Synthesis, structures and characterization of two new supramolecular coordination complexes with the ambidentate ligand 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione (Hpot)

Abstract

Two new coordination supramolecular complexes based on a versatile and unsymmetrical 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione (Hpot) and MnII and NiII have been synthesized and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of MnCl2 · 4H2O with Hpot afforded a neutral mononuclear complex [Mn(pot)2(H2O)4] · 2H2O (1), which exhibits a three-dimensional (3-D) supramolecule through versatile intermolecular O–H ··· X (X=O, N and S) hydrogen bond interactions. When using NiCl2 · 6H2O instead of MnCl2 · 4H2O under similar reaction conditions, a neutral mononuclear complex [Ni(pot)2(H2O)4] (2) is also obtained, which does not exhibit intermolecular hydrogen bonds and π–π stacking interactions. It is very interesting that the pot anion exhibits different coordination modes in complexes 1 and 2. The IR spectra and the TGA for 1 and 2 have been investigated and discussed in detail.