Quantum chemistry of OsCl ₆ ^2- photoaquation products and the reaction scheme

Quantum chemical calculations (CASSCF and XMCQDPT level of theory, IMCP-SR1 and SBKJC basis sets) of the structures and electronic absorption spectra of the Os ^IV Cl ₅ (H ₂ O) ^- and Os ^IV Cl ₅ (OH) ^2- complexes, which are the products of Os ^IV Cl ₆ ^2- photoaquation, were performed. The satisfactory agreement between the experimental and calculated spectra was achieved using both triplet and quintet manifolds. The dissociation of the aquacomplex with the formation of the hydroxocomplex was explained by the thermochemical data.