摘要:

NOTICE TO AUTHORSPublication of X-Ray Crystallographic Work in the Journal of theChemical SocietyIn September 1982 a working party was set up by the Society’sJournals Committee to consider updating the Society’sapproach to the publication of crystallographic structuredeterminations. This working party has received and evaluatedcomments from over thirty chemists and crystallographersincluding members of the Society’s Chemical CrystallographyGroup, and has produced the following set of guidelines,which are framed as a direct replacement for section 5 ofInstructions for Authors (see Perkin Transactions, 1983, Issue1 ; Dalton Transactions, 1983, Issue 3). These guidelines wereapproved by Journals Committee in June 1983, and shouldbe followed as from 1st January 1984 by all authors submittingcrystallographic results for publication.5.0 Publication of X-Ray CrystallographicCrystallographic work will be assessed mainly for its chemicalinterest.Thus crystallographic work carried out as part of awider chemical study should not normally be submitted forpublication separately from the results of that study. However,papers reporting only the results of crystal structure determin-ations may be accepted for publication provided that theseresults are considered to possess specifically chemicalsignificance.The description of a crystallographic structure determin-ation should be as brief as possible, consistent with thefollowing guidelines, and should be included at the end of apaper (or at the end of the Experimental section, if thisprecedes the Discussion).If the procedures for data collectionand structure analysis were routine, their description shouldbe particularly concise.Work5.1 Title and SummaryThe title of a paper reporting a crystallographic structuredetermination should normally contain the words ‘ CrystalStructure o f . . .’The summary need not contain cell dimensions and othercrystal data, but should make clear that a crystal structureanalysis has been performed.5.2 Presentation of Crystal DataThe following sequence should be employed (although notall items will be required in all cases): (1) chemical formulaand formula weight (M); (2) crystal system; (3) unit celldimensions (8, or pm, degrees) and volume, with estimatedstandard deviations, method of determination, and tempera-ture (if not ambient); (4) type and wavelength of radiationused; ( 5 ) space group symbol (if non-standard give relatedstandard setting); (6) measured density (I),,,), no.of moleculesin unit cell (Z), and calculated density (Ox) (with any implic-ations for ‘ molecular symmetry ’); (7) colour, size, and shapeof crystal used for data collection; (8) linear absorptioncoefficient (p).5.3 Data Collection and ProcessingThe description of data collection should contain sufficientinformation for the reliability of the determination to beassessed. The following should normally be included :(I) Type of diffractometer, measuring mode, and tempera-ture if not ambient (with reference if possible to an earlierfull description).(2) Theta range and reciprocal lattice segment.(3) Number of data measured, number observed, andI/o(I) criterion used (if more than one asymmetric unit isrecorded, the merging R value should be given).(4) Absorption correction and method used (with reference).( 5 ) Stability of intensity controls and any action taken,5.4 Structure Analysis and RefinementThe information provided should fulfil the same criteria asfor data collection (section 5.3).This would normallyinclude :(1) Method of solution (direct, heavy atom, or combin-ation) and development.(2) Mode of refinement (full matrix, blocked, blockdiagonal, anisotropic, isotropic, or mixed), treatment ofhydrogen atoms, and weighting scheme.(3) Final values of R and R, (and their definitions), witha statement of whether unobserved reflections were included(and if so, how), and if possible some estimate of the accuracyof the F, data.(4) Programs or packages and computers used (withreferences) and source off data (also f’, f”).( 5 ) Range of standard deviations for bond lengths andangles.(6) Any procedures used for definition of chirality (quot-ation of a single Hamilton ratio without specifying the Rvalues from which the ratio was derived, and the conditionsunder which these were obtained, will not normally beacceptable) .When the analysis has not been of a routine nature, authorsshould explain concisely all procedures used.5.5 Example of Presentationrecommendations in the preceding sections (5.2 to 5.4):The following example demonstrates the application of theNOTICE TO AUTHORSExperimentalCrystals were prepared as described in ref. 11 and sealedunder nitrogen in Lindemann capillaries.CVyStd Data.-C24H26CljRejSi6, M = 1 028.0.Mono-clinic, a = 12.021(3), b = 20.489(5), c = 18.194(5) A,p = 91.03(3)", V = 4 480 A3 (by least-squares refinementon diffractometer angles for 15 automatically centredreflections, h = 0.710 69 A), space group P2Jn (alt.P2,/c, No. 14), 2 = 4, D, = 1.76 g cm-j. Dark blue, air-sensitive tablets. Crystal dimensions (distance to facesfrom centre): 0.313(211,ZfT) x 0.163(010,0T0) x0.063(101,TOT) mm, ~(Mo-K,) = 85.12 cm-'.Data Collection and Proce~sing.'~-CAD4 diffracto-meter, w/28 mode with o scan width = 0.85 + 0.35 tan 8,w scan speed 1.3-6.8 deg min-', graphite-monochromatedMo-K, radiation; 6 383 reflections measured (1.5 < 8 <25", +h,k,l), 5 797 unique [merging R = 0.024 afterabsorption correction (max., min.transmission factors =0.37, O.lO)], giving 4 170 with I > 2cr(I). Linear andapprox. isotropic crystal decay, ca. 37%, corrected duringprocessing.Structure Analysis and Refinement.-Direct methods(Re and C1 atoms) followed by normal heavy atomprocedures. Full-matrix least squares refinement (intwo blocks for final, anisotropic cycles) with all non-hydrogen atoms anisotropic and hydrogens in calculatedpositions with one, overall, refined piso [= 0.08(2) A'].The weighting scheme w = 1/[02(Fo) + 0.OO78Fo2, witha(Fo) from counting statistics l2 gave satisfactory agree-ment analyses.Final R and R, values are 0.062, 0.064.Programs and computers used and sources of scatteringfactor data are given in ref. 12.References1 1 Ref. to prep of compound.12 For full details of experimental techniques used see ref.to previous paper giving full details of data collectionprocedures etc. used in author's laboratory.5.6 Presentation of Tables and DiagramsA clear distinction should be made between material toappear in print and material for deposition as a SupplementaryPublication (see section 4.0).5.6.1 For Publication in the Journal.-(1) A table of finalfractional atomic co-ordinates (labelled x , y , z) must beincluded. If the origin chosen differs from that adopted inInternational Tables this should be mentioned and justified.Where the asymmetric unit consists of a discrete molecule (ormolecules) co-ordinates should refer to atoms which are allin the same molecule.Hydrogen atom co-ordinates should beincluded only when experimentally determined or refined ;when they have been determined only by calculation, deposi-tion is appropriate (but not mandatory).(2) A table of selected bond lengths and angles, withestimated standard deviations. This should be restricted tosignificant dimensions only (for example it is rarely necessaryto include data for phenyl rings). Average values may begiven (with a range of e.s.d.s) for chemically equivalentgroups or for similar bonds.As an alternative to tabularpresentation it is often clearer to give important dimensionsin a structural diagram. Differences from expected normsshould be noted.(3) A conventional line drawing of the structure must beincluded except in the simplest cases and one perspectivediagram (or stereo pair) if appropriate. Packing diagramsshould not be included unless required to illustrate a specificchemical point. The atom numbering system should beclearly shown in one of the diagrams. Any differences fromthat required by standard rules of chemical nomenclatureshould be pointed out. Each atom of the asymmetric unitshould be assigned an arabic numeral in parentheses followingthe chemical symbol: C(2), 0(1"), etc.; it is often convenientto associate a particular number of primes with a particularasymmetric unit.Alternatively, roman numeral superscriptscan be employed: C(2') * C(2lv).5.6.2 For the Referees and/or for Deposition.-( 1) Any(2) A full list of bond lengths and angles with estimated(3) A full list of thermal parameters in the form BI, or(4) Details of any least squares planes used to provide( 5 ) A legible table of structure factors (Fo, F,) (for thecalculated co-ordinates (e.g. hydrogen).standard deviations.ur, (in A2 or pm').parameters for the paper.referees only; not for deposition).*5.6.3 Deposition of Material at the Cambridge Crystallo-graphic Data Centre.-The table of final fractional atomicco-ordinates and the full list of bond lengths and angles willalso be deposited at the Cambridge Data Centre (or at theUniversity of Bonn for molecules not containing ' organic 'carbon). These tables may be submitted as computer printout;the data need not be retyped if clearly legible. However, aprint program should be used which yields concise tables ofatomic and derived parameters. The content of the tablesshould be non-redundant and their interpretation immediatelyobvious.* Authors should preserve copies of structure factor tables in theirown records. During 1984-85 the Society will also keep copies inthe editorial office (photocopies available on request), in orderto assess the demand for this material.v

ISSN:1477-9226    

DOI:10.1039/DT98300000vb

出版商:RSC    

年代:1983

数据来源: RSC