ChemInform Abstract: STERIC STRAIN IN COBALT(III) COMPOUNDS. CRYSTAL AND MOLECULAR STRUCTURE OF DIBENZOYLMETHANATO-O,O′-(N,N′-O-PHENYLENEBIS(SALICYLIDENEIMINATO))COBALT(III)

1976 ◽  
Vol 7 (14) ◽  
pp. no-no
Author(s):  
DIANE CUMMINS ◽  
E. DONALD MCKENZIE ◽  
HARRY MILBURN
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Steric Strain

Crystal and Molecular Structure of the Minor Cyclo-Dimerization Product of 8,8-Dimethylisobenzofulvene

1979 ◽  
Vol 32 (1) ◽  
pp. 211 ◽  
Author(s):  
BM Gatehouse ◽  
P Leverett ◽  
D Taylor
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Steric Strain ◽  
Orthorhombic Space Group ◽  
Full Matrix ◽  
Theoretical Predictions ◽  
Dimerization Product ◽  
Single Bonds ◽  
Dimerization Process

8,8-Dimethylisobenzofulvene undergoes spontaneous cyclo-dimerization to give a mixture of two isomers of composition C24H24, The minor isomer crystallizes in the orthorhombic space group Pbca with a 16.815(8), b 16.975(8) and c 13.058(6)� pobs 1.13(3)g cm-3, pealc 1.13 g cm-3 for Z 8. The structure was solved from diffractometer data by direct methods and was refined by full-matrix least squares to final residuals R 0.040, Rw 0.046 for 885 observed data. The stereochemistry of the minor dimer is established, contrary to theoretical predictions, as the exo-isomer. There is evidence of intramolecular steric strain particularly demonstrated by the elongated C-C single bonds, 1.590(7) and 1.570(7) �, which are formed in the dimerization process.

Crystal and molecular structure of (RS,RS)-Tetraammine(4,5-dihydroxy-4,5-dimethyl-1-pyrroline-2-carboxylato)cobalt(III) perchlorate

1975 ◽  
Vol 28 (10) ◽  
pp. 2129 ◽  
Author(s):  
GB Robertson ◽  
PO Whimp
Keyword(s):  
Molecular Structure ◽  
Hydrogen Atom ◽  
Crystal And Molecular Structure ◽  
Three Dimensional ◽  
Methyl Groups ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Steric Strain ◽  
X Ray ◽  
R Factors

The structure of a cobalt(III) tetraammine complex of 4,5-dihydroxy- 4,5-dimethyl-1-pyrroline-2-carboxylic acid (abbreviated as hmpc), (RS,RS)-[Co(NH3)4(hmpc)] (ClO4)2,H2O, has been determined from three- dimensional X-ray data collected by counter methods. Crystals are monoclinic, space group P21/c, with a 11.984(5), b 8.836(4), c 19.609(7) Ǻ, β 110.58(2)�, Z 4. The structure has been refined to weighted and unweighted R-factors of 0.068 and 0.063, respectively, for the 1616 independent reflections with I/σ(I) ≥ 3.0. Hydrogen atoms could not be located and have not been included in the scattering model. There is considerable steric strain within the substituted pyrroline ligand, and the C=N distance is 1.293(8) Ǻ. Surprisingly, the methyl groups in the 4- and 5-positions are in a cisoid configuration (the torsion angle for the methyl groups about the 4-5 bond is 39.5�), and consequently the hydroxyl oxygen atoms are close [O-O distance, 2.583(8) Ǻ]; this suggests that there may be a bridging hydrogen atom.

Crystal and molecular structure of a platinum(II) complex with β-mercaptoethylamine hydrochloride

2018 ◽  
Vol 59 (1) ◽  
pp. 191-195
Author(s):  
A. N. Azizova ◽  
◽  
D. B. Tagiev ◽  
S. N. Osmanova ◽  
Sh. G. Kasumov ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure

The crystal and molecular structure of tris(pentamethylenedithiocarbamate) chromium(III)-chloroform (1 : 2)

1981 ◽  
Vol 46 (1) ◽  
pp. 6-19 ◽  
Author(s):  
Viktor Kettman ◽  
Ján Garaj ◽  
Jaroslav Majer
Keyword(s):  
Molecular Structure ◽  
Structural Analysis ◽  
Crystal And Molecular Structure ◽  
Analysis Method ◽  
Complex Molecules ◽  
Coordination Polyhedra ◽  
X Ray ◽  
Cell Dimensions ◽  
Crustal Density ◽  
Unit Cell Dimensions

The crystal and molecular structure of [Cr(S2CN(CH2)5)3].2 CHCl3 was found by the X-ray structural analysis method. The value R 0.090 was found for 1 131 observed independent reflections. The substance crystallizes in a space group of symmetry P212121 with the following unit cell dimensions: a = 0.8675 (6), b = 1.815(2), c = 2.155(3) nm. The experimentally observed crustal density was 1.48 Mgm-3 and the value calculated for Z = 4 was 1.51 Mgm-3. The CrS6 coordination polyhedron has the shape of a trigonally distorted octahedron, where the D3 symmetry is a approximately retained. The degree of trigonal distortion expressed as the projection of the chelate S-Cr-S angle onto the plane perpendicular to the C3 pseudo axis is Φ = 41.7° (Φ = 60° for an octahedron). The skeleton of the structure formed by the complex molecules contains channels filled with chloroform molecules. The specific type of complex-chloroform interaction consists of the formation of hydrogen bonds of the chloroform protons with the fully occupied pπ-orbitals of the sulphur atoms in the coordination polyhedra. The low stability and crystal decomposition can be explained by loss of chloroform from the channels.

The Crystal and Molecular Structure of sym-fac-(1,4,7-Triazaheptane)-(S)-aspartatocobalt(III) Diperchlorate Dihydrate

1994 ◽  
Vol 59 (5) ◽  
pp. 1052-1058 ◽  
Author(s):  
Jan Ondráček ◽  
Jana Ondráčková ◽  
Jaroslav Maixner ◽  
František Jursík
Keyword(s):  
Molecular Structure ◽  
Aspartic Acid ◽  
Crystal And Molecular Structure ◽  
Heavy Atom ◽  
Membered Ring ◽  
Boat Conformation ◽  
Hydrogen Atoms ◽  
Orthorhombic System ◽  
Anisotropic Temperature ◽  
Heavy Atom Method

The crystal and molecular structure of s-fac-[Co((S)-Asp)(dien)]ClO4 . HClO4 .2 H2O (dien = 1,4,7-triazaheptane) was solved by the heavy atom method. The position parameters of the non-hydrogen atoms and their anisotropic temperature parameters were refined based on 1 726 observed reflections with a final value of R = 0.073. The substance crystallizes in the orthorhombic system in the space group P212121, Z = 4, a = 8.506(1), b = 17.171(2), c = 13.277(1) Å. The structure involves hydrogen bonds between the O2, O4 and HN2 atoms of aspartic acid and the two molecules of water. The five-membered dien chelate rings take the asymmetric envelope conformations. The five-membered ring of (S)-aspartic acid possesses the symmetric envelope conformation whereas the six-membered ring exhibits the skew boat conformation.

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