Synthese und Molekülgeometrie von Dichloro[η2-bis(di-r-butylphosphino)methan]pIatin(II), Pt(dtbpm)Cl2. Die Elektronenstruktur von 1,3-Diphosphaplatinacyclobutan-Fragmenten / Synthesis and Molecular Structure of Dichloro[η2-bis(di-t-butylphosphino)methane]platinum(II), Pt(dtbpm)Cl2. The Electronic Structure of 1,3-Diphosphaplatinacyclobutane Fragments

1987 ◽  
Vol 42 (4) ◽  
pp. 395-409 ◽  
Author(s):  
Peter Hofmann ◽  
Helmut Heiß ◽  
Gerhard Müller
Keyword(s):  
Molecular Structure ◽  
Electronic Structure ◽  
Crystal And Molecular Structure ◽  
Cone Angle ◽  
Membered Ring ◽  
Experimental Investigations ◽  
Molecular Orbital Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potential Precursor

Based upon the experimentally known but yet unexplained very different reactivities of the two isoelectronic and isolobal intermediates Pt(PMe3)2 and Pt(PEt3)2, the electronic structure and bonding capability of such 14 electron fragments as a function of their geometry (P-Pt-P angle α, determined by the phosphane cone angle) are investigated using molecular orbital calculations. A decrease of the P-Pt -P angle leads to an exceptionally pronounced energy ascent of the b2-HOMO of Pt(PR3)2 species, which, as a consequence, might lead to unusual reactivity patterns and bonding capabilities of 1,3-diphosphaplatinacyclobutane fragments, for which an extreme electronic situation is enforced by steric constraints. Dichloro[η2-bis(di-r-butylphosphino) methane]platinum(II), Pt(dtbpm)Cl2, is synthesized as a potential precursor of Pt(dtbpm), in order to allow experimental investigations of this taylor made four-membered ring chelate complex of Pt(0). The crystal and molecular structure of Pt(dtbpm)Cl2 · 2 CHCl3 has been determined by X-ray diffraction.

The preparation and the crystal and molecular structure of S3N2NH2+BF4−; a molecular orbital study of the protonation of the trisulphur trinitride anion

1984 ◽  
Vol 62 (9) ◽  
pp. 1822-1827 ◽  
Author(s):  
Clifford G. Marcellus ◽  
Richard T. Oakley ◽  
A. Wallace Cordes ◽  
William T. Pennington
Keyword(s):  
Molecular Structure ◽  
Molecular Orbital ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Membered Ring ◽  
Molecular Orbital Calculations ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Molecular Orbital Study

Protonation of the trisulphur trinitride ion, S3N3−, with tetrafluoroboric acid yields the ring-contracted S-amino thiodithiazyl salt, S3N2NH2+BF4−. The crystal and molecular structure of this salt has been determined by X-ray diffraction. The crystals are triclinic, space group P1, with a = 5.445(2), b = 7.346(3), c = 9.473(5) Å, α = 85.89(4), β = 83.92(3), γ = 82.13(3)°, V = 372.6(4) Å3, Dc = 2.02 g cm−3, and Z = 2. The structure was solved by direct methods and refined by full-matrix least-squares procedures to give a final R = 0.060. The structure of the five-membered ring with a single exocyclic NH2 group bonded to sulphur is discussed in relation to other S3N2NR derivatives. The reasons for the instability of six-membered rings of the type S3N3R are discussed in the light of MNDO molecular orbital calculations on an S3N3H model.

The crystal and molecular structure of tetrabenzocyclodecan-1,6-dione

1980 ◽  
Vol 58 (8) ◽  
pp. 777-779 ◽  
Author(s):  
T. Stanley Cameron ◽  
Christine Chan ◽  
David G. Morris ◽  
Alistair G. Shepherd
Keyword(s):  
Molecular Structure ◽  
Diffraction Analysis ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Nmr Spectrum ◽  
X Ray ◽  
C Nmr

The crystals belong to the orthorhombic space group C222, with a = 9.226, b = 12.092, c = 16.513 Å, Z = 4. A single crystal X-ray diffraction analysis has shown that the title compound, in which all carbon atoms are sp2 hybridized, exists with the ten membered ring in a slightly twisted tub conformation. The 13C nmr spectrum is also reported.

Molekül-und Elektronenstruktur des Thioheteroanions [S2 WS2CoS2WS2]2- / Molecular and Electronic Structure of the Thiohetero Anion [S2WS2CoS2WS2]2-

1978 ◽  
Vol 33 (9) ◽  
pp. 978-982 ◽  
Author(s):  
A. Müller ◽  
N. Mohan ◽  
H. Bögge
Keyword(s):  
Molecular Structure ◽  
Electronic Structure ◽  
Single Crystal ◽  
Diffraction Data ◽  
Complex Anion ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Data Space ◽  
Molecular And Electronic Structure

Abstract The crystal and molecular structure of [(C6H5)4P]2[Co(WS4)2] was determined from single crystal X-ray diffraction data (space group P21/c with a = 18.542(4), b = 15.443(2), c= 18.713(2) Å, β= 108.73(1)°, Z = 4). In the complex anion Co is coordinated by two bidentate chelating WS42- anions, with a nearly tetrahedral surrounding of Co. The bond lengths in the planar metal sulfur ring CoS2W are Co-S = 2.26 Å and W-S = 2.22 Å, while the terminal W-S bonds are 2.14 Å.

Crystal structures of medium ring compounds. Part III. The crystal and molecular structure of trans-anti-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane

1979 ◽  
Vol 57 (16) ◽  
pp. 2154-2158 ◽  
Author(s):  
Aris Terzis ◽  
T. Bruce Grindley
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Chair Conformation ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ring Compounds ◽  
R Value ◽  
Medium Ring

The crystal structure of trans-anti-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane (3) has been determined by X-ray diffraction. The crystals are monoclinic, a = 11.919(3), b = 17.330(7), c = 7.019(2) Å, β = 98.91(1)°, P21/c, with Z = 4. The structure was solved by application of the tangent formula and refined by large block least squares to a final R value of 0.060 (Rw = 0.058).The ten-membered ring is present in the crystal in a twist-chair-boat-chair conformation — one which has been calculated to be relatively unstable for cyclodecane. Possible reasons why 3 adopts this conformation are discussed.

The conformation of a ten-membered ring: the crystal and molecular structure of trans-syn-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane

1977 ◽  
Vol 55 (14) ◽  
pp. 2692-2699 ◽  
Author(s):  
Aris Terzis ◽  
T. Bruce Grindley ◽  
J. Brian Faught
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Membered Ring ◽  
Thermal Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

The crystal structure of trans-sys-trans-4,5:9,10-biscyclohexano-1,3,6,8-tetraoxecane (1) has been determined by X-ray diffraction. The crystals are monoclinic, a = 10.995(2), b = 5.291(1), c = 12.241(2) Å, β = 114.68(1)°, P21/c, with Z = 2. The structure was solved by the application of symbolic addition procedures and refined with anisotropic thermal parameters for all atoms to a final R value of 0.039 (Rw 0.062) for 1135 independent reflections.The ten-membered tetraoxecane ring is present in the crystal in a boat-chair-boat (BCB) conformation, which is somewhat different in geometry than the BCB conformations observed for cyclodecane derivatives. The causes of these differences are discussed. Intramolecular non-bonded interactions cause one CH2 group to be significantly distorted from local C2v symmetry.

The crystal and molecular structure of syn-[4.4.3]propella-2,4,12-trien-11-ol 3,5-dinitrobenzoate

1985 ◽  
Vol 63 (4) ◽  
pp. 862-865 ◽  
Author(s):  
Judith C. Gallucci ◽  
Katsuo Ohkata ◽  
Leo A. Paquette
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Molecular Geometry ◽  
Chair Conformation ◽  
Membered Ring ◽  
Aqueous Acetone ◽  
X Ray Diffraction ◽  
X Ray ◽  
R Value

The crystal structure of syn-[4.4.3]propella-2,4,12-trien-11-ol 3,5-dinitrobenzoate, 2, has been determined by single crystal X-ray diffraction and refined to an R value of 0.051. The crystal structure is triclinic with a = 10.208(2), b = 13.355(2), c = 7.068(1) Å, α = 99.35(1)°, β = 100.63(1)°, γ = 100.79(1)°, and the space group is [Formula: see text] with two molecules per cell, D(calcd) = 1.39 g cm−3. The unsaturated five-membered ring resides in an envelope conformation with C6—C11—C12—C13 lying essentially in a plane. The fifth atom, C1, is positioned 0.47 Å out of this plane on the side opposite O1. The latter is situated 1.38 Å away and projects the 3,5-dinitrobenzoate group above the central portion of the cyclohexadiene unit. Four contiguous carbon atoms in the latter ring are mutually coplanar and the fused cyclohexane ring adopts a chair conformation. The overall molecular geometry is reconcilable with its solvolytic behavior in aqueous acetone.

Crystal and molecular structure of a natural vanadyl porphyrin

1984 ◽  
Vol 37 (4) ◽  
pp. 761 ◽  
Author(s):  
SA Miller ◽  
TW Hambley ◽  
JC Taylor
Keyword(s):  
Molecular Structure ◽  
Oil Shale ◽  
Crystal And Molecular Structure ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
X Ray ◽  
A Cell ◽  
Planar Molecules ◽  
Solvent Molecules

The crystal and molecular structure of a vanadyl deoxophylloerythroetioporphyrin (dpep) extracted from oil shale has been determined by single crystal X-ray diffraction. The compound crystallizes in space group P21/c of the monoclinic system with four formula units in a cell of dimensions a 12.912(3), b 14.151(4), c 18.404(8) �, β 70.34(2)�. Block matrix least-squares refinement gives a final R index of 0.077 for 2296 reflections. The planar molecules are packed almost parallel, with the chloroform solvent molecules lying between the planes and weakly associated with the vanadyl oxygen. The molecular structure establishes the presence of an isocyclic five-membered ring, which suggests that the molecule is a derivative of chlorophyll.

Crystal and molecular structure of diorganoammonium oxalatotrimethylstannate, [R2NH2][Me3Sn(C2O4)] (R=i-Bu, cyclohexyl)

2011 ◽  
Vol 34 (5-6) ◽  
pp. 127-130 ◽  
Author(s):  
Yaya Sow ◽  
Libasse Diop ◽  
Kieran C. Molloy ◽  
Gabrielle Kociok-Köhn
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonds ◽  
Diffraction Study ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Trans Complex ◽  
A Chain ◽  
Distorted Trigonal Bipyramidal

Abstract The title compounds [R2NH2][C2O4SnMe3](R=i-Bu, Cy), in which tin atoms adopt a distorted trigonal bipyramidal configuration, have been prepared and submitted to an X-ray diffraction study. These compounds have been obtained from the reaction of (Cy2NH2)2C2O4·H2O or (i-Bu2NH2)2C2O4 with SnMe3Cl. In both [R2NH2][C2O4SnMe3] compounds, the trans complex has an almost regular trigonal bipyramidal geometry around the tin atom. The SnMe3 residues are connected as a chain with bridging oxalate anions in a trans-SnC3O2 framework, the oxygen atoms being in axial positions. The cations connect linear adjacent chains through NH…O hydrogen bonds giving layered structures.

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