Synthesis, structure and characterisation of (μ-aqua)(diaqua) (μ3-benzene-dicarboxylate-κO1,O2)strontium(II) coordination polymer

Abstract

The hydrothermal synthesis and structural elucidation is reported for the compound with formula [Sr(terephthalate)(H2O)3]. The strontium (2+) ion is 8-coordinated with 2 waters, 1 bridging water, and a triple bridging 1 benzene-dicarboxylate (terephthalate) generating a zig-zag Sr-O-C-O-Sr chain. The terephthalate anion has only one COO- group coordinating to 3 Sr ions: chelating to the central one, and exo bridging, using each one O to 2 neighboring Sr ions along a-crystallographic axis; thereby forming a zig-zag-like one-dimensional coordination polymer. One water molecule provides additional bridge between the metal ions with a Sr-Sr distance of 3.808(8) Å. From the non-coordinating anionic COO- group, each O accepts 3 hydrogen bonds from both monodentate and bridging water molecules, with O-O contact distance between 2.739 and 2.962 Å, thus bridging the chains into a 3D-hydrogen bonding network. The thermal gravimetry is discussed, and an analysis of hydrogen bonding by DFT theoretical calculations is presented. © 2013 Elsevier B.V. All rights reserved.