PERFORMANCE OF DFT FUNCTIONALS FOR THE CALCULATION OF EPR HYPERFINE COUPLING CONSTANTS FOR SOME 3d TRANSITION METAL COMPLEXES

摘要

We have investigated the performance of several DFT functional for the calculation of EPR spectral parameter hyperfine coupling constants for some 3d transition metal complexes, namely [Cu (COM, [Ni(CO)sH] and [Mn (CO)s]. For these calculations, BHPW91, B3LYP, B3PW91, BLYP, BPW91, BP86, BHP86 functionals have been used and the results obtained have been compared with experimental values. The hyperfine coupling constant values obtained from different density functionals have been found in the order of BLYP > BP86 > BPW91 > B3LYP > B3PW91 > BHLYP > BHPW91 > BHP86 > EXP for [Cu(CO)_3], BHPW91 > BHP86 > BHLYP > B3PW91 > BLYP > BP86 > BPW91 > B3LYP > EXP for [Mn (CO)_5] and BHPW91 > BHP86 > BHLYP > B3PW91 > B3LYP > BLYP > BPW91 > BP86 > EXP for [Ni(CO)_3H] complex. We have inferred that although the results obtained by some of the DFT functionals are in close agreement experimental values but the performances of the different functionals for different transition metal complexes are not same. The performance of the functional BHP86 has been found better for [Cu (CO)_3], BP86 for [Ni(CO)_3H] and B3LYP for [Mn(CO)_5] metal complex.