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)2C12RuCH(CHCH)nCHRu(PCy3)2Cl2 (n = 1, 2), were prepared by reacting 2 equiv. of the Grubbs first-generation catalyst (PCy3)2C12Ru(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)2C12RuCHCH CHCHCH2. 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(CHPh)(3-bromopyridine)2 allowed for ruthenium incorporation into polyacetylene, leading to the formation of polymers and oligomers with high ruthenium content.

Graphical abstractOlefin Metathesis for Metal Incorporation (OMMI) was used for the stoichiometric attachment of ruthenium to both small and large polyenes. The complexes obtained through OMMI exhibit interesting structural, electronic, and reaction properties.Figure optionsDownload full-size imageDownload as PowerPoint slide