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

Abstract

AbstractTreatment of ZrCl4 with 3 equiv. of Li(PPh2NR) (R = tBu, iPr) gives tris(phosphinoamide)zirconium complexes, (PPh2NR)3ZrCl [R = tBu (1a), iPr (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(Ph2PNR)3ZrCl [R = tBu (2a), iPr (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)3Mo(Ph2PNiPr)3ZrCl (3), is synthesized from 1b and Mo(CO)3(CH3CN)3, in which the ligands around the Mo center are arranged octahedrally, and three phosphorus moieties are coordinated in the fac‐P3 fashion. The reaction of 1b with a square planar PtII precursor, such as (COD)PtCl2, is unique and gives (κ2‐Ph2PNiPr)Pt(Ph2PNiPr)2ZrCl3 (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 Ph2PNiPr moiety from Zr to Pt.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)