Uracilato and 5-halouracilato complexes of Cu(II), Zn(II) and Ni(II). X-ray structures of [Cu(uracilato-N-1)(2)(NH3)(2)]center dot 2(H2O), [Cu(5-chlorouracilato-N-1)(2)(NH3)(2)](H2O)(2), [Ni(5-chlorouracilato-N-1)(2)(en)(2)]center dot 2H(2)O and [Zn(

摘要

Four new complexes of uracilato and 5-halouracilato with the divalent metal ions Cu(II), Zn(II) and Ni(II) were obtained and structurally characterized. [Cu(uracilato- N-1)(2)(NH3)(2)].2(H2O) (1) and [Cu(5-chlorouracilato-N-1)(2)(NH3)(2)](H2O)(2) (2) complexes present distorted square planar co-ordination geometry around the metal ion. Although an additional axial water molecule is present [Cu(II)-OH2 = 2.89 Angstrom (for 1) and 2.52 Angstrom (for 2)] in both cases, only in the complex 2 would be considered in the limit of a bond distance. The Zn(II) in [Zn(5-chlorouracilato-N-1)(NH3)(3)].(5-chlorouracilato-N-1) - (H2O) presents a tetrahedral co-ordination with three ammonia molecules and the N-1 of the corresponding uracilato moiety. A non-coordinated uracilato molecule is present as a counterion and a recognition between co-ordinated and free ligands, by means a tandem of H-bonds, should be mentioned. Finally, the complex [Ni(5-chlorouracilato-N-1)(2)(en)(2)] (H2O)(2) (where en is ethylenediamine) presents a typical octahedral trans coordination with additional hydrogen bonds between 5-chlorouracilato and the NH2 groups of ethylenediamine units