5-(2-Pyridil)-1H-tetrazole complexes with Mo(iv) and W(iv) cyanides

Abstract

The reactions of tetrazole ligand derived from 2-cyanopyridine with K₃Na[Mo(CN)₄O₂]·6H₂O and K₃Na[W(CN)₄O₂]·6H₂O in water–ethanol solution result in isolation of two new complexes with the following formulae: (PPh₄)₂[Mo(CN)₃O(pdt)]·2H₂O (1) (Hpdt = 5-(2-pyridil)-1H-tetrazole) and (PPh₄)₂[W(CN)₃O(pdt)]·3H₂O (2). The complexes were characterized by elemental analysis, single crystal X-ray structure measurements, IR and UV-Vis spectroscopy, cyclic voltammetry measurement as well as thermogravimetric measurement. The X-ray crystal structure measurements indicated the presence of two coordination isomers in a single crystal. The pyridine nitrogen occupies both trans and/or cis position to the MO bond, which is explained by similar pK of pyridine and tetrazole nitrogen. The DTG measurements indicate the stabilization of tetrazole upon coordination.