Dinuclear cobalt(II) complexes of a polyhydroimidazole ligand. Dinuclear (2:1) non-metallocyclic derivatives and dinuclear (1:1) metallocyclic complexes with a large, unoccupied central cavity

1992 ◽  
Vol 70 (11) ◽  
pp. 2771-2776 ◽  
Author(s):  
Santokh S. Tandon ◽  
Laurence K. Thompson ◽  
John N. Bridson ◽  
John C. Dewan
Keyword(s):  
Least Squares ◽  
Bidentate Ligand ◽  
Unit Cell ◽  
Molecular Structures ◽  
Central Cavity ◽  
Monoclinic System ◽  
Full Matrix ◽  
Space Group ◽  
Cell Refinement ◽  
Compound Ii

The ligand BTIM (1,2,4,5-tetrakis(4,5-dihydro-imidazol-2-yl)benzene) reacts with cobalt(II) salts to form two series of complexes. The 1:1, dinuclear, metallocyclic derivatives [Co2(BTIM)2X2]X2 (X = Cl (I), Br (II)) involve two bis-dentate ligands in a metallocyclic structure with a large unoccupied cavity. The 2:1, binuclear derivatives [Co2(BTIM)X4] (X = Cl (III), Br (IV)) involve two metals bound to a single, bis-bidentate ligand. The crystal and molecular structures of II and III are reported. Compound II crystallized in the monoclinic system, space group P21/c, with a = 13.642(6) Å, b = 11.560(3) Å, c = 18.406(7) Å, β = 101.73(3)° and four formula units per unit cell. Refinement by full-matrix least squares gave final residuals of R = 0.060 and Rw = 0.062. Compound III crystallized in the triclinic system, space group [Formula: see text], with a = 8.367(2) Å, b = 14.254(3) Å, c = 7.649(2) Å, α = 100.99(2)°, β = 101.44(2)°, γ = 106.85(1)° and one formula per unit cell. Refinement by full-matrix least squares gave final residuals of R = 0.052 and Rw = 0.045. In the metallocyclic structure (II) the square-pyramidal cobalt(II) centres are separated by 7.599(4) Å, while in the 2:1 derivative the two tetrahedral cobalt(II) centres have a much larger separation (8.736(3) Å).

Structure cristalline et moléculaire du cyclopentadiényle dicarbonyle dioxyde de soufre manganèse MnC5H5(CO)2SO2

1973 ◽  
Vol 51 (22) ◽  
pp. 3684-3689 ◽  
Author(s):  
Claude Barbeau ◽  
Ram Janam Dubey
Keyword(s):  
Least Squares ◽  
Average Distance ◽  
Unit Cell ◽  
Monoclinic System ◽  
Full Matrix ◽  
Space Group ◽  
Cyclopentadienyl Complexes ◽  
Distance Formula

The compound MnC5H5(CO)2SO2 crystallizes in the monoclinic system, space group P21/c, in a unit cell of dimensions a = 10.98(2) Å, b = 10.63(2) Å, c = 7.43(2) Å, β = 100.75(8)° with Z = 4. The structure was determined from 1512 reflections obtained on films from a precession camera; the residual factor, R, was 0.093 after a full matrix least-squares refinement. The Mn–S bond seems very strong having a length (2.037(5) Å) which is smaller than the sum of the covalent radii by 0.3 Å The average distance [Formula: see text] is less than that usually observed in manganese–cyclopentadienyl complexes. The two CO groups are distinct. The instability of the complex might be explained, in part, by the crowding of the SO2 and CO ligands. [Journal translation]

Studies in aryltin chemistry. Part 6. Crystal and molecular structures of tetra(p-methylsulphonylphenyl)tin(IV) and tetra(p-methylsulphinylphenyl)tin(IV) monohydrate

1990 ◽  
Vol 68 (8) ◽  
pp. 1277-1282 ◽  
Author(s):  
Ivor Wharf ◽  
Michel G. Simard ◽  
Henry Lamparski
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Direct Method ◽  
Molecular Structures ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Molecular Symmetry ◽  
Asymmetric Unit ◽  
Full Matrix ◽  
Space Group

Tetrakis(p-methylsulphonylphenyl)tin(IV) and tetrakis(p-methylsulphinylphenyl)tin(IV) n-hydrate have been prepared and their spectra (ir 1350–400 cm−1; nmr, 1H, 13C, 119Sn) and X-ray crystal structures are reported. The first compound is monoclinic, space group C2/c, Z = 4, with a = 21.589(6), b = 6.207(3), c = 22.861(11) Å, β = 93.80(3)° (22 °C); the structure was solved by the direct method and refined by full-matrix least squares calculations to R = 0.043 for 2755 observed reflections. It has 2 molecular symmetry with the methyl group and one oxygen atom completely disordered in both CH3S(O2) groups in the asymmetric unit. The second compound is tetragonal, space group P42/n, Z = 2, with a = b = 15.408(6), c = 6.379(2) Å (−100 °C); the structure was solved by the Patterson method and refined by full-matrix least squares calculations to R = 0.060 for 1209 observed reflections. It has [Formula: see text] molecular symmetry with the whole asymmetric unit disordered. Water molecules occupy positions on parallel 42 axes but molecular packing requirements prevent all sites having 100% occupancy giving n ~ 1 for the hydrate. Keywords: Tetra-aryltins, crystal structures, sulphone, sulphoxide, hydrogen-bonding.

Refinement of the structure of Mg2As2O7

1970 ◽  
Vol 48 (6) ◽  
pp. 890-894 ◽  
Author(s):  
C. Calvo ◽  
K. Neelakantan
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Least Squares ◽  
Unit Cell ◽  
Full Matrix ◽  
Space Group ◽  
Cell Dimensions ◽  
Central Oxygen ◽  
R Value ◽  
Unit Cell Dimensions

The crystal structure of Mg2As2O7 has been refined by full matrix least squares procedures using 587 observed reflections. The structure of Mg2As2O7 is of the thortveitite type, as reported by Łukaszewicz, with space group C2/m and unit cell dimensions a = 6.567(2) Å, b = 8.524(4) Å, c = 4.739(1) Å, β = 103.8(1)°, and Z = 2. The As—O—As group in the anion appears to be linear but the central oxygen atom undergoes considerable disorder in the plane perpendicular to this group. The AsO bond distances uncorrected for thermal motion are 1.67 Å for the As—O(—As) bond and 1.66 and 1.65 Å for the terminal As—O bonds. The final R value obtained is 0.088.

Aromatic aldonitrones of 2-(hydroxyamino)benzyl alcohol and their cyclic isomers. Crystal and molecular structures of a 1-hydroxy-1,2-dihydro-4H-3,1-benzoxazine, a boron chelate, and its parent nitrone ligand

1998 ◽  
Vol 76 (4) ◽  
pp. 389-399 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Jörg Metge ◽  
Steven J Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Benzyl Alcohol ◽  
Crystal Structures ◽  
Direct Methods ◽  
Molecular Structures ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Independent Molecules ◽  
Boron Chelate

The synthesis of a series of C-aryl-N-[2-(hydroxymethyl)phenyl]nitrones, 5 (that can also exist under certain conditions as isomeric 1-hydroxy-2-aryl-1,2-dihydro-4H-3,1-benzoxazines, 8), via 2-(hydroxyamino)benzyl alcohol, 4, and their subsequent reactions with oxybis(diphenylborane), (Ph2B)2O, leading to the 5-(arylmethylene)-7,7-diphenyl-6,8-dioxa- 5-azonia-7-borata-5H-6,7,8,9-tetrahydrobenzocyclo- heptenes 6 are described. Crystals of 1-hydroxy-2- (4-methoxyphenyl)- 1,2-dihydro-4H-3,1-benzoxazine, 8b, are monoclinic, a = 9.379(2), b = 10.699(2), c = 12.9392(7) Å, β = 99.916(2)°, Z = 4 (two independent molecules), space group Pa; those of C-[4-(dimethylamino)phenyl]-N-[(2-hydroxymethyl)phenyl]nitrone, 5c, are monoclinic, a = 7.687(1), b = 7.891(1), c = 11.5053(9) Å, β = 92.781(9)°, Z = 2, space group P21; and those of 5-[4-(dimethylamino)phenylmethylene]-7,7-diphenyl-6,8-dioxa-5-azonia-7-borata-5H-6,7,8,9- tetrahydro-benzocycloheptene, 6a, are monoclinic, a = 10.771(1), b = 13.1057(9), c = 16.8724(7) Å, β = 90.005(5)°, Z = 4, space group P21/n. The structures were solved by direct methods and refined by full-matrix least-squares procedures to R(F2) = 0.120 (Rw(F2) = 0.135) for all 3149 reflections (R(F) = 0.071, Rw(F) = 0.063 for 1500 reflections with I >3 σ (I)) for 8b and R(F) = 0.035 and 0.036 (Rw(F) = 0.031 and 0.038) for 1071 and 3594 reflections with I >3 σ (I), respectively, for 5c and 6a. Compound 8b is the first structurally characterized 1-hydroxy-1,2-dihydro-4H-3,1-benzoxazine derivative and 6a features a relatively rare seven-membered boron-containing heterocycle.Key words: C-aryl-N-[2-(hydroxymethyl)phenyl]nitrones, 1-hydroxy-2-aryl-1,2-dihydro-4H-3,1-benzoxazines, organoboron compounds, crystal structures

Structural studies of organoboron compounds. XV. Crystal and molecular structures of (3-aminopropanolato)diphenylboron, (2-N,N-dimethylaminoethanolato)diphenylboron, and (2-N,N-dimethylaminoethanolato)diphenylboron – diphenylborinic acid (1:1)

1983 ◽  
Vol 61 (10) ◽  
pp. 2334-2340 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Boron Atom ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures

Crystals of (3-aminopropanolato)diphenylboron are monoclinic, a = 9.6717(13). b = 9.8867(6), c = 14.452(2) Å, β = 99.500(7)°, Z = 4, space group P21/n: those of (2-N,N-dimethylaminoethanolato)diphenylboron are monoclinic, a = 7.0721(4), b = 16.8829(4), c = 12.0975(8) Å, β = 97.875(3)°, Z = 4, space group Cc; and those of (2-N,N-dimethylaminoethanolato)diphenylboron – diphenylborinic acid (1:1) are monoclinic. a = 11.3231(10). b = 19.3190(12). c = 12.2451(11) Å, β = 109.321(4)°, Z = 4, space group P21/n. All three structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.038. 0.031, and 0.040 for 1522, 1649, and 2420 reflections with I ≥ 3σ(I) respectively. Each structure contains a tetrahedrally coordinated boron atom. The libration-corrected B—O, B—N, and mean B—C distances are: 1.481(2), 1.643(3), and 1.623(3) Å for (3-aminopropanolato)diphenylboron; 1.476(2), 1.691 (2), and 1.625(7) Å for (2-N,N-dimethylaminoethanolato)diphenylboron. The Ph2BOH molecule contains a trigonal-planar boron atom with B—O = 1.354(3) Å and mean B—C = 1.572(3) Å.

Structural studies of organoboron compounds. XVI. Preparation and crystal and molecular structures of 4,4-dimethyl-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane and 4,4,5,5-tetramethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane

1984 ◽  
Vol 62 (5) ◽  
pp. 838-844 ◽  
Author(s):  
W. Kliegel ◽  
H.-W. Motzkus ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Physical Properties ◽  
Least Squares ◽  
Steric Hindrance ◽  
Direct Methods ◽  
Structural Features ◽  
Molecular Structures ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures

Details of the synthesis, physical properties, and molecular structures of 4,4-dimethyl-2,5,5-triphenyl-1,3-dioxa-4-azonia-2-bora-5-boratacyclopentane, 4, and 4,4,5,5-tetramethyl-2,2-diphenyl-1,3-dioxa-4-azonia-2-boratacyclopentane, 5, are reported. Crystals of 4 are triclinic, a = 9.841(2), b = 14.722(3), c = 6.6701(12) Å, α = 86.79(1), β = 102.95(1), γ = 93.89(1)°, Z = 2, space group [Formula: see text]; and those of 5 are monoclinic, a = 14.9164(12), b = 6.4732(3), c = 18.2248(15) Å, β = 117.263(3)°, Z = 4, space group Cc. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.032 and 0.035 for 1456 and 1649 observed reflections, respectively. Molecules of 4 contain non-planar BOBON rings with an unusually long N(sp3)—B(sp3) distance of 1.728(3) Å and in 5 there is a long N(sp3)—C(sp3) bond of 1.591(3) Å. These structural features are ascribed to steric hindrance.

The Crystal and Molecular Structures of the 3,5-Dimethylpyrazolylgallium dimethyl dimer, [Me2Ga·N2C5H7]2, and the Hydroxy-bridged Species, [Me2Ga(OH)(N2C5H7)GaMe2·2N2C5H8]

1975 ◽  
Vol 53 (19) ◽  
pp. 2944-2954 ◽  
Author(s):  
David F. Rendle ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Membered Ring ◽  
Molecular Structures ◽  
Methyl Groups ◽  
Central Feature ◽  
Fourier Methods ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
The Mean

Crystals of the 3,5-dimethylpyrazolylgallium dimethyl dimer [Me2Ga·N2C5H7]2 (1a) are monoclinic, a = 8.660(3), b = 13.776(1), c = 8.443(2) Å, β = 112.45(2)°, Z = 2, space group P21/c, and crystals of the hydroxy-bridged species [Me2Ga(OH)(N2C5H7)GaMe2·2N2C5H8] (1b) are monoclinic, a = 28.778(3), b = 9.098(3), c = 20.222(2) Å, β = 100.72(1)°, Z = 8, space group C2/c. Both structures were solved by Patterson and Fourier methods and were refined by full-matrix least-squares methods to final R values of 0.071 and 0.045 for 1443 and 2746 reflections with I ≥ 3σ(I) respectively. Molecules of 1a lie on crystallographic centers of symmetry, the central Ga—(N—N)2—Ga ring being almost planar as a result of steric interactions between gallium-methyl groups and those on the 'pyrazolyl' rings. The mean Ga—N and Ga—C distances are 1.993 Å and 1.962 Å respectively. Compound 1b was formed by the attack of moisture on the strained dimer 1a. The central feature is a five-membered Ga2N2O ring, with two 3,5-dimethylpyrazoie molecules hydrogen-bonded to it (N—H … O, O—H … N, 2.851 and 2.892 Å) and to each other (N—H … N, 2.907 Å). The five-membered ring adopts a slightly distorted envelope conformation, the angle between the Ga2N2 and N2O moieties being 13.9°. The mean Ga—N and Ga—O distances are 1.989 and 1.934 Å respectively.

Structural studies of organoboron compounds. XII. Crystal and molecular structures of (acetylacetonato)diphenylboron and (tropolonato)diphenylboron

1982 ◽  
Vol 60 (23) ◽  
pp. 2957-2964 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Chelate Ring ◽  
Direct Methods ◽  
Molecular Structures ◽  
Structural Studies ◽  
Organoboron Compounds ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
The Mean

There are two crystalline modifications of (acetylacetonato)diphenylboron: triclinic, a = 8.3557(8), b = 9.3519(8), c = 9.6103(9) Å, α = 96.094(5), β = 94.904(6), γ = 93.489(6)°, Z = 2, space group [Formula: see text], and monoclinic, a = 11.6329(11), b = 17.1628, c = 7.6542(6) Å, β = 97.669(4)°, Z = 4, space group P21/c. Crystals of (tropolonato)diphenylboron are monoclinic, a = 12.1596(5), b = 10.2614(4), c = 12.4883(6) Å, β = 100.965(2)°, Z = 4, space group P21/c. All three structures were solved by direct methods and were refined by full-matrix least-squares procedures to R values of 0.046, 0.041, and 0.035 for 2465, 2124, and 1722 reflections with I ≥ 3σ(I) respectively. Each structure consists of discrete molecules containing tetrahedrally coordinated boron atoms, both the acetylacetonato and tropolonato moieties being delocalized and symmetric. The chelate rings in both forms of (acetylacetonato)-diphenylboron have distorted B-envelope conformations while the chelate ring in (tropolonato)diphenylboron is essentially planar. The mean B—O and B—C distances (corrected for libration) are: 1.543(4) and 1.605(4) Å in triclinic, 1.533(3) and 1.607(4) Å in monoclinic (acetylacetonato)diphenylboron, and 1.555(11) and 1.605(6) Å in (tropolonato)diphenylboron.

Refinement of the Crystal Structure of the Low-quartz Modification of Ferric Phosphate

1975 ◽  
Vol 53 (14) ◽  
pp. 2064-2067 ◽  
Author(s):  
Hok Nam Ng ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Room Temperature ◽  
Unit Cell ◽  
Full Matrix ◽  
Space Group ◽  
Ferric Phosphate ◽  
R Value

The structure of ferric phosphate at room temperature was refined on a Dauphiné-twinned crystal using full-matrix least-squares methods. The final R value was 0.078 for 487 symmetry-independent reflections whose intensities were corrected for twinning. The structure was found to be isotypic with AlPO4 (berlinite) with the space group P3121 and four formula units in a unit cell defined by a = 5.036(2) and c = 11.255(4) Å. The structure is also closely related to that of α-quartz with a nearly doubled c-axis because of the ordering of Fe and P atoms. The PO4 tetrahedron is almost regular with a mean P—O distance of 1.526 Å. The Fe3+ ion is tetrahedrally coordinated with an average Fe—O distance of 1.853 Å.

Structural studies of organoboron compounds. XVIII. Crystal and molecular structures of 2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan and 4-cyclohexyl-6-methyl-2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan

1983 ◽  
Vol 61 (11) ◽  
pp. 2493-2499 ◽  
Author(s):  
W. Kliegel ◽  
D. Nanninga ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Least Squares ◽  
Direct Methods ◽  
Coordination Complexes ◽  
Molecular Structures ◽  
Structural Studies ◽  
Full Matrix ◽  
Space Group ◽  
Crystal And Molecular Structures ◽  
Anionic Ligand ◽  
Oxide Crystals

The crystal structures of 2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan, 6a, and 4-cyclohexyl-6-methyl-2,2-diphenyl-1,3-dioxa-3a-azonia-2-borataindan, 6b, reported here represent the first crystallographic examples of coordination complexes of the anionic ligand derived from 2-hydroxypyridine N-oxide. Crystals of 6a are monoclinic, a = 11.5210(13), b = 10.2860(8), c = 12.7354(15) Å, β = 101.878(5)°, Z = 4, space group P21/c; and those of 6b are monoclinic, a = 8.5047(8), b = 15.6603(14), c = 16.0501(18) Å, β = 104.776(5)°, Z = 4, space group P21/n. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.039 and 0.042 for 1440 and 1750 reflections with I ≥ 3σ(I), respectively. Both molecules feature tetrahedrally coordinated boron atoms incorporated into five-membered OBOCN chelate rings which have B-envelope conformations. The observed molecular geometries indicate that the ligand may be classed as a hybrid of the 2-hydroxypyridine N-oxide and 1-hydroxy-2-pyridinone tautomers of the parent alcohol. Important bond lengths (corrected for libration) are: O—B = 1.557(3)−1.580(3), mean C—B = 1.600(4), C—O = 1.316(3), and N—O = 1.389(3) Å.

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