1,Synthesis of a Library of Iridium-Containing Dinuclear Complexes with Bridging PNNN and PNNP Ligands (BL),[LM(mu-BL)M'L']BF_4.2.Preparation,Basic Coordination Properties,and Reactivity of the Carbonyl Complexes

摘要

A series of dinuclear carbonyl complexes with PNNP and PNNN ligands,[(L)M(PNNX)M'(L)]BF_4 (X = P,N;M(L),M'(L') = Ir(CO)_2,Rh(CO)_2,Pd(allyl)),have been prepared by carbonylation (1 atm) of the corresponding cod complexes,and the Rh/Ir complexes have been further converted to mu-eta~1:eta~2-acetylide complexes,where effective pi-back-donation to the acetylide ligand is essential to stabilize them.On the basis of the stability of the acetylide complexes,the pi-donating ability of the metal fragment in the PNNX system is estimated to be (P,N)Rh > (P,N)Ir > (N,N)M.The dinuclear PNNX complexes catalyze alkyne hydrogenation,alkene hydroformylation,and allylation of aniline with allyl alcohol,and,for the allylation,a dinuclear mechanism involving activation of allyl alcohol by interaction with a CO ligand is proposed.