Syntheses, Structures, and Photoluminescent Properties of Three Silver(I) Coordination Polymers with 2-(4-Pyridyl)benzimidazole

Abstract

Three silver(I) coordination polymers, namely, [Ag2(PyBIm)2(H2O)2]SO4·H2O (1), [Ag3(PyBIm)3(μ2-SO4)(HSO4)]·3H2O (2), and [Ag2(PyBIm)2(μ2-SO4)]·4H2O (3) [PyBIm = 2-(4-pyridyl)benzimidazole] have been synthesized by hydrothermal methods. The Ag(I) atoms in 1−3 are all three coordinated, bridged by PyBIm ligands via NPy and NBIm donor atoms into a one-dimensional "zigzag" chain based on the [Ag2(PyBIm)2]2+ unit. The sulfate groups are not coordinated in 1, while they act as bridging ligands in 2 and 3; with the help of μ2-SO4, such "zigzag" chains are linked into a belt with a ternary-chain structural motif in 2; however, in 3, a two-dimensional network is observed. All the complexes display room-temperature photoluminescence in the visible region, which may be assigned to metal-to-ligand charge transfer.