Ligand metal charge-transfer

The electronic spectra of these materials recorded in chloroform solution appear to be dominated by intense bands originating from internal ligand transitions, metal-ligand and ligand-metal charge-transfer bands, whose intensities change markedly with changes in the population of the two spin states [7]. 

The u.v.-visible spectra of [Pt2X6]2- (X = Cl or Br) have been measured 14 the band assignments include ligand- metal charge-transfer and d— p bands, in addition to the low-intensity d- -d bands. The purple vapour complex formed from [Pt6Cl12] solid cluster and gaseous A1C13 has been studied spectrophotometrically.120... 

There are many other Prussian blue analogs for which the visible spectrum is complex and not understood. Heavy metal ferricyanides and hexacyano complexes of other transition metals with less than d configurations are in this class due to the presence of ligand-metal charge transfer processes. 

The chelation effect of Cys-X-Y-Cys was also found for the MCD spectra of Fe(III) complexes of Z-Cys-Pro-Leu-Cys-OMe or Z-Cys-Ala-Ala-Cys-OMe, which exhibited a characteristic ligand-metal charge transfer (LMCT) at 350 nm, but not for those of the Fe(III) complex of Z-Ala-Cys-OMe, Z-Cys-Ala-Cys-OMe, or S2-o-xyl (28). The MCD spectral differences in the region of 300-400 nm are related to the difference in the electronic states of the Fe(III) singly occupied metal t2 orbitals affected by the lone pair on the sulfur atom. The possibility of a spectroscopic splitting by a specific Cys-thiolate orientation relative to other Fe-S bondings has been predicted theoretically by Bair and Goddard (29). The orientation of n orbitals of the sulfur lone pair is now found to be determined by the peptide conformation which dictates the steric disposition of the S-C bond. 

Platinum(IV) is an oxidant therefore, ligand-metal charge-transfer (LMCT) transitions are prominent in the electronic spectra of its complexes and play important roles in the photosubstitution chemistry. This is especially true for the hexahalo complexes, [PtXj]. The aqueous hexachloroplatinate(IV) ion, [PtCl ] , undergoes both photoaquation ... 

Platinum(IV) is an oxidant therefore, ligand-metal charge-transfer (LMCT) tran-... 

---