Electronic peculiarities of the excited states of [RuN_5C] ~+vs. [RuN_6]~(2+) polypyridine complexes: Insight from theory

摘要

The ground state, oxidized ground state, ~3MLCT and ~3MC excited states have been studied by DFT and TDDFT for two Ru(ii) complexes bearing an N_6 or N_5C coordination sphere. The effect of replacing one Ru-N dative bond by one Ru-C covalent bond have been studied and quantified on their ground state by the means of geometry optimization, NBO analysis and calculation of their IR vibrations. IR fingerprints of the Ru-C bond have been found at 945 and 1113 cm~(-1). In addition, this study confirmed and quantified the effects of N→C ~- substitution on the spectroscopic properties of the [RuN _5C]~+ complex: a broader and bathochromically-shifted absorption spectrum, a smaller ground-~3MLCT energy gap and a highly energetic ~3MC state are the major characteristics of the carbon-containing monocationic complex.