BONDING PROPERTIES OF CU(II)-N-CHROMOPHORES: SPECTROSCOPY AND ELECTRONIC STRUCTURES OF HISTAMINE COPPER(II) COMPLEXES. MOLECULAR STRUCTURES OF BIS (HISTAMINE) BIS (PERCHLORATO) COPPER (II) AND CHLOROETHYLENEDIAMINEHISTAMINE-COPPER(II) CHLORIDE

Abstract

Abstract The crystal and molecular structures of [Cu(hmH)2(ClO4)2] (1) and [Cu(hmH)(en)Cl]Cl (2) (hmH = histamine; en = ethylenediamine) have been determined by three-dimensional X-ray diffraction data. Complex 1 crystallizes in monoclinic, P21/c, with a = 8.271(3), b = 13.659(4), c = 8.080(2) A, β = 99.83(2)°, Z = 2, R = 0.039 and Rw = 0.048; complex 2 is orthorhombic, Pbca, with a = 10.093(3), b = 15.063(4), c = 16.819(5) A, Z = 8, R = 0.035, and Rw = 0.038. The Cu(II) ion in 1 is coordinated centrosymmetrically by two histamine ligands forming an equatorial plane, Cu-N(ImH) 2.005(4) A and Cu-N(NH2) 2.035(4) A, and by two perchlorate anions on the elongated z axis, Cu-O 2.608(4) A. The Cu(II) ion in 2 is square pyramidal with one ethylenediamine, mean Cu-N 2.030 A, and one histamine, Cu-N(ImH) 1.993(4) A and Cu-N(NH2) 2.041(4) A, forming the basal plane and a chloride ion at the apex, Cu-Cl 2.609(2) A. The puckered histamine chelate rings of both complexes are bound strongly by the imidazole moieties, b...