Organoplatinum dendrimers

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 [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)CH2}(2)-2,2'-(C5H3N)(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)(mu-SMe(2))(2)], B, to give 4,4'-{BrPtMe(2)(bu(2)bipy)CH2}(2)-2,2'-(C5H3N)(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-(BrCH2)(4)C6H2 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.