Formation of Strong OH2···-O2C Hydrogen Bonds in a Trinuclear Core-Based Nickel 1,3,5-Benzenetricarboxylate Coordination Polymer

The nickel 1,3,5-benzenetricarboxylate (1,3,5-btc3-) coordination polymer, [Ni6(μ-OH2)4(1,3,5-btc)4(H2O)12]n (1), has been synthesized using a hydrothermal reaction. Trinuclear nickel cores constructed from the μ-OH2 and carboxylate bridges are linked by the 1,3,5-btc3- ligands, forming a two-dimensional network. The μ-OH2 molecules form strong hydrogen bonds with the free oxygens of the carboxylate groups in the trinuclear clusters. A structural phase transition occurs around 373 K and is categorized as a second-order phase transition.采用水热反应合成的镍1,3,5-苯甲酸三羧酸盐（1,3,5-btc3-）配位聚合物[Ni6(μ-OH2)4(1,3,5-btc)4(H2O)12]n (1)，其三核镍核由μ-OH2和羧酸盐桥连接，并通过1,3,5-btc3-配体相互连接，形成二维网络结构。μ-OH2分子与三核簇中羧酸基团游离氧原子形成强氢键。该聚合物在约373 K时发生结构相变，被归类为二级相变。