Evidence for twisted norbornanes. X-ray diffraction and valence force-field calculations

1970 ◽  
Vol 92 (7) ◽  
pp. 1995-1999 ◽  
Author(s):  
C. Altona ◽  
Muttaiya. Sundaralingam
Keyword(s):  
Force Field ◽  
X Ray Diffraction ◽  
Force Field Calculations ◽  
Valence Force ◽  
X Ray ◽  
Valence Force Field

Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von cis-[ReCl4X2]2-, X = NCS, NCSe / Crystal Structures, Vibrational Spectra and Normal Coordinate Analysis of cis-[ReCl4X2]2-, X = NCS, NCSe

1998 ◽  
Vol 53 (11) ◽  
pp. 1329-1334 ◽  
Author(s):  
L. Homolya ◽  
S. Strueß ◽  
W. Preetz
Keyword(s):  
Crystal Structures ◽  
Normal Coordinate Analysis ◽  
X Ray Diffraction ◽  
Normal Coordinate ◽  
Triclinic Space Group ◽  
Valence Force ◽  
Space Group ◽  
X Ray ◽  
Valence Force Field ◽  
Ir And Raman

The crystal structures of cis-(n-Bu4N)2[ReCl4(NCS)2] (triclinic, space group P1̅, a = 11,245( 1), b = 20.174(3), c = 21.320(8) Å, a =109.06(2), β = 96.46(2), γ = 98.22(5)°, Z = 4) and cis-(Ph4P)2[ReCl4(NCSe)2]·2CH2Cl2 (triclinic, space group P1̅, a = 10.341(2), b = 13.436(3), c = 19.616(4) Å, α = 92.70(2), β = 92.02(2), γ = 89.99( 1)°, Z= 2) have been determined by single crystal X-ray diffraction analysis. Both ambidentate ligands NCS and NCSe are bonded via the N atom. Using the molecular parameters of the X-ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu4N) salts have been assigned by normal coordinate analysis based on a modified valence force field. The valence force constants fd(ReN) are 1,78(NCS) and 1,79(NCSe) mdyn/ Å.

scholarly journals Vibrational Assignments of Acetyliodide and Deuterated Species, Based on Infrared Gas Spectra and Valence Force Field Calculations.

1984 ◽  
Vol 38a ◽  
pp. 453-466 ◽  
Author(s):  
Flemming M. Nicolaisen ◽  
J. Stokkebro Hansen ◽  
Staffan Castensson ◽  
Masunobu Maeda ◽  
Hitoshi Ohtaki
Keyword(s):  
Force Field ◽  
Force Field Calculations ◽  
Valence Force ◽  
Vibrational Assignments ◽  
Valence Force Field

Molecular Modelling: Ein Beitrag zum Verständnis der katalytischen enantioselektiven Hydrovinylierung von Styrol / Molecular Modelling: A Contribution to the Understanding of the Catalytic Enantioselective Hydrovinylation of Styrene

1995 ◽  
Vol 50 (4) ◽  
pp. 488-502 ◽  
Author(s):  
Klaus Angermund ◽  
Anette Eckerle ◽  
Frank Lutz
Keyword(s):  
Force Field ◽  
Molecular Modelling ◽  
Catalytic Properties ◽  
Industrial Applications ◽  
High Reactivity ◽  
Valence Force ◽  
X Ray ◽  
Valence Force Field ◽  
Derivatives Of ◽  
Good Agreement

The hydrovinylation of styrene can be catalyzed by the addition of phosphane-modified Ni(II) compounds with high reactivity and enantioselectivity if the azaphospholene 1 is used as P-component of the catalysts. Until recently the industrial applications of 1 have been hampered by its difficult synthesis. To search for easier to synthesize, but equally well catalyzing derivatives of 1 a molecular modelling study was carried out. Based on already experimentally tested and structurally characterized azaphospholenes a model is developed, which not only leads to a better understanding of the catalytic process and but also to a relatively easy way to predict catalytic properties in these systems. Using an extended, customized valence force field several new derivatives of 1 have been tested. Their predicted and experimentally determined catalytic properties are in good agreement. The X-ray structures of the phenyl-substituted, monomeric azaphospholene 13, which hitherto results in the second best catalyst, and of its precursor 19 are presented.

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