Convergent Route to Organometallic Dendrimers Composed of Platinum-Acetylide Units

Abstract

The third-generation dendrimer with 45 platinum atoms (shown schematically) was synthesized efficiently by a convergent methodology in which two different trialkylsilyl groups (symbolized by the nodal points) are used to protect the bridging triethynylbenzene derivatives. PT=[Pt(PEt ) ].

Polyynes

“…Early reports include the works of Takahashi [124] and Stang [125] on the construction of metallodendrimers using the respective triethynylmesitylene and triethynylbenzene as the organic framework. Both divergent [124,126] and convergent [127] syntheses of metallodendrimers of this class using a series of Cu-catalyzed dehydrohalogenation reactions have been reported. Recently the synthesis of the sixth-generation platinumcontaining organometallic dendrimers of up to 189 platinum atoms, via a divergent approach, has been reported [126].…”

Where organometallics and dendrimers merge: the incorporation of organometallic species into dendritic molecules

“…Takahashi has employed a platinum-acetylide functionality as the basis for the structure of numerous dendrimers [75,76]. Stang and coworkers concurrently reported the synthesis of essentially identical Pt acetylide dendrimers, employing a 1,3,5-substituted benzene core instead of mesityl [77].…”

Organometallic Polymers of the Transition Metals

“…[317][318][319][320][321] The synthesis of a first generation platinum acetylide dendrimer is shown in Scheme 73 via reaction of a chloro-substituted platinum complex with an ethynyl-functionalized dendron in the presence of CuI. Dendrimers with up to 45 platinum units were synthesized using this methodology.…”

“…Dendrimers with platinum and palladium alkynyl groups were also synthesized by Takahashi and coworkers. [318] Alkynylruthenium dendrimers have been examined by Humphrey and coworkers, and the NLO properties of these highly branched polymers were examined. [320,321] Scheme 66.…”