Synthesis, crystal structures and photoluminescence of three new Mn(II) coordination polymers assembled from 2,4′-diphenic acid

Abstract

Three new metal coordination polymers, [Mn(Hdpa)2(4,4′-bipy)2] n (1), [Mn(dpa)(1,10-phen)(H2O)] n (2), and [Mn(dpa)(2,2′-bipy)] n (3) (H2dpa = 2,4′-biphenyl-dicarboxylic acid, 4,4′-bipy = 4,4′-bipyridine, 1,10-phen = 1,10-phenanthroline, and 2,2′-bipy = 2,2′-bipyridine), have been synthesized and characterized by elemental analysis, IR, and X-ray diffraction. Single-crystal X-ray analyses reveal that 2,4′-diphenic acid is a bridging ligand, exhibiting three coordination modes to link metal ions: μ 1-η 1: η 1/μ 0-η 0: η 0; μ 2-η 2: η 0/μ 1-η 1: η 0; and μ 2-η 1: η 1/μ 2-η 1: η 1. Intermolecular hydrogen bonds in 1 lead to a zigzag chain. In 2, the 2-D supramolecular arrays extended along b-axis through π–π interactions between 1,10-phen. The dinuclear paddle-wheel second building units (SBUs) constructed by four dpa2− ligands in 3 are linked by dpa2− into double-strand chains. The fluorescence of H2dpa and 1–3 are also determined.