REACTIONS OF COORDINATED LIGANDS .8. PREPARATION OF (CO)5MR(H)PP(CL)RM(CO)5 (M=CR, MO, W R = PH, NET2) BY DEHYDROHALOGENATION OF (CO)5MPRHCL, AND SOME OF THEIR REACTIONS LEADING TO COMPLEXES WITH BRIDGING DIPHOSPHINE LIGANDS

Removal of HCI from (CO)5MPRHCl (M = Cr, Mo, W; R = Ph, NEt2) by treat ment with NEt3 has given the complexes (CO)5MPh(H)PP(CI)PhM(CO)5 (M = Cr, Mo, W) (1) and (CO)5CrNEt2(H)PP(CI)NEt2Cr(CO)5 (2) containing brid ging diphosphine ligands. Surprisingly, (CO)5CrCl2PPCl2Cr(CO)5 (3) was formed from treatment of (CO)5CrPHCl2 with NEt3. Reaction of 1 with t etrabutylammoniumfluoride, of 2 with gaseous HCI, and of 3 with MeOH g ave (CO)5CrPh(H)PP(F)PhCr(CO)5 (4), (CO)5CrCl(H)PPCl2Cr(CO)5 (5) and ( CO)5Cr(MeO)2PP(OMe)2Cr(CO)5 (6) respectively. Except for Cl2PPCl2, the diphosphine ligands in 1-6 are unknown in the free state. Attempts to abstract HCI from 1 to give the diphosphene complex (CO)5CrPhP=PPhCr( CO)5 failed.