Crystal and molecular structure of hexamethylcyclotriphosphazene, (NPMe2)3

1977 ◽  
Vol 55 (24) ◽  
pp. 4206-4210 ◽  
Author(s):  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Molecular Dimensions

Crystals of hexamethylcyclotriphosphazene are monoclinic, a = 12.084(2), b = 13.426(1), c = 15.488(2) Å,β = 102.92(2)°, Z = 8, space group C2/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.045 and Rw of 0.060 for 1922 reflections with I ≥ 3σ(I). The six-membered phosphazene ring is slightly nonplanar and has a distorted chair conformation. Important molecular dimensions (bond lengths are corrected for libration) are: P—N, 1.599(2)–1.612(2), P—C, 1.796(3)–1.823(4) Å, N—P—N, 115.7(1)–117.9(1), P—N—P, 122.1(1)–122.9(1), and C—P—C, 101.8(2)-103.1(2)°.

Crystal and Molecular Structure of 4,4-Dimethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2- boranatacyclopentane

1974 ◽  
Vol 52 (14) ◽  
pp. 2531-2541 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter ◽  
W. Kliegel
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Van Der Waals ◽  
Direct Methods ◽  
Chair Conformation ◽  
Membered Ring ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of 4,4-dimethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boranatacyclopentane are orthorhombic, a = 17.043(3), b = 6.289(1), c = 13.024(2) Å, Z = 4, space group Pna21. The structure was determined by direct methods, and was refined by full-matrix least-squares procedures to R = 0.071 for 1100 reflections with I ≥ 3σ(I). Bond angles in the five-membered ring, which has a distorted half-chair conformation, range from 101.5(4) for OBO to 107.1(4)° for NOB. Bond lengths are: mean B—C, 1.632(8), B—O, 1.506(7) and 1.556(8), N—O, 1.409(5), C—O, 1.378(9), C—N, 1.467–1.509(7–10), mean C—C(aromatic), 1.395(25) Å. The structure consists of discrete molecules separated by normal van der Waals distances.

Crystal and molecular structure of difluoroboron N-methylacethydroxamate (2,2-difluoro-4,5-dimethyl-1,3-dioxa-4-azonia-2-boranatacyclopent-4-ene)

1977 ◽  
Vol 55 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter ◽  
W. Kliegel ◽  
D. Nanninga
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of difluoroboron N-methylacethydroxamate are monoclinic, a = 5.097(1), b = 10.653(2), c = 11.520(2) Å, β = 103.57(2)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.056 and Rw of 0.077 for 988 reflections with I ≥ 3σ(I). The structure features a planar five-membered BO2CN ring. Bond lengths (corrected for libration) are: B—F, 1.374(3) and 1.381(3), O—B, 1.496(3) and 1.497(3), O—N, 1.349(2), O—C, 1.346(2), C—N, 1.298(3) and 1.458(3), and C—C, 1.468(3) Å.

Crystal and molecular structure of L-prolinatodiphenylboron

1977 ◽  
Vol 55 (6) ◽  
pp. 958-965 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Conformational Disorder ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of L-prolinatodiphenylboron are monoclinic, a = 5.9427(5), b = 14.4633(7), c = 8.9654(4) Å, β = 98.423(8)°, Z = 2, space group P21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.037 and Rw of 0.053 for 1477 reflections with I ≥ 3σ(I). The proline ring exhibits conformational disorder. The crystal structure consists of discrete molecules linked by N—H … O hydrogen bonds (N … O = 2.893(3) Å) along the short a axis. Intramolecular N—B coordination occurs to form a system of two fused five-membered rings. Bond lengths (corrected for libration) are: N—B, 1.630(3), O—B, 1.529(3), O—C, 1.219(3) and 1.300(3), N—C, 1.506(3) and 1.507(3), C(sp3)–C(sp3), 1.525(4), C(sp2)—C(sp3), 1.517(3), and mean C—C(phenyl), 1.394 Å.

Crystal and molecular structure of diphenylboron N-methylacethydroxamate (4,5-dimethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopent-4-ene)

1978 ◽  
Vol 56 (12) ◽  
pp. 1676-1680 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter ◽  
W. Kliegel ◽  
D. Nanninga
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Heterocyclic Ring ◽  
Mirror Plane ◽  
Full Matrix ◽  
Space Group ◽  
Carbon And Nitrogen ◽  
Bond Lengths

Crystals of diphenylboron N-methylacethydroxamate are orthorhombic, a = 12.5478(8), b = 7.8735(3), c = 13.6809(5) Å, Z = 4, space group Pnam. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.037 and Rw = 0.054 for 1265 reflections with I ≥ 3σ(I). The molecule features a five-membered BO2CN ring which lies in the crystallographic mirror plane. The carbon and nitrogen atoms of the heterocyclic ring are positionally disordered. Mean bond lengths (corrected for libration) are: O—B, 1.550(2), B—C, 1.609(2), O—C/N, 1.340(3), C—N, 1.300(2), C/N—CH, 1.470(2), and C—C(phenyl), 1.394(8) Å.

Crystal and molecular structure of hexadecamethylcyclooctasiloxane, [(CH3)2SiO]8

1983 ◽  
Vol 61 (3) ◽  
pp. 541-544 ◽  
Author(s):  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Van Der Waals Interactions ◽  
Methyl Groups ◽  
Full Matrix ◽  
Bond Lengths ◽  
Rigid Conformation ◽  
Molecular Dimensions

Crystals of hexadecamethylcyclooctasiloxane are tetragonal, a = 13.9442(5), c = 8.5573(4) Å, Z = 2, space group P4/nnc. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.034 and Rw = 0.042 for 730 reflections with I ≥ 3σ(I). The molecular structure closely resembles that of [(CH3)2PN]8. Its comparatively rigid conformation, in which the silicon atoms form a crown, is dependent on the efficient use of van der Waals interactions between two sets of four methyl groups. Important molecular dimensions (bond lengths corrected for libration) are: Si—O = 1.629(1) and 1.635(1), Si—C = 1.862(2) and 1.848(3) Å, O—Si—O = 108.99(6), Si—O—Si = 157.8(1) and 148.8(2)°.

Crystal and Molecular Structure of B-Phenyl-diptychboroxazolidine,

1975 ◽  
Vol 53 (10) ◽  
pp. 1393-1401 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Thermal Motion ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths

Crystals of B-phenyl-dictychboroxazolidine are monoclinic, a = 8.4977(4), b = 9.0617(5), c = 7.0105(3) Å, β = 111.627(3)°, Z = 2, space group P21. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.040 for 967 reflections with I ≥ 3σ(I). The bond lengths involving nonhydrogen atoms have been corrected for thermal motion. Bond lengths are: B—O, 1.460(3) and 1.474(3), B—N, 1.666(3), B—C, 1.613(3), C—O, 1.411(3) and 1.419(3), C—N, 1.485(3) and 1.486(3), C(sp3)—C(sp3), 1.514(4) and 1.524(4), C—C(ar), 1.384–1.400(4–6), mean C—H, 0.98(4), and N—H, 0.87(5) Å. The crystal structure consists of discrete molecules of B-phenyl-diptychboroxazolidine each linked to two others by N—H … O hydrogen bonds (O … N = 2.914(3) Å) to form continuous spirals along b.

Crystal and molecular structure of hexadecamethylcyclooctaphosphazene, (NPMe2)8

1977 ◽  
Vol 55 (13) ◽  
pp. 2530-2533 ◽  
Author(s):  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Membered Ring ◽  
Weighted Mean ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

Crystals of hexadecamethylcyclooctaphosphazene are tetragonal, a = 13.637(1), c = 8.215(1) Å, Z = 2, space group P4/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.033 and Rw of 0.032 for 1306 reflections with I ≥ 4σ(I) The molecule has crystallographic fourfold (C4) symmetry with weighted mean bond lengths P—N, 1.590(13), P—C, 1.811(2), and C—H, 0.95(2) Å (those not involving hydrogen have been corrected for libration, rms deviations from the mean are given in parentheses). Angles in the 16-membered ring are 119.2(1) and 115.1(1)° at P and 131.5(1) and 148.2(1)° at N.

The preparation and the crystal and molecular structure of tetradecamethylcycloheptaphosphazene, (NPMe2)7

1977 ◽  
Vol 55 (2) ◽  
pp. 304-309 ◽  
Author(s):  
Keith D. Gallicano ◽  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Membered Ring ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
The Mean

The preparation of tetradecamethylcycloheptaphosphazene, by the methylation of the corresponding fluorophosphazene (NPF2)7 with methylmagnesium bromide, is reported. Crystals of tetradecamethylcycloheptaphosphazene are monoclinic, a = 13.160(1), b = 11.685(1), c = 18.576(1) Å, (β = 108.333(5)°, Z = 4, space group C2/c. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.046 and Rw of 0.063 for 2568 reflections with I ≥ 3σ(I). The molecule has crystallographic C2 symmetry with mean bond lengths (rms deviations from the mean in parentheses, bonds not involving hydrogen have been corrected for libration) P—N, 1.592(6), P—C, 1.804(11), and C—H, 0.94(7) Å, and mean angles in the 14-membered ring are 132.9° at N and 117.1° at P.

Crystal and molecular structure of 1,1′-bi(3,3,4,4-tetrafluoro-2-diphenylphosphinocyclobutene)

1977 ◽  
Vol 55 (17) ◽  
pp. 3065-3070 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Molecular Symmetry ◽  
Full Matrix ◽  
Space Group ◽  
Bond Lengths ◽  
Good Agreement

Crystals of 1,1′-bi(3,3,4,4-tetrafluoro-2-diphenylphosphinocyclobutene) are monoclinic, a = 10.398(1), b = 18.484(1), c = 15.984(1) Å, β = 107.76(1)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.042 and Rw of 0.057 for 4226 reflections with I ≥ 3σ(I). The molecule has a cisoid configuration about the central C—C bond, the angle between the two cyclobutene rings being 34.3°. The overall molecular symmetry is approximately C2 with a P … P separation of 3.661(1) Å. Bond lengths and angles in the molecule are generally in good agreement with accepted values.

Crystal and Molecular Structure of B,B- Diphenylboroxazolidine (2-Aminoethyl Diphenylborinate),

1973 ◽  
Vol 51 (8) ◽  
pp. 1288-1294 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Electron Density ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Full Matrix ◽  
Bond Lengths

Crystals of the title compound are monoclinic, a = 13.840(1), b = 8.9169(5), c = 10.170(1) Å, β = 98.85(1)°, Z = 4, space group P21/n. The structure was determined by direct methods, and refined by electron-density and full-matrix least-squares procedures to R 0.041 for 1458 observed reflections. The five-membered boroxazolidine ring is in the half-chair conformation. Bond angles in the ring range from 99.7° for OBN to 110.1° for BOC. Bond lengths are as follows: mean B—C, 1.611(2), B—N, 1.653(3), B—O, 1.484(3), C—N, 1.485(3), C—O, 1.413(3), mean C—C (aromatic), 1.383(11), and C—C, 1.505(4) Å. The structure consists of discrete molecules linked by O…H—N hydrogen bonds (2.874(2) Å) to form continuous spirals about the 21 axes.

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