Unusual Dimeric Zn(II)-cytosine complexes: New models of the interaction of Zn(II) with DNA and RNA

Synthesis and crystal structure of two Zn(II) dimer complexes with 1-methylcytosine (1-MeC) are reported. In complex [Zn2Cl4(μ-1-MeC-O2,N3)2] (1), two 1-MeC ligands are bridging two ZnCl2 moieties. In [Zn2(1-MeC-N3)4(μ-SO4)2] · 2H2O (2), the sulfates act as bridging ligands and 1-MeC are linked via N3 to Zn(II) as terminal ligands. Both complexes represent the first examples of Zn(II)-pyrimidine dimers. The potential biological significance of 1 and 2 is discussed.