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Mixed complexes of 5-nitrosouracil derivatives: Synthesis and structural study of 6-amino-1,3-dimethyl-5-nitrosouracilato (N5,N6)-aqua-2,2′-bipyridine (N,N′)-copper(II) perchlorate hydrate and 2,2′-bipyridine (N,N′)-chloro-1,3-dimethylviolurato (N5,O6)-copper(II) hemihydrate

1998; Elsevier BV; Volume: 17; Issue: 10 Linguagem: Inglês

10.1016/s0277-5387(97)00436-1

1873-3719

F. Bélanger-Gariépy, R. Faure, Francisco Hueso‐Ureña, Miguel N. Moreno‐Carretero, Jorge A. Rodríguez-Navarro, J.M. Salas-Peregrín,

Lanthanide and Transition Metal Complexes

The mixed [Cu(DANU)(bipy)(H2O)]ClO4·H2O (1) and [Cu(DMV)(ipyl)Cl]·1/2H2O (2) complexes have been isolated from the reaction, in water/EtOH medium, of copper(II) perchlorate and chloride with 6-amino-1,3-dimethyl-5-nitrosouracil (HDANU) and 2,2′-bipyridine (bipy). It is noteworthy that, in the second complex, the uracil ligand is the 1,3-dimethyl-violurato monoanion (DMV), appeared from the hydrolysis of HDANU. In addition to X-ray diffraction studies, these compounds have been characterized from IR and EPR spectra and magnetic measurements (77–290 K). The crystal lattice of 1 is made up of discrete square pyramidal [Cu(DANU)(bipy)(H2O)]+ cations, a disordered perchlorate group and a water molecule. The coordination geometry about the metal centre is square pyramidal (N4+O). The basal positions are occupied by a bidentate DANU ligand, coordinated through the N15 and N16 donor positions, and a bipyridine ligand. A water molecule (CuO1W 2.193(3) Å) occupies the apical site. The compound 2 presents a similar molecular structure to that of 1 with the copper centre lying in a N3O+Cl environment. In this case, the basal positions are occupied by a bipy ligand and a DMV ligand coordinated through the N15 and O16 donor positions, instead of the DANU ligand found in the previous compound. The apical position is occupied in this case by a chlorine atom (CulCll 2.413(2) and Cu2C12 2.389(2) Å).