61 7 205 0(7)-C( 8)-C( 13)-O( 14) 115.7(6) 115W(1)A 763 873 5 894 C(8)-C( 13)-0(14)-C(15) 114.7(5) 117W(1)B 657 692 6 538 C( 12)-C( 13)-O (14)-C( 15) 125.0 (6) 123W(2).4 473 1370 3 623 C(13)-0(14)-C(15)-C(16) 117.8(5) 118W(2)B 472 1346 2 895 O(14)-C( 15)-C( 16)-0 ( 17) 108.6(5) 107W(3)A 461 1389 4 861 C( 15)-C( 16)-0 (17)-C( 18) 109.9(5) 1onW(3)B -16 1391 4318 C( 16)-0 (17)-C( 18)-C (19) 113.7(5) 117 -907 543 4 586 C( 16)-O( 17)-C( 18)-C (36) -732 396 5 350 0(17)-C( 18)-C( 19)-O( 20) 106.8(5) 108W(5)A -1 092 956 3 100 C(36)-C( 18)-C( 19)-0(20) 11 5.4( 6) 116W(5)R -978 915 3 881 0(17)-C( 18)-C( 36)-0 (35) 113.4(5) 113W(6) 126 729 7 199 0(35)-C (36)-C( 18)-C (19) 108.6(5) 1on (b) Anisotropic vibration parameters (A2x loa) in the form C( 18)-C( 19)-0 (20)-C( 2 1) 111.1(5) 109 e~p[-2r~(U,,h~a*~+ U,,k2b*2 + U,3Z2c*2+ 2UI2hka*b* + C( 22)-C( 2 1)--0 (20)-c (19) 124.9(6) 124 2 U,,hZa*c* + 2U2,KZb*c*)] C( 19)-O(20)-C( 2 1)-C( 26) 117.5(4) 118 Atom U(11) U(22) U(33) U(12) U(13) U(23) 0(20)-C( 21)-C( 26)-O( 1) 116.5(5) 115 C (3)-C( 2 7)-0 (28)-C (29) 1 16.1 (6) 108 K PO(2) 61(2) 65(2) l(1) 8(1) 7(1) C (3)-C( 27)-0’ (28)-C (2 9) 97.9( 7) C(21) 64(9) 73(9) 42(8) -24(7) lO(7) 304) C (30)-C (29)-0 (2 8)-C (2 7) 114.7(7) 122C(22) 90(11) 96(11) 56(9) -51(9) -2(9) 18(9) C (2 7)-0 (2 8)-C (29)-C (34) 117.0(6) 118C(23) 123(16) 130(16) 43(9) -81(10) 14(11) l(13) C(30)-0 (29)-O’( 28)-C(27) 112.0(8)C(24) 91(14) 168(19) 60(11) -71(13) 42(10) -39(13) C (2 7)-0’ (2 8)-C (2 9) -C (34) 107.6( 9) C(25) 68(10) 120(12) 39(7) -37(8) 23(7) -10(9) 0(28)-C (29)-C (3 4)-0 (35) 123.4(6) 117 C(26) 68(10) 72(10) 45(8) -45(7) O(7) 303) 0’(2 8)-C (29)-C (34)-0 (35) 117.0(8) C (29)-C (34)-0 (3 5)-C (36) 117.5(6) 115to vary, it became clear that the two peaks of highest C(33)-C( 34)-O( 35)-C36 124.7(6) 123 electron density corresponded to fractional chloride ions C (34)-0 (35)-C (3 6)-C (18) 12 1.3 (5) 118 Cl(A) and Cl(B). In the next cycle of refinement, the appropriate scattering factors were used for these two L-J W FIGURE Stereopairs of (a) the uncomplexed 3 167 33 3 27 Ih) -17G 168 18 4FIGURE Torsion angles in the bicyclic coinpounds (a)in (I)and (b) in the complex cation in (11).For clarity the values shown have been rounded to the nearest integer; estimated standard deviations range from 0.4" at 180" to 1.0"at 0" in (a) and similarlv from 0.9" to 2.5" in (b). In (a) angles involving O(928)are above or to the left of those involving O'(Z8). It is not possible to show all those involving the bridgehead carbon atoms C(3) and Cjl8); those depicted are in the 14-crown-4 ring; additional angles are O(l)-C(2)-C(3)-0(4) 178" (a)-61" (b); 0(4)-C(3)-C(27)-0(28) -992" (a) 53" (b); 0(4)-C(3)-C(27)-O'(28) -137" (a); 0(17)-C(l8)-C(36)-0(35) -444" (a) -556" (b); and 0(17)-C(l8)-C(I9)-0(20) 65" (a) 61" (b) -1 nmlecule (I) and (b) the complex cation in (I1) atoms. The Uisovalues for the oxygen atonis of the water molecules were very different and a better model was obtained by assuming the same isotropic vibration para- meter for all and allowing the occupation numbers to vary.For Cl(A) and Cl(B) occupation numbers were constrained to add up to unity, for the water molecules W(l)-\V(5) inclusive those for (Aj itnd (B) were allowed to vary intle- pendently, and that of W(6), which is close to the two-fold axis, was fixed at 0.5. The co-ordinates of W(6) refined to a position off the two-fold axis. The implications of the disorder and the space group ambiguity are discussed later.Table 2 gives the final atomic parameters corresponding to an R value of 0.104 (a smaller value can be obtained with more parameters for the disordered atoms but the physical significance of these is questionable). The disordered columns were fixed and a final cycle of refinement of the cation gave the maximum shift in a parameter 0.06 of the corresponding standard deviation; correlation coefficients >0.5 were found for several parameters of C(23) and between its co-ordinates and those of C(24). The wcighted R' value was 0.117, w being 3.47/(0~(~>counting4-0.000 61F12). The structure factor Tables arid the para- meters for hydrogen atoms are in SUP 22903.RESULTS AND DISCUSSION The compound was synthesised by bridging a tlibeiizo-14-crown-4 dio1,l corresponding to the benzene rings 13 and c with 0(4) and O(17) as the two hy-droxy oxygen atoms. In the systematic numbering, the bridge which includes a benzene ring consists of atoms 5-16. Figure 3 shows stereopairs of the molecule in (I)and the cation in (11). There is no discernible symmetry in the free molecule. In the complex a non-crystallographic plane of sjm-metry passes through the potassium ion and the mid- points of two bonds in each benzene ring, C(8)-C(13), C(10)-C (11), C(21)-C (26), C(23)-C (24), C(29)-C (34), and C(31)-C(32). In Table 3 the bond lengths and bond angles have been arranged to display this and to facilitate comparison between compounds (I)and (IT).Figure 4 shows the torsion angles in (I)and the cation in (11). In (I) the average aromatic C-0 distance [excluding 0(28)] is 1.366 A, average aliphatic C-0 [excluding O(ZS)]is 1.424 A, and the aliphatic C-C bond is 1.509A, the usual short value for carbon atoms separating two oxygen atoms. In (11)the corresponding averages are, respectively, 1.38, 1.43, and 1.50 A with deviations indicating that the values for the e.s.d. in Table 3 are realistic. The only possible significant difference, excluding O(ZS), between the bond lengths in (I)and (11) is that C(2)-C(3) is 0.053 A, 3.2 CS,longer in (I). In the free molecule the distance between the oxygen atoms on the same benzene rings 0(1)* O(20) and O(28) O(35) are 2.71 and 2.84 A respectively, both longer than in the complex while the Q(7) O(14) ‘ bite ’ is the same, 2.57 A.The change in conformation affects one half of the molecule, as shown by tlic torsion angles in Figure 4. About six bonds there are changes in TABLE 4 Mean planes through various groups of atoms in A. Equations of the planes are in the form Zx’ + nzy’ 4-?zz’:= tl$-0 where x’, y’ and z’ are co-ordinates with J.C.S. Perkin I1 TABLE4 (continued) I(Dii) (C) C(29) -4(8) -1(11) (U) O(1) 114(4) -6(8)C(30) O(8) 7(12) O(28) -497(7) 6(7) C(31) -7(8) -9(12) O(35) 285(5) -6(7) C(32) -1(8) 3112) O(20) -253(4) 6(7)C(33) 6(7) 4(11) O’(28) 351(13) k(34) -4(7) -5(11) K 1 935(2) 557(2)O(28) -333(7) -I6(7) O(35) -45(6) -1l(7)C(27) 156(7) -285(12) C(36) -124(7) -l92(11)O’(28) 804(13) (E) 0(7) 13(7) (F) O(1) -1(8) (1) O(1) -t 123 O(28) -13(7) O(7) 1(7) :[;I -fiXO(14) -13(7) O(20) 1(7) O(35) 13(7) O(l4) -1(7) O(14) 108 I< I 104(2) K -387(2) O(17) -2227 O(4) -368(7) O(20) 113 O(17) -3.31(7) Angles (”) between normals to planes.Observed values are in thc lower left hand corner; ideal values for a trigonal prism (Figure 5) are in the upper right hand corner for compound I1 in italics. 1 (A) (W (C) (IX) (13) 51.0 (C) 61.7 69.4 (IX) 100.4 29.1 45.1 (1Xi) 110.2 19.1 50.4 13.5irrcspect to orthogonal axes a’ and b‘ parallel to thc (V (F) (GI (W30 30 crystallographic n and h axes and G’ perpendicular to (A) (R) (C) (1360 60 9001)both 90 1 1.8 d (13) 74.6 60 SO 90 30 90 90 (C) 36.5 68.9 30 30 90 90 90 I<enzene ring atoms C(8)-C(13) 1 0.68 1 0.676 --0.281 -1.721 I[ -0.271 -0.189 0.944 1.293 I3cnzene ring atonis C(21) -C(2G) I 0.063 -0.698 0.714 -4.310 11 0.615 0.548 0.567 -4.815 13enzene ring atonis C(29)-C(34) I 0.751 0.205 0.637 -8.347 IT 0.659 0.499 -0.563 -.3.251 (i), 0(1), 0(20), O(36) I 0.533 -0.530 0.660 -7.184 (ii), 0(1),0(20},0(38), 0‘(28), O(36) 0.33 3 -0.520 0.786 -7.346 ()x\;gen atoms in the co-ordination polyliedron in I1 o(l),0(20), 0(28),o(35) 0.763 0.630 0.091 -4.015 0(7),0(28), 0(14),O(R5) -0.227 -0.129 0.965 0.782 0(1),0(7), 0(20), O(14) 0.261 0.260 0.929 -4.330 0(1), 0(7), O(28) -0.640 0.767 -0.046 5.148 0(14), 0(20),O(35) -0.639 0.767 -0.046 7.717 0(1), 0(4),0(7), O(14) ()(IT), (O(20) 0.258 0.264 0.930 --4.180 I)irc-ction cosinc.s (a) O(4) * --O(17) 0.643 --0.765 0.041 (1)) O(1) * * O(20) 0.643 -0.7155 0.035 (c) O(7) * O(14) O.ti37 -0.770 0.036 ((I) O(2X) * * .o(m) 0.034 -0.771 0.056 Ikviationq (lo3A) of atoms from the planes; those in italics \yere not included in calculation of the equations T 11 8(7) -3(11) (13) C(21) O(6) O(13)7(7) I(12) C(22) 4(7) 3(14) -13(8) l(l3) -1(7) -4(19) 3(8) -1(12) -6(?) 2(14)C(12) 12(7) -l(16) ll(6) l(14)C(13) --17(6) :{(lo) -8(6) 2(13)K I 262(2) I018(2)27(4) -lO(7) 89(4) 28(8)-7.5(4) 9(7) 3!1(4) 18(7)482( 7) 18(1.2) 1 236(7) -85(12)240(7) 48(12) l49(7) -89(12) (1)) (IS) 4.4 70.3 40.8 99.7 I20 90 00 (17) 40.8 33.9 102.8 116.8 143.6 90 no (G) 89.1 90.0 89.2 89.8 90.1 89.4 180 (H) 90.9 90.1 90.8 90.1 89.9 89.5 179.9 (I) 40.8 33.9 102.8 116.7 143.6 0.29 89.7 8!).7 Angles bctween the normal to plane (C) and the 0 * * * 0 vectors (a)0.0, (b) 0.9, (c) 0.7, (d) 1.4”.kind, trans or gauche; these are C(26)-0(1), C(2)-C(3), C(3)-C(27), C(S7)-0(28), O(ZS)-C(29), and 0(4)-C(5). These alter the intramolecular oxygen atom separations ; O(4) is 3.58 A from 0(1), 2.81 from O(7), and 5.25 from O(28). while O(17) remains more nearly equidistant from 0(14), 0(20), and O(35) at 2.91, 2.83, and 2.73 A, respectively. Although some torsion angles in (I) differ from the ideal values 60 or 180” there is no evidence for intra- inolecular C-H 0 hydrogen bonding [excluding the disordered H(27) or 0(28)].The shcrtest H 0 distance is O(14) H(16B) 2.48 A. Planes of the benzene rings with the deviations of the catechol oxygen atoms and of the neighbouring carbon atoms are given in Table 4. The oxygen and attached carbon atoms are significantly out of these planes in (I) but, except for C(27) and C(36),not in the complex (11). Plane (D)comprises the four oxygen atoms of the parent 14-crown-4: because of the disorder in (I), we have calculated the plane (Di) for three oxygen atoms and also (DiJ including both positions for O(28). In both (I) and (11) the benzene rings n and c are not equally inclined to this plane.The main change from the uncomplexed to the com- plexed form is that in the former five oxygen atoms, 104.0 29.4 30.5 120 120 90 90 O(4), 0(7), 0(14), O(l7), and O(20) are cn a fairly open face while, in the complexed form, 0(1)is, as shown in plane (I), also in this more open face. An open face is also found in other uncomplexed molecules in this series as described in the following paper l1which gives 4 17 ~:IGURE6 An end-capped trigonal prism : numbering of the corners corresponds to the oxygen atonis in (11), letters on loops to the benzene rings the comparison between (I) and a molecule having CH, groups instead of a benzene ring at C(8) and C(13). Co-ordination of thc: Potassiunz 10n.-~\s shown in Figure 2, co-ordination is solely by eight oxygen atoms of the ligand; these are arranged approximately in an end-capped trigonal prism shown in Figure 5 with the K+, 0, and benzene rings differs from that of DShsym-metry in that the line joining 0(4)-K-0(17) does not pass through the mid-point of the triangular faces.In Table 4 the observed angles between the plane normals are contrasted with ideal values from a trigonal prism with D3h symmetry as in Figure 5. These deviations are all such that K, 0(4), and O(17) lie sufficiently close to plane (F),and benzene rings A and B are at such angles to it as to make that part of the molecule, atoms (1)-(26) inclusive, comparable with complexes of dibenzo-18-cr0wn-6,~~and the tetramethyl substituted derivatives l3 noticeably in the torsion angles (Figure 4),trans about C-0, gauche about CH2-CH,.This comparison is also shown in plane (I), through the six oxygen atoms and suggests that the caesium ion in the 1 :2 complex could be sandwiched between two six-oxygen faces. This finding also reinforces a point made by Coxon and Stoddart,14 who synthesised molecules RC(CH,OCH,- CH,OCH,CH,OCH,),CR which proved disappointing as ligands, i.e. the need to base a molecule on units having only two carbon atoms between the oxygen atoms as Pedersen l5 found in his original crown ethers. How-ever, the six oxygen atoms differ from coplanarity by significant amounts, and we regard the end-capped trigonal prism as a useful description. In their molecular orbital treatment of eight co-TABLE5 Co-ordination of the potassium ion; the ordering of the atoms demonstrates the pseudosymmetry of Figure 5 K-O(a) distance O(a)-K-O(b) angles (") (standard deviation 0.2") A O(7)2.690(8) 62.4 2.728(8) 120.9 2.740(8)2.741 (7) 2.740 (7) 2.735(8) 2.709(8) 2.684( 7) Bond angles K-O-C(") PI 11 6.0( 7) 12 1.3 (8)107.4( 6) 106.8 (6) 1 1 5.1 (6) I1 8.6 (6) 118.6 (6) 1 2 3.9 (6) corners numbered to correspond to the oxygen atoms in (11). The triangular faces are formed by O(l), 0(7), O(28) and 0(20), 0(14), O(35). These, as shown in Table 4, are parallel to one another and normal to the planes (D)-(F) of the rectangular faces while the atoms O(4) and O(17) cap the ends.The twist angle between faces (G) and (H) is 0.5" (cf.0" for a trigonal prism and 60" for a trigonal antiprism). Bond lengths and angles involving potassium are in Table 5 which shows that the I<-0 distances to the oxy-gen atoms on the aromatic rings average 2.733 A, while those to the capping atoms O(4) and O(17) are signifi- cantly shorter, 2.687 A. The pairs of oxygen atoms on the benzene rings form the prism edges; the system 62.6 63.8 0(28) 89.5 O(35)118.6 163.7 O(14)118.7 117.6(20)56.6 O(17)1 78.2 118.0 103.4 133.0 56.3 163.6 118.0 56.1 131.9 89.8 118.5 103.4 62.6 62.5 120'9 61.8 61.4 [OI [CI(20) 1 1 7.2 (6) (19) 12 1.6 (7) (20) (21) (17) 107.2 (6) (17) (' 8, 107.2 (6) ('(14) (15) 1 16.1 (6) (14) (13) 11 7.6 (6) (3 5) (36, 11 7.5( 6) (35) (34) 1 2 4.4 (6) ordination, Burdett et aZ.16 showed that, while this geometry is favoured on electronic grounds, it is steric- ally very unfavourable.The minimum energy geo-metry is found theoretically if the angles subtended at the centre between the capping atoms and the atoms of a triangular face are 58"; this corresponds to the set of angles O(4) to 0(1),0(7), O(28) or O(17) to 0(20), 0(14), O(35) which, as Table 5 shows, range from 61.1 to 62.6". The theory also predicts that the end-capping position should be occupied by the more electronegative (or better CT electron acceptor) ligand; as an oxygen atom between two aliphatic carbon atoms is more electro-negative than one attached to a benzene ring, the pre- diction is borne out in this example.J.C.S. Perkin II The complex is one example of toleration by do tion in the metal-nitrogen relative to the metal-oxygen cations of the higher energy possibilities for eight co- distance. ordination in regular discrete polyhedra. Other exam- Changes in conformation between the complexedples are the hexagonal bipyramid in some complexes of (cryptate) and uncomplexed cryptand 21 differ from those for (I); there are changes about the three central TABLE6 CH,-CH, bonds [the equivalents in (I) being fixed as Selected interniolecular distances in (I) including all benzene rings] and about the C-0 bonds. Angles 0 H and C H distances less than 3.0 8, and involving the bridgehead nitrogen atoms are unchanged.H H distances less than 2.6 lntermoleculaar Contacts.-In Tables 6 and 7 ' selected ' as.. b b-.*a 3.20 I I1 TABLE7 3.00 I1 2.73 I I I1 Selected intercationic contacts in (11) including all 0 H 3.00 I I1 and C H distances (3.0 8, and H H distances 2.81 VII VIII 2.59 I11 I11 3.56 I11 I11 a,. . .b b0s.a 2.832.63 IV IV 3.57 IV IV 2.95 IV IV 2.67 IV 1v 3.49 2.78 V VI 3.483.48 V VI 2.99 V VI 2.65 I 2.78 V VI 2.89 3.09 V VI 3.282.95 V VI 3.10 3.12 VII VIZI 3.07 2.89 VII VIII 3.20 2.90 VJ I VIII 3.19 I 11 3.31 I 11 2.583.03 I 11 2.96 2.31 111 IIJ 3.06 1 3.16 I11 IT1 3.25 11 1113.11 111 111 2.87 3.20 12.05 IT1 I11 2.98 I11 111 2.85 2.97 IX IX 2.81 J 2.60 IX IX 2.79 I IT 3.25 3.06 I I1 3.25 2.96 I I1 3.64 3.06 T I1 3.62 2.93 'I I1 3.60 2.52 I TI 3.28 2.87 X XI 2.45 111 I11 3.622.97 VIII VII 2.8 1 VIII VII 3.63 2.88 I I1 3.17 3.07 Roman numerals give the position of atoms related to those of 3.17 2.92the crystal chemical unit, x,y, z in Table 1 2.57 IV IV 1 1--,4ty,d-z VI x,y -l,z 2.89 1v JV I1 1 -x, -f! -t y, -;--z VII -x, -4 + y, 9 -z 2.96 IX V I11 1 -X, 1 -y, i -z VITI -x, + y, 4-z 2.78 IX V TV 1 -X, -JJ, 1 -z IX 2--x,l-y,1-2 2.99 VI XIV v x,y+l,z x x-l,y,z 2.65 VI XIV Tn the designations of hydrogen atoms A and B distinguish Roman numeral superscripts relate the atomic positions to those those attached to the same carbon atom.of the crystal chemical unit in Table 2, at x,y, z I 1 -x, -y, --z VIH 8 + x, 3-+ y, -4 + z18-crown-6 derivatives (e.g. ref. 121, and the cube in I1 1 -x,y, -$ -2 IX 4 -x, -9 + y, --z complexes of n0nactin.l' The cube is a particular rrI i-~,-$--y,i--z x ~+X,--~+y,-~+z XI ++x,-+-y,zcase of an end-capped trigonal antiprism. The sodium IV ;-x,-j-y,-a-z v -x, -$ + y, -2 XI1 1 -x, -1 --y, -zcomplex l8 of the [222] cryptand, N(CH,CH,0CH2 VI x, -y, -4 +-z XI11 x, -1 -y, -4 + z CH,OCH,CH,),N is close to the general case having a VII 4 + x, 9 -y.l z XIV x, -y, i! + -z N system with the twist angle In the designations of hydrogen atoms A and B distinguishlinear N Na.those attached to the same carbon atom. between two triangles of oxygen atoms of 45.8" while in complexes of the larger cations potassium,l9 rubidium, intermolecular, or interrationic, distances are given ; all and caesium,20 the angle is 22.5, 14.4, and 15.3", respec- those less than the quoted limits are included. Those tively, nearer that for the end-capped trigonal prism. outside the limits have been selected, e.g. both a carbon This change in twist angle is accomDanied bv a diminu- atom and its attached hvdrogen atom, to make the end- 6FIGURE The structure of (I) in projection along the b axis. The Roman nnmeral superscripts refer to the equivalent positions defined in Table 6; those not displaycd here are IV, hcneath TIT; V nntl VI arc rcspectivcly almvc and below the crystal chem- ical unit; I1 is beneath 1, VITT is above VII FIGURE The cationic columns in (11)shown in projection down the h axis for the cations having the potassium between y = -*7 and ++.Roman numeral superscripts are defined in Table 7; those not shown here are IX one cell below V, X one cell below VIII, XI below VII, XI1 beiow I, and XI11 below VI on or side-on nature of the contact clear, For each benzene ring the possible contacts to be considered are (a) parallel stacking with another ring at ca. 3.5 A, or (b) ' meshing ' from hydrogen of another ring or from a CH, group characterised by the hydrogen being equi- distant from several ring carbon atoms and the dcnx C-H approximately normal to the ring.Both stacking or meshing contacts can appear on either side of a ring. An aromatic hydrogen atom may be meshed into a ring J.C.S. Perkin I1 other contacts. The second face of ring c is in contact with H(5B) in relation VI and H(10) in relation VII. Two of its hydrogen atoms contact oxygen atoms, see above. For ring A contacts from one side are from H(22) and H(23) of ring H-[; on the other H(6B)V11. Its hydrogen atoms H(10) and H(12) mesh into rings cV1l1and BII. Ring B receives a mesh contact from H(121) and on the same side contacts from H(16A) and H(15A) in relation FIGURE The structure of the cationic columns of I1 in a projection down the c axis showing the eight potassium ions having -18 < y < 0 so that only two cations overlap each of the projected points at 0, 4; 3, 0; 1, &, and 4,1.At each of these points there is overlap from a further two cations in the neighbouring unit cells. The spaces available for columns of water molecules and anions are visible at O,O,z and Q,Q,z. The Roman numeral designations are defined in Table 7 or in contact with an oxygen atom. For both com-pounds the packing will be described in these terms. Figure 6 shows the packing of (I). There are inter- molecular C-H * * * 0 contacts] with angles at hydrogen of ca. 160"; these are H(3) O(lrlI), H(32) O(1IV) [so that 0(1)is in two contacts about centres of sym- metry separated by one translation along the b axis], and H(33) O(4V') in the molecule in the next cell along b; the lengths exceed the sum of the van der Waals' radii.As shown in Table 4, the normals to the planes of the three benzene rings A-c are at ca. 60". Stacking is not important in this structure; the only such contact is from ring c to the one related to it by a centre of sym- metry at $,O,$ (relation IV) and this gives rise to con- tacts from C(34) to C(32) and C(33) of 3.8 A; although not representing a strong attraction it sterically prevents I, there are no significant contacts on the other side; from H(30) of ring clll there is a relatively close 2.31 A contact to H(25) edge on and a similar one H(24) . , . H(24)l" across the centre of symmetry at l,$,J.The structure of (11)consists of complex cations which are arranged as shown in Figures 7 and 8 to form chan- nels, along the crystallographic ' c axis, in which the water molecules and chloride ions occupy disordered sites. There is a superficial resemblance to an anion exchange resin but the cation columns are not polymers, consisting of discrete entities held, presumably, by van der Waals' forces; there is no evidence for efficient packing or strong inter-' molecular ' forces, as shown by the distances of various contacts given in Table 7. These have been arranged for ease of comparison with the packing diagrams with categories of types of contact. From the benzene ring A, nearest contacts are across a centre of symmetry at $,O,O (relation I) to the hydrogen atoms of the CH, groups, (15) and (16); on the other side are the contacts to the hydrogen atom (6B) of the molecule across the two-fold axis, (relation 11),and H(11) fits into one side of ring cl.The nearest to the stacking of aromatic rings is from ring B to the one related by a centre of symmetry at $,-&,* (111),on the other side of the ring in a contact from H(15A) in relation IT, and H(24) meshes into one side of ring c in relation 111. Ring c is contacted on one side by H(11I) on the other by H(24111); the centrosymmetrical relation at &,--k,-k (relation IVj gives an abutment at H(32). Comparison of Tables 6 and 7 shows that the minimum contacts of a given kind are longer between the cations of (11)than between the neutral molecules of (I).The only neighbours within 4 A of the potassium ion are two hydrogen atoms H(12) and H(15A) at 3.85and 3.51 A; both are in the complex cation in relation 11. Columm of Disordered Water Molecules and Chloride Ions.-In (11)the scattering attributable to one chloride ion and 4-5 water molecules per asymmetric unit cannot be precisely defined; this results in a high R factor and relatively large standard deviations evefi in the co-ordinates of the atons of the cation. The best representation of the electron density we could obtain is shown by the parameters of C1 and of water molecules W(l)-W(5), each of which may occupy one of two mutually exclusive sites designated A and B, and of W(6) at 0.6 A from a two-fold axis with occupation number 0.5.The occupation numbers were parameters ; the sum of those of Cl(A) and Cl(B) was constrained to 1; there was no constraint for W(l)-W(5) slid the refined values for A plus B are close to unity. A more detailed description includes a diagram in SUP 22903 together with a Table showing the distances of water molecules and chloride ions to the cations; none is less than the sum of the van der Waals' radii. There are more than sufficient potential hydrogen bonded contacts within the columns to accommodate all the hydrogen atoms. While the presence of a large amount of water is inconvenient from the point of view of a crystal structure analysis, it may be an indication that the structure found resembles that in solution.A similar channel of dis- ordered water molecules and chloride ions along a two-fold axis was found in a basic chromium acetate com-pound 22 [OCr,(CH,COO),-,3H20] +C1-,6H20. Chang If and Jeffrey attributed the disorder to the channel being surrounded by hydrophobic groups so that tetrahedral contacts could not be formed. Other crystals confaiiijxig complexed alkali metal cations with ' organic ' extwi*xs and networks of hydrogen bonded water molecules and anions have been described. One sodium ion between two molecules of 12-crown-4 (lJ4,7,10-tetraoxacyclo-dodecane) forms tlie cation in NaCl( 12-crown-4),,5H20 23 and in NaOH( 12-~rown-4),,8H,O.~~ The cations form layers between which are layers of ordered networks of water and anions.We are grateful to Dr. D. G. Parsons for the crystals, the Royal Society for some equipment, and tlie Computer Department, Rothamsted Experimental Station for facili-ties. REFERENCES D. G. Parsons, J.C.S. Perkin I, 1978, 451. J. M. Lehn and J. I-'. Sauvage, J. Amev. Chem. SOC.,1975, 97, 6700. D.G. Parsons, 1979, personal communication. 4 I. R. Manson, L). G. Parsons, and M. €3. Truter, J.C.S. Chem. Comtn., 1979, 486. 5 H. K. Prensdorff, J. Amer. Chem. SOC.,1971, 93, 600. CAD4, processor program, M. B. Hursthouse, Queen htary College, London, England. 7 G. M. Sheldrick, SHELX 76, Program system for crystalstructure determinaticm, Universrty of Cambridge. 8 X-Ray ARC, Library of programs for the IBM 1130 com-puter. World list of crystallographic computer programs, ./.App1. Cryst., 1973, 6, 309. 9 ' International Tables for X-Kay Crystallography,' Iiyiwcli Press, Birmingham, 1974, vol. 4, p. 90. 10 OKTEP Report No. OKNL-3794, C. I<,Johnson, Oak liidge National Laboratory, Oak Ridge, Tennessee, 1965. 11 J. D. Owen, J.C.S. Pevkan IT, following paper. l2 M. A. Bush and M. K.Truter, J. Chem. SOC.(B),1971, 1440. 13 P.R. Mallinson, J.C.S. Perkzn 11, 1975, 261. l4 A. C. Coxon and J. F. Stoddart, J C.S. Perkin I, 1977, 767. 15 C. J. Pedersen, J. Amer. Chem. SOG.,1970, 92, 391. l6 J. K. Burdett, €3. Hoffmann, and K. C. Fay, lnovg. Chcm., 1978, 17,2553. 17 M.Dobler, J. 11. Dunitz, and I3. T. Kilbourn, HeEv. Chiin. Acta, 1969, 52, 2573. l8 D. Moras and R. Wciss, Acta Cryst., 1973, B29, 396. l9 D.Moras, B.Metz, and K. Weiss, Acta Cryst., 1973, B29, 3%. 2o D.Moras, H. Metz, and I<. Wciss, i3ctn Cifyst ., 1973, B29 388. €3. Metz, D. Moras, and R. Weiss, J.C.S. Perkin I I, 1976, 423. 22 S. C. Chang and G. A. Jeffrey, Acta Cryst., 1970, B26, 673. 23 F.P.van Rcinoortere and F. P. Boer, Inovg. Cheni., 1974, 13, 2071. 24 F. 1'. Boer, h4. A. Neuman, 17. P. van Remoortere, and E. C. Steiner, Inovg. /;hem., 1974, 13, 2826.
ISSN:1472-779X
DOI:10.1039/P29810000001
出版商:RSC
年代:1981
数据来源: RSC
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