N,N-Ethylenebis(salicylideneimine) derivatives of gallium trimethyl: crystal and molecular structure of N,N-ethylenebis(salicylideneiminato) bis(dimethylgallium)

1977 ◽  
Vol 55 (13) ◽  
pp. 2540-2546 ◽  
Author(s):  
Kenneth S. Chong ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter

Crystals of N,N-ethylenebis(salicylideneiminato)bis(dimethylgallium) are orthorhombic, a = 22.781(1), b = 9.4869(6), c = 19.700(2) Å, Z = 8, space group Pbca. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.036 and Rw of 0.029 for 2248 reflections with I ≥ 3σ(I). Details of the preparation and physical properties of (C16H14N2O2)(GaMe2)2 and (C16H15N2O2)(GaMe2) are given. The (C16H14N2O2)(GaMe2)2 molecule is approximately centrosymmetric in the solid state. A "GaMe2" unit is coordinated to each of the two salicylideneiminato moieties of the N,N-ethylenebis(salicylideneiminato) ligand. The gallium atoms have a distorted tetrahedral coordination geometry, with bond angles at gallium ranging from 92.7(1) to 124.6(3)°. Important bond lengths (corrected for libration) are: Ga—O, 1.886(2) and 1.884(2), Ga—N, 2.033(3) and 2.042(3), and weighted mean Ga—C, 1.959(9) Å.


1979 ◽  
Vol 57 (14) ◽  
pp. 1823-1825 ◽  
Author(s):  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter

Crystals of bis[methyltris(1-pyrazolyl)gallato]nickel(II) are rhombohedral, a = 9.6670(5), c = 23.893(1) Å, Z = 3, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.030 and Rw = 0.035 for 925 reflections with I ≥ 3σ (I). The crystal structure consists of well separated molecules of [MeGa-(N2C3H3)3]2Ni having exact [Formula: see text] (S6) symmetry and approximate D3d symmetry. The coordination geometry about the nickel atom is octahedral with Ni—N = 2.109(2) Å, N—Ni—N = 90.65(6) and 89.35(6)°. The gallium atom has distorted tetrahedral coordination geometry with Ga—N = 1.939(2), Ga—C = 1.940(4) Å, N—Ga—N = 99.55(6), and N—Ga—C = 118.16(5)°.



1982 ◽  
Vol 60 (15) ◽  
pp. 2017-2022 ◽  
Author(s):  
Katherine W. Oliver ◽  
Steven J. Rettig ◽  
Robert C. Thompson ◽  
James Trotter

The preparation, magnetic properties, electronic and infrared spectra, and molecular structure of poly-bis(μ-diethylphosphinato)copper(II) are described. Crystals of poly-bis(μ-diethylphosphinato)copper(II) are triclinic, a = 7.700(1), b = 9.807(1), c = 10.101(1) Å, α = 90.48(1), β = 104.77(1), γ = 112.21(1)°, Z = 2, space group [Formula: see text]. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.025 and Rw = 0.032 for 3491 reflections with I ≥ 3σ(I). The polymeric structure consists of Cu atoms with flattened tetrahedral coordination geometry linked by double phosphinate bridges. Mean bond lengths (corrected for libration) are: Cu—O, 1.924(3), P—O, 1.526(4), and P—C, 1.807(4) Å. Assignment of the electronic spectrum using a crystal field model gives Dq = 1665 cm−1 and Cp = 1800 cm−1. Magnetic susceptibility studies give no evidence for magnetic concentration over the temperature range 80 to 300 K.



1981 ◽  
Vol 59 (3) ◽  
pp. 518-523 ◽  
Author(s):  
Kenneth S. Chong ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter

The Cu(I) complex [Me2Ga(OCH2CH2NMe2)N2C5H7]Cu•PPh3 has been synthesized and its fluxional behavior in solution probed. Attempts have been made to isolate the analogous Cu(I) carbonyl complex. Crystals of [dimethyl(3,5-dimethyl-1-pyrazolyl)(N,N-dimethylethanolamino)gallato (N(2),O,N(3))](triphenylphosphine)copper(I) are monoclinic, a = 18.871(2), b = 9.464(1), c = 18.374(2) Ā, β = 109.62(1)°, Z = 4, space group P21/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.028 and Rw = 0.035 for 2729 reflections with I ≥ 3σ(I). The copper atom is bonded to the phosphine and to the tridentate Me2Ga(OCH2CH2NMe2)N2C5H7− ligand resulting in a distorted tetrahedral coordination geometry. The Cu—P distance of 2.156(1) Å is unusually short. Other important bond distances (corrected for libration) are: Cu—O, 2.163(2), Cu—N(pyrazolyl), 2.025(3), Cu—N(amino), 2.144(3), Ga—O, 1.896(3), Ga—N, 2.005(3), and Ga—C, 1.972(5) and 1.987(5) Å.



1977 ◽  
Vol 55 (13) ◽  
pp. 2530-2533 ◽  
Author(s):  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter

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.



1977 ◽  
Vol 55 (24) ◽  
pp. 4174-4179 ◽  
Author(s):  
Kenneth R. Breakell ◽  
Steven J. Rettig ◽  
Alan Storr ◽  
James Trotter

Crystals of L-prolinatodimethylgallium are orthorhombic, a = 10.624(2), b = 10.567(4), c = 8.2268(6) Å, Z = 4, space group P212121. The structure was solved by direct methods and was refined by full-matrix least squares procedures to a final R of 0.029 and Rw of 0.035 for 1109 reflections with I ≥ 3σ(I). Details of the preparation and physical properties of L-prolinatodimethylgallium and L-prolinatodiethylgallium are given. The crystal structure of L-prolinatodimethylgallium consists of molecules each linked to two others by weak Ga—O bonds (2.695(3) Å) and N—H … O hydrogen bonds (N … O = 2.901(4) Å) to form a chain-like polymeric structure extending along the b axis. The gallium atom is five-coordinate and has distorted trigonal bipyramidal geometry. Important bond lengths are: Ga—O (axial), 2.044(3) and 2.695(3); Ga—N, 2.035(3); and Ga—C, 1.942(5) and 1.958(5) Å



1976 ◽  
Vol 54 (7) ◽  
pp. 1168-1175 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter

Crystals of (salicylaldehydato)diphenylboron are orthorhombic, a = 11.6548(5), b = 16.2983(5), c = 8.0806(2) Å, Z = 4, space group Pna21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.051 for 1386 reflections with I ≥ 3σ(I). The BO2C3 ring has a distorted 'sofa' conformation. Bond lengths in the molecule (those not involving hydrogen atoms have been corrected for thermal motion) are: C—O, 1.263(4) and 1.334(4), B—O, 1.500(4) and 1.574(4), C—B, 1.603(5) and 1.610(5), C—C(salicylaldehyde), 1.368–1.423(5–8), C—C(phenyl), 1.352–1.413(5–11), and weighted mean C(sp2)—H, 0.96 Å.



1977 ◽  
Vol 55 (17) ◽  
pp. 3118-3123 ◽  
Author(s):  
Richard T. Oakley ◽  
Norman L. Paddock ◽  
Steven J. Rettig ◽  
James Trotter

Crystals of dodecamethylcyclohexaphosphazene are triclinic, a = 13.898(1), b = 8.690(1), c = 10.790(1) Å, α = 109.84(1), β = 92.01(1), γ = 106.39(1)°, Z = 2, space group [Formula: see text]. 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 of 0.042 for 4217 reflections with I ≥ 3σ(I). The unit cell contains two independent centrosymmetric molecules which are virtually identical. The 12-membered rings have the 'double tub' conformation. Bond lengths not involving hydrogen have been corrected for libration. Weighted mean bond lengths (rms deviations from the mean in parentheses) are: P—N, 1.593(6), C—P, 1.808(4), and C—H, 0.95(6) Å.



1976 ◽  
Vol 54 (20) ◽  
pp. 3130-3141 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter

Crystals of B,B-bis(p-tolyl)boroxazolidine, 1c, are trigonal, a = 25.1028(9), c = 12.4184(7) Å, Z = 18, space group [Formula: see text]. And crystals of B,B-diphenylboroxazolidine, 1a, are orthorhombic, a = 17.6420(4), b = 14.2527(3), c = 10.205(1) Å, Z = 8, space group Pbca. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.057 and 0.040 for 2230 and 1828 reflections with I ≥ 3σ(I) respectively. Both molecules have structures similar to related compounds and feature intermolecular N—H … O hydrogen bonds (N … O = 2.982(2) for 1c and 2.896(2) Å for 1a). Bond lengths are: for 1c; O—C, 1.413(3), O—B, 1.478(3), N—C, 1.488(3), N—B, 1.657(3), C(sp3)—C(sp3), 1.501(4), B—C, 1.616(3) and 1.623(3), mean C—C(ar), 1.395, N—H, 0.93(2) and 0.94(2), mean C(sp3)—H, 1.00, and mean C(ar)—H, 1.00 Å; for 1a; O—C, 1.409(2), O—B, 1.476(2), N—C, 1.489(2), N—B, 1.655(2), C(sp3)—C(sp3), 1.507(3), B—C, 1.613(2) and 1.620(2), mean C—C(ar), 1.391, N—H, 0.93(2) and 0.92(2), mean C(sp3)—H, 1.00, and mean C(ar)—H, 0.98 Å. A statistical analysis of the phenyl C—C distances in compounds 1a, 1b, and 1c has provided an example of statistically significant substituent-induced bond length variation in the phenyl rings.



Author(s):  
M. Bidya Sagar ◽  
K. Ravikumar ◽  
Y. S. Sadanandam

AbstractThe crystal structures of two dihydropyridines were solved by direct methods and refined by full-matrix least-squares procedure. 2,6-Dimethyl-3,5-di[N-methyl]-carbamoyl-4-[3,4-methoxy]phenyl-1,4-dihydropyridine hemihydrate, CBoth compounds crystallize with two molecules in the asymmetric unit. In compound



1989 ◽  
Vol 67 (11) ◽  
pp. 1959-1963 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Steven J. Rettig ◽  
James Trotter

The reaction of N,N′-dihydroxy-N,N′-dimethylmethanediamine with phenylboronic acid leads to the product 1,7-dimethyl-3,5-diphenyl-2,4,6-trioxa-7-aza-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane rather than the expected product 1,5-dimethyl-3-phenyl-1,5-diaza-2,4-dioxa-3-boracyclohexane. The structure of N,N′-dihydroxy-N,N′-dimethylmethanediamine has been determined and is discussed in terms of its reaction with PhB(OH)2. Crystals of N,N′-dihydroxy-N,N′-dimethylmethanediamine are tetragonal, a = 8.5346(3), c = 8.4178(7) Å, Z = 4, space group P421c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.036 and Rw of 0.038 for 333 reflections with I ≥ 3σ(I). The structure consists of hydrogen-bonded dimers having exact [Formula: see text] symmetry. Keywords: N,N′-dihydroxy-N,N′-dimethylmethanediamine, crystal structure.



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