Study of the [Cr(H2O)5NO]2+ complex via density functional theory

On the basis of density functional theory, the spin ground state of chromium-nitrosyl complex [Cr(H2O)(5)NO](2+) (S = 1/2) is studied via B3LYP hybrid method. Its vibrational frequencies, atomic charges, and spin densities are analyzed. The excitation energies are evaluated using the CIS method. Our calculated N-O stretching frequency and excitation energies are in good agreement with the IR and UV-vis data. The related Cr-I(H2O)(6)(+), Cr-II(H2O)(6)(2+), and Cr-III(H2O)(6)(3+) complexes are employed as the reference compounds to de termine the characteristics of the central Cr. Results indicate that the effective Cr oxidation state is close to Cr(I).