Organoplatinum Dendrimers

A route to dendrimeric organoplatinum complexes is described by a strategy involving oxidative addition of the C−Br bonds of 4,4‘-(BrCH 2 ) 2 -2,2‘-(C 5 H 3 N) 2, A, to [PtMe 2 (bu 2 bipy)], 1, bu 2 bipy = 4,4‘-di- tert -butyl-2,2‘-bipyridine, to give 4,4‘-{BrPtMe 2 (bu 2 bipy)CH 2 } 2 -2,2‘-(C 5 H 3 N) 2, 2, followed by regeneration of a [PtMe 2 (NN)] functionality by reaction of the free diimine group of 2 with [Pt 2 Me 4 (μ-SMe 2 ) 2 ], B, to give 4,4‘-{BrPtMe 2 (bu 2 bipy)CH 2 } 2 -2,2‘-(C 5 H 3 N) 2 PtMe 2, 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-(BrCH 2 ) 4 C 6 H 2 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 .