G. Henig et al., PHOSPHINOMETHANIDE VERSUS PHOSPHINOENOLATE - THERMODYNAMICAL PREFERENCE FOR A 3-MEMBERED INSTEAD OF A 5-MEMBERED CHELATE RING, Chemical communications, (24), 1997, pp. 2349-2350
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-membe
red RuCP ring in the latter is confirmed by X-ray crystallography.