Isomerization LMCT excited states

Irradiation of (he trans isomer leads to a different isomeric mixture of the chloro aquo species (66% cis, 34% trans) demonstrating that the two photolabilizations do not proceed via a single, common intermediate. These reactions occur with small quantum yields [0.003 for Eq. (p)], the result of the low-energy LMCT excited states that dominate the absorption spectra. For the d case, the orbital character of the lower energy LMCT transitions is (7TL) (dt2g) - (7r ) (t2g) and the resulting ES should not be substitution labile. 

Isomerization and polymerization reactions of alkenes and alkynes are to be expected because both the MLCT and LMCT excited states have diradical character. Both the tetracyanoethylene and dicyanoacetylene 7r-complexes of Pt(PPh3>2 undergo a photoinduced intramolecular oxidative addition reaction to give the cyano vinyl and cyano acetylide complexes of platinum(II) respectively ... 

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