Electronic structures of dative metal-metal bonds; Ab initio molecular orbital calculations of (OC)5Os-M(CO)5 (M = tungsten, chromium) in comparison with (OC)5M-M(CO)5 (M = rhenium, manganese)

1992 ◽  
Vol 31 (10) ◽  
pp. 1740-1744 ◽  
Author(s):  
H. Nakatsuji ◽  
M. Hada ◽  
A. Kawashima
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Electronic Structures ◽  
Molecular Orbital Calculations ◽  
Metal Metal ◽  
Metal Metal Bonds ◽  
Metal Bonds

Electron inductive perturbation(s) of heteronuclear metal–metal bonds. Isocyanide and indenyl derivatives of the mixed metal dimers [(η5–C5H5)Fe(CO)2Re(CO)5] and [MnRe(CO)10]

1994 ◽  
Vol 72 (10) ◽  
pp. 2176-2182 ◽  
Author(s):  
Pierre D. Harvey ◽  
Peter Johnston ◽  
Neil J. Coville
Keyword(s):  
Molecular Orbital ◽  
Substituent Effects ◽  
Molecular Orbital Calculations ◽  
Mixed Metal ◽  
Metal Metal ◽  
Ft Raman Spectroscopy ◽  
Lowest Unoccupied Molecular Orbital ◽  
Uv Visible ◽  
Metal Metal Bonds ◽  
Metal Bonds

The properties of the heteronuclear metal–metal bonds in the unbridged [η5–C5H5)Fe(CO)2Re(CO)5−n(CNR)n] and [(η5–C9H7)Fe(CO)2Re(CO)5−n(CNR)n complexes (n = 0, 1, 2; R = tert-butyl (tBu) and 2,6-dimethylphenyl (Xy)) and the two equatorially substituted isomers of [MnRe(CO)8(CN-tBu)2] have been investigated theoretically by Extended Hückel Molecular Orbital calculations (EHMO) and experimentally by UV–visible spectroscopy, electrochemistry, and by microRaman or FT-Raman spectroscopy. The expected dσ* orbital is the lowest unoccupied molecular orbital (LUMO), mainly fabricated by interactions of the metal [Formula: see text] orbital, but the dπ* and dσ orbitals are the highest occupied molecular orbital (HOMO) and HOMO-1, respectively, as demonstrated experimentally from the UV–visible spectra. The EHMO computations demonstrate the mixing between these two dπ* (and dδ) and dσ MO orbitals. The influence of substituent effects on the spectroscopic and electrochemical properties is complicated and is interpreted in terms of inductive effects and relative destabilisation of the dσ, dπ*, and dσ* molecular orbitals. Finally, the metal–metal stretching frequencies for four mixed metal dimers (MnRe and FeRe) are reported.

First-principles investigation on environmental embrittlement of TiAl

1998 ◽  
Vol 13 (2) ◽  
pp. 290-301 ◽  
Author(s):  
Y. Liu ◽  
K. Y. ◽  
J. H. Zhang ◽  
G. Lu ◽  
Z. Q. Hu
Keyword(s):  
Hydrogen Embrittlement ◽  
First Principles ◽  
Electronic Structures ◽  
Bond Order ◽  
Environmental Embrittlement ◽  
Cohesive Properties ◽  
Metal Metal ◽  
Metal Metal Bonds ◽  
Metal Bonds ◽  
Mn Doped

To investigate the hydrogen embrittlement and Mn ductilization effects in TiAl, the electronic structures of pure, H-doped, Mn-doped, and Mn, H-codoped TiAl have been studied by the first-principles discrete variational Xa calculations. Local environmental total bond order (LTBO), which is developed for the description of the cohesive properties in a local atom environment involving impurities, should be regarded as a new microscopic criterion for embrittlement. The larger LTBO presents the stronger cohesion and the better ductility of the system. Our results show that H obviously decreases LTBO while Mn increases it, which suggests H as an embrittler while Mn as a ductilizer. It is of key importance to understand hydrogen embrittlement in which hydrogen causes the weakening of its surrounding metal-metal bonds.

Interatomic Potentials for Metal/Metal Wetting Systems

2005 ◽  
Vol 502 ◽  
pp. 75-80 ◽  
Author(s):  
Takehiko Makino ◽  
Atsushi Kubo ◽  
Hiroki Iida ◽  
Shun Ichiro Tanaka
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Physical Meaning ◽  
Surface Alloy ◽  
Molecular Orbital Calculations ◽  
Interatomic Potentials ◽  
Solid Interface ◽  
Metal Metal ◽  
Surface Liquid ◽  
Three Components

Considering the uniqueness of wetting systems consisting of three components, namely, the surface, liquid and liquid/solid interface, it is desirable to construct interatomic potentials following a consistent policy. To investigate the physical meaning of the behavior in terms of the interatomic potentials, the wetting systems are modeled by simple two-body interatomic potentials derived using ab initio molecular orbital calculations for hypothetical clusters representing the above three components. For In and Sn liquid atoms, spreading occurs on a Cu (111) surface, while in contrast, liquid atoms penetrate the substrate and form a surface alloy in the case of a Pd (111) surface.

One-dimensional complexes extended by unbridged metal–metal bonds based on a HOMO–LUMO interaction at the dz2orbital between platinum and heterometal atoms

2017 ◽  
Vol 46 (17) ◽  
pp. 5474-5492 ◽  
Author(s):  
Kazuhiro Uemura
Keyword(s):  
Electronic Structures ◽  
Dimensional Chain ◽  
One Dimensional ◽  
Chain Complexes ◽  
Metal Metal ◽  
Metal Metal Bonds ◽  
Metal Bonds ◽  
Homo Lumo

Crystal and electronic structures of seventeen heterometallic one-dimensional chain complexes are reviewed and discussed.

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