Effects of the substituents of pyrazole/thiazine ligands on nuclearity of Cu(II) nitrate complexes

Abstract

Cu(H 2 O)(PzTz) 2 ](NO 3 ) 2 (1), [Cu(-NO 3 )(NO 3 )(DMPzTz)] n (2), and [{Cu(NO 3 )have been prepared and characterized by elemental analysis, electronic spectroscopy, IR spectroscopy, electron paramagnetic resonance spectroscopy, magnetic susceptibility measurements, and single-crystal X-ray diffraction. Influence of ligand size on coordination to Cu(II) has been analyzed. The three complexes are five-coordinate and the coordination geometry can be described as a distorted trigonal bipyramid for 1 or a distorted square pyramid for 2 and 3. As a consequence of the strain induced by the ligands, 1 is a monomeric complex cation whereas 2 is a polymer and 3 is a dimer.