Structurally versatile phosphine and amine donors constructed from N-heterocyclic olefin units

Abstract

A general strategy for the synthesis of hindered N- and P-based donors is presented whereby the strongly electron releasing N-heterocyclic olefin (NHO) unit, IPrCH-, (IPrCH- = [(HCNDipp)2CCH]-; Dipp = 3,6-iPr2C6H2) is linked to terminally bound phosphine and amine donors. Preliminary coordination chemistry is presented involving phosphine (IPrCH)PR2 (R = iPr and Ph) and amine (IPrCH)NMe2 ligands and the Lewis acids BH3 and AuCl. Interestingly, (IPrCH)NMe2 binds AuCl through an exocyclic olefin unit, while the softer phosphorus centers in (IPrCH)PR2 coordinate to yield Au-P linkages; thus the reported NHO-based ligands exhibit tunable binding modes to metals.