Properties and structural characterization of copper(II) mixed complexes with 2,2′-bipyridyl and iminodiacetate or pyridine-2,6-dicarboxylate

Abstract

X-Ray analysis of the mixed complexes [Cu(bipy)(ida)]·6H₂O (1) and [Cu₂(bipy)₂(pydca)₂]·4H₂O (2b)(bipy = 2,2′-bipyridyl, ida = iminodiacetate, and pydca = pyridine-2,6-dicarboxylate) shows that different stereochemistries are involved in the solid state in spite of the similarity of the two chromophores around the copper(II) ion. In the crystals of (1) the copper is five-co-ordinate and the co-ordination polyhedron may be described as a distorted square pyramid. The crystal structure of (2b) consists of binuclear units in which Cu(bipy)₂ and Cu(pydca)₂ moieties are bound through an oxygen bridge, the former having a distorted square-pyramidal geometry, the latter a trigonal-bipyramidal arrangement. Cell parameters: (1)a= 11.200(7), b= 13.252(8), c= 7.975(7)Å, α= 66.8(1)β= 115.3(1), γ= 102.0(1)°, triclinic, space group P1; (2b)a= 13.103(6), b= 17.815(7), c= 15.302(7), β= 90.8(2)°, monoclinic, space group P2₁/c. Both structures have been solved by conventional Patterson and Fourier methods and refined to R factors of 0.043 and 0.041 respectively.