Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1231953 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2011 | 9 Pages |
Abstract
The electronic spectra of triple-stranded complexes of Ti(IV) with bis(benzene-o-dithiolato) ligands (H4-L1Â =Â 1,2-bis(2,3-dimercaptobenzamido)ethane; H4-L2Â =Â 1,2-bis(2,3-dimercaptobenzamido)benzene) were investigated at the TD-DFT level of theory employing B3LYP/LANL2DZ. The influence of the nature (aliphatic or aromatic) of the spacer bridging both {Ti(S2C6H3)3} units on the absorptive features of the dinuclear complexes was also studied. B3LYP/LANL2DZ leads to spectra accounting for four absorption bands. At the lowest-energy region, the most important transitions are due to ligand-to-metal charge transfer (LMCT), in which out-of-plane ligand-centered orbitals and titanium-based MOs are involved. In going to the blue-region, a third band was detected with excitations showing an important contribution from ligand-to-ligand charge transfer (LLCT) and indeed, a combined LMCTÂ +Â LLCT character has been considered. This observation seems to arise from a decrease in the metallic character of the LUMO-derivatives involved in the excitations. The origin of the absorption band at the highest-energy part of the spectrum is assigned to a LLCT. The influence of the nature of the spacer on the molar absorption coefficients (É) for this band has been clearly observed. The complex bearing aliphatic spacer shows É of about 5 E+4Â Mâ1Â cmâ1, while the one containing an aromatic spacer present a value of É of about 2 E+5Â Mâ1Â cmâ1.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Jorge S. Gancheff,