Fast orthometalation reactions at a binuclear dirhodium(II) complex. Synthesis, crystal structure and reactivity of Rh 2(O 2CCH 3) 3[(C 6H 4)PPh 2]·(HO 2CCH 3) 2

Abstract

From the reaction of Rh 2(O 2CCH 3) 4(MeOH) 2, in hot acetic acid with PPh 3 the monometalated intermediate Rh 2(O 2CCH 3) 3[(C 6H 4)PPh 2](HO 2CCH 3) 2 has been isolated and characterized by an X-ray study. This compound rapidly reacts with an excess of PPh 3 in dichloromethane at room temperature to give Rh 2(O 2CCH 3) 2-[(C 6H 4)PPh 2] 2(PPh 3) 2 with a head-to-tail structure. The same procedure at higher temperatures gives a mixture of this compound and another doubly metalated compound with a head-to-head structure.