ELECTRON INDUCTIVE PERTURBATION(S) OF HETERONUCLEAR METAL-METAL BONDS- ISOCYANIDE AND INDENYL DERIVATIVES OF THE MIXED-METAL DIMERS [(ETA(5)-C5H5)FE(CO)(2)RE(CO)(5)] AND [MNRE(CO)(10)]
Pd. Harvey et al., ELECTRON INDUCTIVE PERTURBATION(S) OF HETERONUCLEAR METAL-METAL BONDS- ISOCYANIDE AND INDENYL DERIVATIVES OF THE MIXED-METAL DIMERS [(ETA(5)-C5H5)FE(CO)(2)RE(CO)(5)] AND [MNRE(CO)(10)], Canadian journal of chemistry, 72(10), 1994, pp. 2176-2182
The properties of the heteronuclear metal-metal bonds in the unbridged
[eta(5)-C5H5)Fe(Co)(2)Re(CO)(5-n)(CNR)(n)] and [(eta(5)-C9H7)Fe(CO)(2
)Re(CO)(5-n)(CNR)(n)] complexes (n = 0, 1, 2; R = tert-butyl (tBu) and
2,6-dimethylphenyl (Xy)) and the two equa torially substituted isomer
s of [MnRe(CO)(8)(CN-tBu)(2)] have been investigated theoretically by
Extended Huckel Molecular Orbital calculations (EHMO) and experimental
ly by UV-visible spectroscopy, electrochemistry, and by microRaman or
FT-Raman spectroscopy. The expected d sigma orbital is the lowest uno
ccupied molecular orbital (LUMO), mainly fabricated by interactions of
the metal d(z2) orbital, but the d pi and d sigma orbitals are the h
ighest occupied molecular orbital (HOMO) and HOMO-1, respectively, as
demonstrated experimentally from the UV-visible spectra. The EHMO comp
utations demonstrate the mixing between these two d pi (and d delta)
and d sigma MO orbitals. The influence of substituent effects on the s
pectroscopic and electrochemical properties is complicated and is inte
rpreted in terms of inductive effects and relative destabilisation of
the d sigma, d pi, and d sigma* molecular orbitals. Finally, the meta
l-metal stretching frequencies for four mixed metal dimers (MnRe and F
eRe) are reported.