Olefin metathesis for metal incorporation: Preparation of conjugated ruthenium-containing complexes and polymers

Olefin Metathesis for Metal Incorporation (OMMI) was used for the stoichiometric attachment of ruthenium to both small and large polyenes. The dinuclear complexes (PCy3)2C12Rudouble bond; length as m-dashCH(CHdouble bond; length as m-dashCH)nCHdouble bond; length as m-dashRu(PCy3)2Cl2 (n = 1, 2), were prepared by reacting 2 equiv. of the Grubbs first-generation catalyst (PCy3)2C12Rudouble bond; length as m-dash(CHPh)) with 1 equiv. of the appropriate polyene (1,3,5-hexatriene for n = 1 and 1,3,5,7-octatetraene for n = 2). Use of excess hexatriene led to the formation of the monoruthenium complex (PCy3)2C12Rudouble bond; length as m-dashCHCHdouble bond; length as m-dash CHCHdouble bond; length as m-dashCH2. The mono- and di-ruthenium complexes exhibited marked differences in their spectroscopic and electrochemical properties, in addition to their Z–E isomerization rates. Nucleophilic attack of PCy3 on the end CH2 of the mono complex was observed, leading to both isomerization and phosphonium products. Extending the OMMI strategy to the second-generation catalyst was also done, despite the reduced initiation rate. The more reactive catalyst (H2IMes)RuCl2(double bond; length as m-dashCHPh)(3-bromopyridine)2 allowed for ruthenium incorporation into polyacetylene, leading to the formation of polymers and oligomers with high ruthenium content.