Mononuclear, dinuclear and polymeric cobalt(II) complexes built on 4-aryl-2,6-bis(2 '-pyrazinyl)pyridines

摘要

Two new multidentate nitrogen ligands containing a 2,6-bis(2'-pyrazinyl)pyridine (bpp) backbone were synthesized and characterized. The facile Krohnke condensation procedure allows for efficient synthesis and modification of this class of N-rich ligands. The metal-mediated self-assembly of these ligands along with a previously known derivative with Co(NCS)(2) was studied. X-ray structural analysis of the metal assemblies reveals that mononuclear, dinuclear and polymeric structures could be obtained based on the ligands used. Although in most cases including the previously reported results the coordination chemistry of bpp-based ligands involves only inner N-3 cavity, with the outer-N donors remaining uncoordinated, the introduction of a 3-pyridyl group to the 4-position of central pyridine of bpp is found to be critical for the synthesis of new coordination polymers. The thermal properties of these metal complexes have been studied. (C) 2017 Elsevier Ltd. All rights reserved.