Phosphinomethanide versus phosphinoenolate: thermodynamical preference for a three- instead of a five-membered chelate ring
Abstract
The phosphinoenolate complex 4, which is prepared stepwise from [(mes)RuCl2]2 1 via the neutral and cationic compounds 2 and 3 as isolated intermediates, rearranges slowly in benzene to the thermodynamically more stable phosphinomethanide isomer 5; the presence of a three-membered RuCP ring in the latter is confirmed by X-ray crystallography.