Unusual platinum complexes of deprotonated 1-methylcytosine: bis(.mu.-1-methylcytosinato-N3,N4)-bis(cis-diammineplatinum(II)) dinitrate dihydrate, [(NH3)2Pt(C5H6N3O)2Pt(NH3)2](NO3)2.2H2O, and [diaquahydrogen(1+)][bis(.mu.-1-methylcytosinato-N3,N4)-bis(cis-nitrodiammineplatinum)(Pt-Pt) dinitrate, (H5O2)[(NH3)2(NO2)Pt(C5H6N3O)2Pt(NH3)2(NO2)](NO3)2