RUTHENIUM OR FERROCENYL HOMOBIMETALLIC AND RUPDRU AND FEPDFE HETEROTRIMETALLIC COMPLEXES CONNECTED BY UNSATURATED, CARBON-RICH -C-CC6H4C-C-BRIDGES

The reaction of 1,4-diethynylbenzene with cis-RuCl2(dppe)(2) and iodof errocene gave the homobimetallic systems Cl(dppe)(2)Ru-C=CC6H4C=C-Ru(d ppe)(2)Cl (2) and (eta 5-C5H5)Fe(eta(5)-C5H4)-C=CC6H4C= C-(eta(5)-C5H4 )Fe(eta(5)-C5H5) (3), respectively. The organometallic terminal alkyne s Cl(dppe)(2)Ru-C=CC6H4C=CH (6) and (eta(5)-C5H5)Fe(eta(5)-C5H4-C=CC6H 4C=CH) (8), obtained by desilylation of the corresponding complexes Cl (dppe)(2)Ru-C=CC6H4C=(CSiPr3)-Pr-i (5) and eta(5)-C5H5)Fe(eta(5)-C5H4- C=CC6H4C=(CSiPr3)-Pr-i) (7), were used as key starting products for ac cess to the heterotrimetallic systems ns-(P(n)Bu(3))(2)Pd[-C=CC6H4C=C- Ru(dppe)(2)-Cl](2) (10; 53%) and )(2)Pd[(-C=CC6H4C-C5H4-eta(5))Fe(eta( 5)-C5H5)](2). (11; 73%) by reaction with PdCl2(PBu(3))(2). The cyclic voltammetry studies of the complexes 2 and 3 have shown that the elect rochemical response was strongly dependent on the connection type betw een the two terminal organometallic fragments and the organic bridge a nd that the insertion of the palladium moiety trans-Pd(PBu(3))(2) in t he trimetallic complexes 10 and 11 induced totally different electroch emical behavior.