Studies on metal complexes of isocytosine derivatives: The molecular structures of platinum(II) and platinum(IV) complexes of 2-hydrazino-4-hydroxy-6-methylpyrimidine.

The Pt(II) and Pt(IV) complexes of 2-hydrazino-4-hydroxy-6-methylpyrimidine (LH) were synthesized and their structures investigated.We found that Pt(II) and Pt(IV) ions form novel 1 : 1 and 1 : 2 complexes with LH, respectively.The Pt(II) complex of LH, [PtIICl2(LH)], is a square planar complex with a Pt(II) coordination number of four.On the other hand, in the [PtIVCl6](LHH)2 complex, one [PtIVCl6]2- group forms a double salt with two LHH+ molecules which are connected to each other by hydrogen bonds as shown by X-ray structure determination. Crystals of [PtIVCl6](LHH)2, C10H18Cl6N8O2Pt, belong to the space group P1^- with the unit cell dimensions, a=6.825(2), b=11.496(4), c=6.775(2)A, a=101.17(3)°, γ=85.69(3)°, V=506.(3)A3 and Z=1. The atomic parameters were refined to a final R value of 0.050 for 4441 reflections.The Pt(IV) ion is situated at the crystallographic center of symmetry.Six ligated Cl- ions and two protonated LHH+ are arranged symmetrically around the Pt(IV) ion, and the [PtIVCl6]2- complex ion takes an octahedral cooldination geometry.