Organoplatinum Dendrimers

Abstract

A route to dendrimeric organoplatinum complexes is described by a strategy involving oxidative addition of the C−Br bonds of 4,4'-(BrCH2)2-2,2'-(C5H3N)2, A, to [PtMe2(bu2bipy)], 1, bu2bipy = 4,4'-di-tert-butyl-2,2'-bipyridine, to give 4,4'-{BrPtMe2(bu2bipy)CH2}2-2,2'-(C5H3N)2, 2, followed by regeneration of a [PtMe2(NN)] functionality by reaction of the free diimine group of 2 with [Pt2Me4(μ-SMe2)2], B, to give 4,4'-{BrPtMe2(bu2bipy)CH2}2-2,2'-(C5H3N)2PtMe2, 3. Repetition of this cycle has given dendrimers containing 6, 7, and 14 platinum atoms. The structure of 3 has been determined crystallographically. The above complexes containing 1, 3, or 7 platinum atoms react with the tetrafunctional core 1,2,4,5-(BrCH2)4C6H2 in a 4:1 ratio by oxidative addition of the C−Br bonds to the platinum(II) center to give dendrimers containing 4, 12, or 28 platinum atoms, respectively. An oligomeric dendrimer is prepared by reaction of A with B.