Rhodium complexes cyclo-octa-1,5-diene

CsHi2RhCl]2 is formed from which the free cyclo-octa-1,5-diene may be obtained by displacement, without isomerization. Obviously, cyclo-octa-dienes are isomerized readily by aqueous solutions of rhodium trichloride but only the 1,5-diene forms a stable binuclear rhodium complex. The Group VI metal carbonyls also isomerize cyclo-octa-1,3-diene giving... 

Note added in proof In the preparation of rhodium and iridium complexes from cyclo-octa-1,5-diene, however, all the uncomplexed olefin is converted to the 1,3-diene. The same isomerization is catalyzed by tertiary phosphine complexes of rhodium and iridium, and the 1,4-diene can be detected as an intermediate (117a). 

Hexafluorobut-2-yne adds to the 1,4-positions of the rhodiunv-acetyl-acetonate ring of acetylacetonato(cyclo-octa-l,5-diene)rhodium, and this adduct reacts with hexakis(trifluoromethyl)benzene, formed in situ, to give complex (86a), in which the cyclo-octadiene has been displaced. This structure is confirmed by single-crystal A -ray diffraction. The same product is formed from the corresponding (hexachloronorbomadiene)rhodium complex, but with acetylacetonatobis(ethylene)rhodium or the (ethylene)-(tetrafluoToethylene)rhodium complex, the cyclohexadiene complex (87), in which the one molecule of ethylene is incorporated into the co-ordinated... 

A number of metal complexes of cyclo-octa-1,5-diene are reported from cobalt, palladium, rhodium, iridium, and copper(i) systems. Bis(cyclo-octa-l,5-diene)nickel has been used to couple alkenyl halides. An X-ray study of (356), obtained by proton abstraction from tricarbonylcyclo-octa-l,5-diene-... 

Hetorogenized Catalysts.—Reaction of [Ru(NH3)60H] + with a Faujasite-type zeolite gives a supported Ru complex, which effects hydroformylation of ethylene the catalytic species may be ruthenium clusters that are trapped in the zeolite cages. The effect of reaction conditions upon the selectivity of the hydroformylation of methyl methacrylate with [RhH(CO)(PPh3)3] or its polymer-anchored analogue has been investigated and hydroformylation of hex-l-ene and cyclo-octa-1,5-diene has been carried out with cobalt, rhodium, and platinum-tin complexes anchored to an ion-exchange resin via quaternary amino-phosphines. ... 

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