Valence Bond Concepts Applied to the Molecular Mechanics Description of Molecular Shapes. 3. Applications to Transition Metal Alkyls and Hydrides

1998 ◽  
Vol 120 (11) ◽  
pp. 2641-2649 ◽  
Author(s):  
Clark R. Landis ◽  
Thomas Cleveland ◽  
Timothy K. Firman
Keyword(s):  
Transition Metal ◽  
Molecular Mechanics ◽  
Valence Bond ◽  
Metal Alkyls

Symmetry Violations in Partially Oxidized One-Dimensional (1D)Transition Metal Polymers. Metal-Ligand-Metal(M-L-M) Bridged Systems

1984 ◽  
Vol 39 (9) ◽  
pp. 807-829
Author(s):  
Michael C. Böhm
Keyword(s):  
Transition Metal ◽  
Density Wave ◽  
Tight Binding ◽  
Mean Field ◽  
Valence Bond ◽  
Hole State ◽  
One Dimensional ◽  
Metal Derivatives ◽  
A Charge ◽  
Metal Ligand

The band structure of the metal-ligand-metal (M-L-M) bridged quasi one-dimensional (1D) cyclopentadienylmanganese polymer, MnCp 1, has been studied in the unoxidized state and in a partly oxidized modification with one electron removed from each second MnCp fragment. The tight-binding approach is based on a semiempirical self-consistent-field (SCF) Hartree-Fock (HF) crystal orbital (CO) model of the INDO-type (intermediate neglect of differential overlap) combined with a statistical averaging procedure which has its origin in the grand canonical ensemble. The latter approximation allows for an efficient investigation of violations of the translation symmetries in the oxidized 1D material. The oxidation process in 1 is both ligand- and metal-centered (Mn 3d-2 states). The mean-field minimum corresponds to a charge density wave (CDW) solution with inequivalent Mn sites within the employed repeat-units. The symmetry adapted solution with electronically identical 3d centers is a maximum in the variational space. The coupling of this electronic instability to geometrical deformations is also analyzed. The ligand amplitudes encountered in the hole-state wave function prevent extremely large charge separations between the 3d centers which are found in ID systems without bridging moieties (e.g. Ni(CN)2-5 chain). The symmetry reduction in oxidized 1 is compared with violations of spatial symmetries in finite transition metal derivatives and simple solids. The stabilization of the valence bond-type (VB) solution is physically rationalized (i.e. left-right correlations between the 3d centers). The computational results derived for 1 are generalized to oxidized transition metal chains with band occupancies that are simple fractions of the number of stacking units and to 1D systems that deviate from this relation. The entropy-influence for temperatures T ≠ 0 is shortly discussed (stabilization of domain or cluster structures).

A Valence Bond Perspective on the Molecular Shapes of Simple Metal Alkyls and Hydrides

1998 ◽  
Vol 120 (8) ◽  
pp. 1842-1854 ◽  
Author(s):  
Clark R. Landis ◽  
Timothy K. Firman ◽  
Daniel M. Root ◽  
Thomas Cleveland
Keyword(s):  
Valence Bond ◽  
Simple Metal ◽  
Metal Alkyls

ChemInform Abstract: PHOTOELECTRON SPECTRA OF SOME TRANSITION METAL ALKYLS AND OXOALKYLS

1978 ◽  
Vol 9 (52) ◽  
Author(s):  
J. C. GREEN ◽  
D. R. LLOYD ◽  
L. GALYER ◽  
K. MERTIS ◽  
G. WILKINSON
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectra ◽  
Metal Alkyls

Photoelectron spectra of some transition metal alkyls and oxoalkyls

1978 ◽  
pp. 1403 ◽  
Author(s):  
Jennifer C. Green ◽  
D. Robert Lloyd ◽  
Lee Galyer ◽  
Konstantinos Mertis ◽  
Geoffrey Wilkinson
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectra ◽  
Metal Alkyls

Some critical issues in the application of quantum mechanics/molecular mechanics methods to the study of transition metal complexes

2003 ◽  
Vol 124 ◽  
pp. 429-441 ◽  
Author(s):  
David Balcells ◽  
Galí Drudis-Solé ◽  
Maria Besora ◽  
Nicole Dölker ◽  
Gregori Ujaque ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Transition Metal ◽  
Metal Complexes ◽  
Molecular Mechanics ◽  
Transition Metal Complexes ◽  
Critical Issues
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