The Crystal and Molecular Structure of the Dihydrochloride of 2-trans-6-Diethyl-2,4,4,6,8,8-hexamethylcyclotetraphosphazene

1975 ◽  
Vol 53 (16) ◽  
pp. 2413-2418 ◽  
Author(s):  
Harry P. Calhoun ◽  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Bond Length ◽  
Crystal And Molecular Structure ◽  
Chair Conformation ◽  
Electrostatic Repulsion ◽  
Electron Localization ◽  
Full Matrix ◽  
X Ray ◽  
Bond Lengths ◽  
The Mean

Octamethylcyclotetraphosphazene is deprotonated by methyllithium to form carbanions, which react with methyl iodide to give ethyl derivatives N4P4Me8−nEtn, [Formula: see text] the structure of the dihydrochloride of the diethyl derivative, N4P4Me6Et2•2HCl has been determined. Its crystals are monoclinic, a = 9.928(5), b = 15.482(6), c = 6.329(2) Å, β = 103.29(2)°, space group P21/n. The structure was determined from diffractometer X-ray data and refined by full-matrix least squares methods to R 0.079 for 715 observed reflections. The N4P4Me6Et2H22+ ion lies on a crystallographic center of symmetry and the eight-membered phosphazene ring has the "chair" conformation. There are two significantly different P—N bond lengths, 1.665(6) and 1.572(7) Å, and two significantly different P—N—P angles, 126.7(6) and 139.8(6)°. The mean P—C bond length is 1.801(7) Å, and the mean N—P—N and C—P—C angles are 112.2(4) and 107.6° respectively. Bond lengths and angles in the phosphazene ring show the characteristic effects of π-electron localization found in other protonated phosphazene derivatives. The two ethyl groups are in tran-antipodal positions, corresponding to the least intramolecular electrostatic repulsion in the carbanion.

The crystal and molecular structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, a phosphorus–silicon heterocycle

1979 ◽  
Vol 57 (2) ◽  
pp. 174-179 ◽  
Author(s):  
A. Wallace Cordes ◽  
Paul F. Schubert ◽  
Richard T. Oakley
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Single Bond ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Bond Lengths

The crystal structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space group P21/c, with a = 9.866(1), b = 11.921(1), and c = 11.324(2) Å, β = 104.31(1)°, Z = 2, and ρcalcd = 1.15 g/cm3. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.060 and Rw of 0.078, for 1173 reflections with intensities greater than 3σ. The (PhPSi2Me4)2 molecule lies on a crystallographic centre of symmetry, and the six-membered P2Si4 ring has a chair conformation with equatorial phenyl groups. The endocyclic angles at P (104.4(1)°) and Si (104.9(2)°) are intermediate between those found in cyclic hexaphosphine and hexasilane molecules, and the Si—Si and P—Si distances of 2.345(3) and 2.252(4) Å, respectively, correspond to single bond lengths, with no appreciable evidence for secondary pπ → dπ bonding between phosphorus and silicon. The Si—C (1.867(8) Å) and P—C (1.828(7) Å) bond lengths are also normal. The variations in the Si—P—C (101.6(2)°, 108.6(2)°), P—Si—C (range 106.2(3)–120.0(3)°), and Si—Si—C (range 105.8(3)–113.7(3)°) angles indicate that the positions of the exocyclic methyl and phenyl groups are influenced by both intra- and intermolecular steric forces.

Crystal and molecular structure of 4α-t-Butylcyclohexane-1β,2β-diol

1972 ◽  
Vol 25 (10) ◽  
pp. 2117 ◽  
Author(s):  
MD Brice ◽  
BR Penfold ◽  
WT Robinson
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Chair Conformation ◽  
Intensity Data ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
Full Matrix ◽  
X Ray ◽  
R Factor ◽  
Least Squares Techniques

The crystal and molecular structure of 4α-t-butylcyclohexane-1β,2,β-diol, C10H20O2, has been determined by X-ray diffraction methods. The compound crystallizes in the triclinic space group Pi with 4 molecules in a unit cell of dimensions a = 12.268, b = 15.921, c = 6.322�, α = 82.53, β = 114.45, γ = 111.13�. The intensity data were measured by counter methods using Cu Kα radiation; the structure was solved by means of the tangent formula, and was refined using full matrix least-squares techniques to a final R-factor of 0.063 for 1199 reflections. The crystal structure consists of two sets of crystallographically non-equivalent molecules hydrogen-bonded to form discrete chains parallel to the c axis. The cyclohexane rings are in the chair conformation.

scholarly journals Crystal and molecular structure of 2,2,4,6,6-pentamethyl-5-benzoyl-4-(N-methylbenzamido)-1,3-diaza-2,4,6(Pv)-triphosphorin

1977 ◽  
Vol 55 (13) ◽  
pp. 2534-2539 ◽  
Author(s):  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Bond Length ◽  
Least Squares ◽  
Crystal And Molecular Structure ◽  
Full Matrix ◽  
Bond Lengths ◽  
Benzoyl Group ◽  
Electron Withdrawal ◽  
Related Compounds ◽  
Twist Boat

Crystals of 2,2,4,6,6-pentamethyl-5-benzoyl-4-(N-methylbenzamido)-1,3-diaza-2,4,6(Pv)-tri-phosphorin are triclinic, a = 13.375(1), b = 11.313(1), c = 7.925(1) Å, α = 107.72(1), β = 98.23(1), γ = 87.00(1)°, Z = 2, space group [Formula: see text]. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures to a final R of 0.067 and Rw of 0.089 for 3954 reflections with. I ≥ 3σ(I) The P3N2C ring is nearly planar and has a conformation corresponding to a flattened version of the chair – twist boat. Bond lengths in the azaphosphorin ring, P—N, 1.579–1.614(2), and P—C, 1.752(3) and 1.777(3) Å, indicate conjugation with the C-benzoyl group. The exocyclic P—N bond length, 1.742(3) Å, is longer than those in related compounds as a result of competitive electron withdrawal from the N-benzoyl group. Other bond lengths (corrected for libration) are: mean P—Me, 1.796(4); C=O, 1.242(3) and 1.247(4); C—N, 1.472(3) and 1.369(4); mean C—C(phenyl), 1.391(10); other C(sp2)—C(sp2); 1.417–1.518(4) Å.

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 crystal and molecular structure of cis-dichloro(2,2′-o-phenylenebisbenzothiazole)copper(II)

1979 ◽  
Vol 57 (11) ◽  
pp. 1368-1371 ◽  
Author(s):  
Richard G. Ball ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Coordination Geometry ◽  
Full Matrix ◽  
X Ray ◽  
Square Planar ◽  
The Mean ◽  
Final Agreement ◽  
Cl Atoms ◽  
Least Squares Techniques

The molecular structure of cis-dichloro(2,2′-o-phenylenebisbenzothiazole)copper(II) has been determined by single crystal X-ray diffractometry. The crystal is monoclinic, P21/n, a = 8.408(1), b = 15.819(1), c = 14.229(2) Å, β = 93.19(1)°, and Z = 4. The structure has been refined by full-matrix least-squares techniques on F, using 3316 unique reflections for which F2 > 3σ(F2), to a final agreement factor of 0.028. The complex adopts an approximately square planar coordination geometry with the Cu bound to two cis Cl atoms and the N atoms of the chelating benzothiazole ligand. The mean Cu—N and Cu—Cl distances are 2.016(6) and 2.217(6) Å, respectively.

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.

Complexes of dodecamethylcyclohexaphosphazene with palladium(II) chloride and platinum(II) chloride. Crystal and molecular structure of cis-dichloro[η2-dodecamethylcyclohexaphosphazene (N,N′)] palladium(II) sesquihydrate

1981 ◽  
Vol 59 (16) ◽  
pp. 2429-2434 ◽  
Author(s):  
Norman L. Paddock ◽  
T. N. Ranganathan ◽  
Steven J. Rettig ◽  
Rajendra D. Sharma ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Bond Order ◽  
Nmr Spectra ◽  
Crystal And Molecular Structure ◽  
Model Calculations ◽  
Full Matrix ◽  
X Ray ◽  
Square Planar ◽  
The Mean ◽  
C Nmr

Dodecamethylcyclohexaphosphazene N6P6Me12, 1, forms 1:1 complexes with palladium(II) chloride, 2, and platinum(II) chloride, 3. Their 31P, 1H, and 13C nmr spectra show them to be rigid molecules in solution, with an approximate plane of symmetry. Crystals of 2 are orthorhombic, a = 17.4030(3), b = 15.4897(5), c = 10.7417(2) Å, Z = 4, space group P21212. The structure was determined from diffractometer X-ray data and refined by full-matrix least-squares methods to R = 0.031 for 3545 reflections with I ≥ 3σ(I). The metal atom has square planar coordination, and forms 6- and 10-membered chelate rings with the phosphazene ligand. The mean P—N bond length is 1.609 Å; the variation of bond lengths within the ring is consistent with model calculations of changes in bond order arising from the localization of bonding electrons.

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.

The cycloaddition of norbornadiene to (triphenylphosphoranediyl)aminocyclotrithiatriazene; the crystal and molecular structure of Ph3PN—S3N3•C7H8

1983 ◽  
Vol 61 (9) ◽  
pp. 2062-2067 ◽  
Author(s):  
Stephen W. Liblong ◽  
Richard T. Oakley ◽  
A. Wallace Cordes ◽  
Mark C. Noble
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Frontier Orbitals ◽  
Full Matrix ◽  
X Ray ◽  
X Ray Crystallography ◽  
Kinetics Of

The reaction of norbornadiene with (triphenylphosphoranediyl)aminocyclotrithiatriazene produces the cycloadduct Ph3PN—S3N3•C7H8. The crystal and molecular structure of this compound has been determined by X-ray crystallography. Crystals of Ph3PN—S3N3•C7H8 are monoclinic, space group P21/c, a = 9.757(1), b = 15.114(1), c = 16.535(2) Å, β = 100.73(1)°, V = 2395.7(9) Å3, and Z = 4. The structure was solved by direct methods and refined by Fourier and full-matrix least-squares procedures to give a final R of 0.040 and Rw of 0.058 for 2620 observed reflections. The structure reveals that the S3N3 ring adds to norbornadiene in an exo fashion via two sulphur atoms. The S3N3 ring adopts a chair conformation with the three ligands occupying axial positions on the same side of the ring. The relative rates of this and other cycloadditions involving SN substrates and olefins are discussed in terms of the energies of the interacting frontier orbitals. The results suggest that HOMO(olefin)–LUMO(SN substrate) interactions control the kinetics of these reactions.

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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