Double and triple stranded mesocates containing the bis(bidentate) bridging ligand 1,3-bis(pyridine-2-carboxamide)benzene. Structure, properties and DNA interaction
作者:MaAngeles Palacios、Antonio Rodríguez-Diéguez、Angelo Sironi、Juan Manuel Herrera、Antonio J. Mota、Virtudes Moreno、Joan Cano、Enrique Colacio
DOI:10.1039/b905330a
日期:——
The double stranded CuII2 metallacyclic complex of formula [Mn(hfac)2(H2O)2][Cu2(mbpb)2(CH3CN)2] (1) and the triple stranded NiII2, ZnII2 and CoIII2 metallacyclic complexes of formula [M2(Hmbpb)3]X·nH2O (M = ZnII, X = NO3− (2), n = 17; M = NiII, and X = ClO4− (3), n = 15) and [Co2(mbpb)3]·19H2O (4) (H2mbpb is the bisbidentate dinucleating bridging ligand, 1,3-bis(pyridine-2-carboxamide)benzene) have been prepared and structurally characterised. Their X-ray structures show that inside the dinuclear molecules metal ions are bridged by either fully or semideprotonated bisbidentate ligands, which are coordinated through the pyridine and amidato nitrogen donor atoms. In 1, the neutral metallamacrocycle dinuclear entities [Cu2(mbpb)2(CH3CN)2] and the [Mn(hfac)2(H2O)2] molecules are connected by hydrogen bonds to afford a 1D system. These intermolecular interactions overcome the expected intradinuclear weak ferromagnetic interaction leading to an overall weak antiferromagnetic interaction. The Ni2 complex exhibit ferromagnetic coupling between the metal ions through the bridging ligand with JNi–Ni = 3.1 cm−1. DFT calculations were performed to estimate the value of the exchange magnetic coupling inside the dinuclear unit in 1 and to confirm that the spin polarisation mechanism is responsible for the ferromagnetic coupling. AFM studies show that the ZnII2 and NiII2 cationic complexes interact with pBR322 DNA producing supercoiled forms in higher extension as well as kinks and cross linking.
双链CuII2金属环状复合物,其化学式为[Mn(hfac)2(H2O)2][Cu2(mbpb)2(CH3CN)2](1),以及三链NiII2、ZnII2和CoIII2金属环状复合物,其化学式为[M2(Hmbpb)3]X·nH2O (M = ZnII,X = NO3− (2),n = 17;M = NiII,X = ClO4− (3),n = 15)和[Co2(mbpb)3]·19H2O (4) (H2mbpb是双齿双核桥连配体,1,3-双(吡啶-2-甲酰胺)苯)已经制备并进行了结构表征。它们的X射线结构显示,在双核分子内部,金属离子由完全或半质子化的双齿配体桥连,通过吡啶和酰胺氮供体原子进行配位。在1中,中性金属环状双核实体[Cu2(mbpb)2(CH3CN)2]和[Mn(hfac)2(H2O)2]分子通过氢键连接,形成一维系统。这些分子间相互作用克服了预期的双核内弱铁磁相互作用,导致