Density functional theory of the iron-nitrosyl (S=3/2) complex

On the basis of density functional theory (DFT), the iron-nitrosyl complex Fe[Me(3)TACN](NO)(N-3)(2) (S = 3/2) is studied via the B3LYP hybrid method. Its Raman vibrational frequencies, atomic net charges, and spin densities are analyzed. The related complexes Fe(NH3)(6)(n+) (n = 1, 2, and 3) are employed as reference compounds to determine the characteristics of the central iron. Our results indicate that the S = 3/2 spin ground state of Fe[Me(3)TACN](NO)(N-3)(2) is best described by the presence of Fe-II (S = 2) anti-ferromagnetically coupled to NO0 (S = 1/2) yielding Fe-II[Me(3)TACN](NO0)(N-3(-))(2). This is clearly different from the previous Fe-III-NO- theoretical assignment. (c) 2005 Wiley Periodicals, Inc.