| Abstract
| - Infrared spectra of unstable species such as CO-free ruthenium tetraphenylporphyrin RuTPP and RuCOTPP(species with vacant coordination sites) isolated in solid argon at 8 K have been recorded. Selective depositionconditions allow the isolation of either RuTPP and RuCOTPP or RuCOTPP and Ru(CO)2TPP. This dependson the preparation conditions of the sample. A specific Ru−CO bending mode has been characterized at590.1 cm-1 for Ru(CO)2TPP. The behavior of each vibrational mode of RuTPP, RuCOTPP, and Ru(CO)2TPPhas been analyzed. Modes such as γ8 at 721.3 cm-1 (out-of-plane stretching mode γ(Cβ-H)sym) and ν41 at1342.8 cm-1 (νCα-N coupled with δCα-Cm) reflect the charge transfer in the porphyrin. Indeed, the addition ofone or two CO ligands to RuTPP reduces the charge transfer between the metal center and the porphyrin,which appears as an increase in the frequency of the ν41 mode and in a decrease in that of the γ8 mode.
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