Structures and Electronic Spectra of Aquadiiminebis(succinimidato)copper(II) Complexes with Square Pyramidal [CuN4O] Chromophores (Diimine = 1,10-Phenanthroline and 2,2′-Bipyridine)

Abstract

Copper(II) complexes [Cu(succim)2(phen)H2O]·H2O (1) (succim = succinimidate, phen = 1,10-phenanthroline) and [Cu(succim)2(bpy)H2O] (2) (bpy = 2,2′-bipyridine) were prepared and the crystal structures were determined by X-ray crystallography. The coordination geometries are found to be five-coordinated square-based pyramidal [CuN4O] for each complex. Crystal data for complex 1 are monoclinic with space group P21/n; a = 9.602(4), b = 12.003(4), c = 17.618(4) Å; β = 100.38(3)°; V = 1997(1) Å3; Z = 4. Crystal data for complex 2 are monoclinic with space group P21/n; a = 9.616(2), b = 11.616(3), c = 15.871(2) Å; β = 90.61(2)°; V = 1772.8(6) Å3; Z = 4. The axial Cu–O(water) bond distances of the present complexes (2.548(5) Å for 1 and 2.673(4) Å for 2) are appreciable longer than those of other square pyramidal trans-[CuN4O] complexes. The diffuse reflectance spectra showing a broad peak at about 17000 cm−1 were analyzed by means of Gaussian curve fitting and angular overlap model (AOM) calculations with respect to dxy, dyz, and dzx orbitals distributing in the [CuN4] basal plane. According to the analyses, transferability of AOM parameters is valid for succim. The ligand field of bpy can be described by the same parameters as py (py = pyridine). However, it is necessary to set a larger π-bonding AOM parameter for phen than that of py to reproduce the experimental results. The reason for this is out-of-plane lone pairs and π-conjugation of phen. The assignment of the one-electron orbital sequences is presumed to be dx2−y2 > dz2 > dxy > dyz > dzx based on the AOM calculations for each complex.

Synthesis and structural characterization of a novel peroxo bridged dinuclear cobalt(III) complex of succinimide showing three varieties of hydrogen bonding interactions

“…These results are in agreement with previous reports. [7][8][9][10][11][12][16][17] The presence of water in 1 is evidenced by the strong signal at 3437 cm -1 . The observed signals at 886 and 532 cm -1 are assigned for the vibrations of the peroxo moiety which is in accordance with literature reports 24,25 .…”

“…7,8 Various aliphatic amine derivatives of metal(II)-succinimidato complexes have been synthesized and recently some Cu(II)-succinimidato complexes have been characterized by X-ray diffraction. [9][10][11][12][13][14][15][16][17] The literature survey shows that the copper complexes of succinimide have been studied extensively, while there is no report on cobalt complexes of succinimide. Ethylenediamine (en), its salts, and its derivatives are frequently found in drugs as well as biologically important molecules.…”

trans-Bis(4-aminopyridine-κN)bis(succinimidato-κN)copper(II) dihydrate

“…Komorita & Kushi, 2001). Furthermore, five-coordinate CuN 4 O or six-coordinate CuN 4 O 2 square-bipyramidal chromophores have been reported for cis-forms with bidentate diimine (Akitsu et al, 1999) or bidentate amine (Akitsu & Komorita, 2002). However, the related Cu II complexes with amine ligands containing two different coordinating N atoms have not been reported so far.…”