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)(2)Cl2Ru=CH(CH=CH)(n)CH=Ru(PCy3)(2)Cl-2 (n = 1, 2), were prepared by reacting 2 equiv. of the Grubbs first-generation catalyst (PCy3)(2)Cl2Ru=(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)(2)Cl2Ru=CHCH=CHCH=CH2. 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 (H(2)IMes)RuCl2(=CHPh)(3-bromopyridine)(2) allowed for ruthenium incorporation into polyacetylene, leading to the formation of polymers and oligomers with high ruthenium content. (c) 2006 Elsevier B.V. All rights reserved.