Synthesis and Characterization of [Co(tta)2(4,4′-bipy)2.CHCl3]n: A Coordination Polymer with Sulfur–Sulfur Interactions

Abstract

Coordination polymer [{Co(tta)2(4,4′-bipy)}n] (1) (tta = 4,4,4 trifluoro-1-(2-thienyl)-1,3-butanedionate; 4,4′-bipy = 4,4′-bipyridine) was synthesized by reacting [Co(tta)2-(H2O)2] with equivalent of 4,4′-bipy, whereby the aqua ligands in [Co(tta)2-(H2O)2] were replaced by 4,4′-bipy ligand. Thermal behavior, investigated via thermogravimetric analysis (TGA), revealed that 1 decomposes between 290 and 400 °C. The solid-state structure of 1 was confirmed by single-crystal X-ray diffraction, which established its polymeric nature of 1. Each monomer unit of 1 features a cobalt center in an octahedral coordination environment, with two equatorially chelating tta ligands and one axially oriented 4,4′-bipy ligand. Sulfur–sulfur interactions lead to the formation of a two-dimensional supramolecular network. In addition, compound 1 is stabilized by various intermolecular interactions, including C-H···π, C-F···F-C, and C-H···F-C contacts. Hirshfeld surface analysis and 2D-fingerprint plots were employed to further investigate the non-covalent intermolecular interactions in the solid state, providing strong evidence for their role in stabilizing the crystal structure.