Conformational Analysis of Hexakis-DMF Nickel(II) Complex on the Basis of Density Functional Theory Computations

抄録

Density Functional Theory (DFT) investigations have been conducted for a hexakis-DMF nickel(II) complex cation [Ni(DMF)₆]²⁺ [hexakis(N,N-dimethylformamide-κO)nickel(II)dication] for the purpose of revealing the reasons for the structural features − an S₆ symmetry and a trigonal compression − observed by the single-crystal X-ray diffraction experiment, where DMF is an N,N-dimethylformamide molecule as a ligand. The DFT investigations have shown that there are only two conformers − S₆ and D₃ − for the complex cation [Ni(DMF)₆]²⁺, and the most stable conformer has been found to be the S₆ conformer, which is consistent with the crystal structure. In addition, the trigonal compression is reproduced by the DFT computation, indicating that the trigonal compression is the nature of the complex cation but not due to crystal packing. Moreover, inter-ligand hydrogen-bonds have been found to play important roles in determining the structure.