Abstract A new unsymmetrical geminal dianion that contained both a phosphine oxide moiety and a phosphine sulfide moiety has been synthesized. Its reactivity towards Ru II was explored, which led to the formation of a highly reactive carbene complex that evolved at room temperature to yield a kinetic orthometalated Ru II complex through C [BOND] H activation of the phenyl group of the phosphine oxide moiety. This insertion was found to ...