Coordination geometries and cooperative ordering effects in copper(II) complexes with tridentate Schiff base dianions. I. Crystal and molecular structure and EPR investigation of N‐salicylideneglycinato‐2‐methylimidazole‐copper(II)

Abstract

AbstractN‐Salicyclideneglycinato(2‐methylimidazole)copper (II) — [Cu(salgly)(2‐MeIm)] — C13H13N3O3Cu — crystallizes in the monoclinic space group P21/c, a = 1 248.4, b = 1 157.3, c = 964.5 pm, β = 108.91°, Z = 4; structure determination with 1 504 significant reflections, R = 0.058. The molecular stucture of the complex is characterized by an approximately square coordination of CuII with O, N, O atoms of the tridendate dianion salgly2⊖ and the 3‐N atom of 2‐MeIm. The coordination polyhedron is completed to square pyramid by an apically coordinated carboxyl oxygen atom (bond distance 248 pm) from the neighboring complex molecule, thus forming zigzag chains oriented on parallel lines in the crystal structure. The EPR parameters of the title compound (g = 2.176, g = 2.146, g = 2.056) confirm the slightly disturbed antiferrodistortive ordering of the complex molecules quantitatively. From the cooperative gc tensor of a single crystal and the structural data orthorhombic molecular g components were evaluated. They were refined, in order to achieve a still better agreement with the EPR parameters of a series of comparable copper(II) complexes.