Dimerization of Diruthenium Coordination Compounds via Olefin Metathesis

Diruthenium compounds containing an ω‐alkene‐α‐carboxylate ligand, Ru 2 Cl[D(3,5‐Cl 2 Ph) F] 3 [O 2 C(CH 2 ) n CH=CH 2 ] [ n = 1 ( 1a ) and 2 ( 1b )], were prepared from the reactions between Ru 2 Cl[D(3,5‐Cl 2 Ph)F] 3 (O 2 CCH 3 ) [D(3,5‐Cl 2 Ph)F = N , N′ ‐bis(3,5‐dicholorophenyl)formamidinate] and ω‐alkene‐α‐carboxylic acids. Both compounds 1a and 1b undergo olefin cross‐metathesis reactions catalyzed by (Cy 3 P) 2 Cl 2 Ru(=CHPh) to afford the dimerized compounds [Ru 2 Cl{D(3,5‐Cl 2 Ph)F} 3 ] 2 [μ‐O 2 C(CH 2 ) n CH=CH(CH 2 ) n CO 2 ] [ n = 1 ( 2a ) and 2 ( 2b )]. Molecular structures of compounds 1a / 1b and 2a / 2b were established by X‐ray diffraction studies, which revealed the formation of trans product only in the case of shorter tether ( 2a ) and a mixture of cis ‐/ trans isomers in the case of longer tether ( 2b ). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)