Ruthenium photoisomerization

Any proposed mechanism for the unprecedented transformation described by Equation 18 must account for the promotion of this photoisomerization by CO, although CO is not required by the stoichiometry. A possible initial step would be similar to that for the Ru3(CO)i2 fragmentation (Scheme 1). In this a Ru-Ru bond is broken concomitant with the movement of a CO from a terminal to a bridging site to form an unsaturated intermediate analogous to I. A speculative proposal along these lines is presented in Figure 5. The key feature of this proposal would be the formation of III with one unsaturated ruthenium, which could be captured by CO to promote the subsequent steps leading from the /1-methylidyne to the acyl... 

Photosubstitution at ruthenium(II)-bipyridyl complexes has been described for the polymer-bound complex [Ru (bipy)2 (pvp)2f", where pvp is poly(4-vinylpyridine). Reactivity is lower here than for equivalent monomeric complexes. " Photoisomerization cis trans) of [Ru(bipy)2(OH2)2] has been studied at the surface of hectorite, a layer silicate, and the results compared with those for aqueous solution. " ... 

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