Synthesis and DNA-binding properties of cationic 2,2′:6′,2"-terpyridineplatinum(II) complexes containing 1,2- and 1,7-dicarba-closo-dodecaborane(12)

The first examples of DNA metallointercalators containing a dicarbacloso-dodecaborane(12) (carborane) moiety are presented. Treatment of the labile platinum(II) complex [Pt(OTf)(terpy)](+) (terpy = 2,2':6',2"-terpyridine) with the 1,2-carborane monothiol derivatives 1-HS(CH2)(n)-1,2-C2B10H11 (n = 0, 1) or the novel 1,7-carborane ligand, 1-HSCH2-1,7-C2B10H11, affords the stable, brightly colored species [Pt(1-S(CH2)(n)-1,Z-C2B10H11)(terpy)](+) (Z = 2, n = 0, 1; Z = 7, n = 1) in good yield and purity. Preliminary DNA-binding experiments with calf-thymus DNA indicate an intercalative interaction by the platinum(II) complexes at high r(f) values.