A New Nitrosyl-bridged Bimetallic Nitroprusside Complex:Synthesis, Crystal Structure, Supramolecular Self-assembly and Spectral Behavior of Interactions with DNA

摘要

A new nitrosyl-bridged bimetallic nitroprusside complex, [Ba(phen)_3(H_2O)] [Fe(CN)_5NO]?1.5phen·2H_2O (phen = 1,10-phenanthroline) (1), has been synthesized and characterized by elemental analysis and single crystal X-ray diffraction. The crystal structure analysis reveals that complex 1 crystallizes in the triclinic space group Pi. The asymmetric structural unit is comprised of one [Ba(phen)_3 (H_2O)]~(2+) complex cation, one [Fe(CN)_5NO]~2- complex anion, 1.5-uncoordinated phenanthroline molecules and two lattice water molecules. The complex ions are linked into a 1D chain-like arrangement by the trans CN and NO groups in nitroprusside. The six-coordinated Fe-atom forms a distorted octahedral coordination configuration, and the Ba-atom has a nine-coordinate monocapped antipr-ismatic geometry. Five types of π-π stacking interactions of phenanthroline and some intra- and intermolecular hydrogen bonds are observed in the 3D supramolecular self-assembly. Absorption spectroscopy, fluorescence titration and viscometry studies of the interaction between complex 1 and calf thymus DNA indicate that complex 1 is a moderate metallo-intercalator with the intrinsic binding constant of 3.70 × 10~4 M~(-1)and the linear Stern-Volmer quenching constant of 5.98 × 10~4 M~(-1).