On Metal-Modified Nucleobase Triples and Quartets

frans'-Diamineplatinum(II), Nucleobases, 9-Methyladenine, Synthesis, X-Ray Linking three nucleobases by two metal ions M of linear coordination geometry leads to metal-modified base triples. With M = mzns-(amine)2Ptn, the bases are forced into an essen­ tially coplanar fashion with interbase H bonding maintained in many cases. The model nucleo­ base triples described here are of general composition {[frart5-(amine)2PtB]2(9-MeA)}"+ with two nucleobases B bound via Pt to N 1 and N 7 of 9-methyladenine (9-MeA). The X-ray structure of a precursor, {[fra«5-(CH3NH2)2PtCl]2(9-MeA)}(C104)2, is briefly described. The generation of metalated, cyclic nucleobase quartets and their expected structures are dis­ cussed and ways towards larger macrocyclic metal compounds are pointed out.