International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C, ch. 9.5, p. 794
https://doi.org/10.1107/97809553602060000621

Appendix A9.5.1. Notes to Table 9.5.1.1[link]

F. H. Allen,a D. G. Watson,a L. Brammer,b A. G. Orpenc and R. Taylora

aCambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, England,bDepartment of Chemistry, University of Missouri–St Louis, 8001 Natural Bridge Road, St Louis, MO 63121-4499, USA, and cSchool of Chemistry, University of Bristol, Bristol BS8 1TS, England

  • (1)  Sample dominated by B—CH3. For longer bonds in B—CH3, see LITMEB10 [B(4)—CH3 = 1.621–1.644 Å].

  • (2)  p(π)—p(π) bonding with Bsp2 and Nsp2 coplanar (τBN = 0 ± 15°) predominates. See G. Schmidt, R. Boese & D. Bläser [Z. Naturforsch. Teil B (1982), 37, 1230–1233].

  • (3)  84 observations range from 1.38 to 1.62 Å and individual values depend on substituents on B and O. For a discussion of borinic acid adducts, see S. J. Rettig & J. Trotter [Can. J. Chem. (1982), 60, 2957–2964].

  • (4)  See M. Kaftory (1983). [In The chemistry of functional groups. Supplement D: The chemistry of halides, pseudohalides and azides, Part 2, Chap. 24, edited by S. Patai & Z. Rappoport. New York: John Wiley.]

  • (5)  Bonds that are endocyclic or exocyclic to any three- or four-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 nine subgroups is 1.538 (σ = 0.022) Å.

  • (7)  See (a) F. H. Allen [Acta Cryst. (1980), B36, 81–96] and (b) F. H. Allen [Acta Cryst. (1981), B37, 890–900].

  • (8)  See F. H. Allen [Acta Cryst. (1984), B40, 64–72].

  • (9)  See F. H. Allen [Tetrahedron (1982), 38, 2843–2853].

  • (10)  See F. H. Allen [Tetrahedron (1982), 38, 645–655].

  • (11)  Cyclopropanones and cyclobutanones excluded.

  • (12)  See W. B. Schweizer & J. D. Dunitz [Helv. Chim. Acta (1982), 65, 1547–1554].

  • (13)  See L. Norskov-Lauritsen, H.-B. Bürgi, P. Hoffmann & H. R. Schmidt [Helv. Chim. Acta (1985), 68, 76–82].

  • (14)  See P. Chakrabarti & J. D. Dunitz [Helv. Chim. Acta (1982), 65, 1555–1562].

  • (15)  See J. L. Hencher (1978). [In The chemistry of the C[triple bond]C triple bond, Chap. 2, edited by S. Patai. New York: John Wiley.]

  • (16)  Conjugated: torsion angles about central C—C single bond is 0 ± 20° (cis) or 180 ± 20° (trans).

  • (17)  Unconjugated: torsion angle about central C—C single bond is 20–160°.

  • (18)  Other conjugative substituents excluded.

  • (19)  TCNQ is tetracyanoquinodimethane (see diagrams).

  • (20)  No difference detected between C2[\ddb]C3 and C3[\ddb]C4 bonds.

  • (21)  Derived from neutron diffraction results only.

  • (22) Nsp3: pyramidal; mean valence angle at N is in the range 108–114°.

  • (23) Nsp2: planar; mean valence angle at N is ≥ 117.5°.

  • (24) Cyclic and acyclic peptides.

  • (25) See R. H. Blessing [J. Am. Chem. Soc. (1983), 105, 2776–2783].

  • (26) See L. Lebioda [Acta Cryst. (1980), B36, 271–275].

  • (27) n = 3 or 4; i.e. tri- or tetrasubstituted ureas.

  • (28) Overall value also includes structures with mean valence angle at N in the range 115–118°.

  • (29) See F. H. Allen & A. J. Kirby [J. Am. Chem. Soc. (1984), 106, 6197–6200].

  • (30) See A. J. Kirby (1983). [The anomeric effect and related stereoelectronic effects at oxygen. Berlin: Springer.]

  • (31) See B. Fuchs, L. Schleifer & E. Tartakovsky [Nouv. J. Chim. (1984), 8, 275–278].

  • (32) See S. C. Nyburg & C. H. Faerman [J. Mol. Struct. (1986), 140, 347–349].

  • (33) Sample dominated by P—CH3 and P—CH2—C.

  • (34) Sample dominated by C* = methyl.

  • (35) See A. Kálmán, M. Czugler & G. Argay [Acta Cryst. (1981), B37, 868–877].

  • (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 [{\rm O} \cdots {\rm H} \cdots {\rm O}] 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 the range 100–113.5°; N planar has average angle ≥ 117.5°.

  • (41) See R. R. Holmes & J. A. Deiters [J. Am. Chem. Soc. (1977), 99, 3318–3326].

  • (42) No detectable variation in S=O bond length with type of C substituent.








































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