Zirconium(IV) Tris(phosphinoamide) Complexes as a Tripodal‐Type Metalloligand: A Route to Zr–M (M = Cu, Mo, Pt) Heterodimetallic Complexes

Treatment of ZrCl 4 with 3 equiv. of Li(PPh 2 NR) (R = t Bu, i Pr) gives tris(phosphinoamide)zirconium complexes, (PPh 2 NR) 3 ZrCl [R = t Bu ( 1a ), i Pr ( 1b )], in high yield. Crystal structures of 1a , b show that three phosphorus atoms are coordinated to the zirconium center in the solid state, whereas variable temperature NMR studies indicate a reversible coordination/dissociation process of three phosphorus atoms in the solution state. Reaction of 1a , b with CuCl give rise to the formation of Zr–Cu heterodimetallic complexes, ClCu(Ph 2 PNR) 3 ZrCl [R = t Bu ( 2a ), i Pr ( 2b )]. The molecular structures of 2a , b show that the Cu atom adopts a pseudotetrahedral coordination geometry with tripodal phosphorus moieties and a chlorine atom, whereas the ligand arrangement around the Zr atom is trigonal bipyramidal with the linear Cl–Zr–Cu axis at the apical site. A Zr–Mo heterodimetallic complex, (CO) 3 Mo(Ph 2 PN i Pr) 3 ZrCl ( 3 ), is synthesized from 1b and Mo(CO) 3 (CH 3 CN) 3 , in which the ligands around the Mo center are arranged octahedrally, and three phosphorus moieties are coordinated in the fac ‐P 3 fashion. The reaction of 1b with a square planar Pt II precursor, such as (COD)PtCl 2 , is unique and gives (κ 2 ‐Ph 2 PN i Pr)Pt(Ph 2 PN i Pr) 2 ZrCl 3 ( 4 ), which is the first example of a Zr–Pt zwitterionic heterodimetallic complex. The reaction involves intramolecular migration of two chlorine atoms from Pt to Zr as well as that of a Ph 2 PN i Pr moiety from Zr to Pt.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)