Modulating the σ-Accepting Properties of an Antimony Z-type Ligand via Anion Abstraction: Remote-Controlled Reactivity of the Coordinated Platinum Atom.

In search of ligand platforms, which can be used to remotely control the catalytic activity of a transition metal, we have investigated the coordination noninnocence of ambiphilic L/Z-type ligands containing a trifluorostiborane unit as a Lewis acid. The known dichlorostiboranyl platinum complex (( o-(PhP)CH)SbCl)PtCl (1) reacts with TlF in the presence of acetonitrile (MeCN) and cyclohexyl isocyanide (CyNC) to afford the trifluorostiborane platinum complexes 2 ((( o-(PhP)CH)SbF)Pt-NCMe) and 3 ((( o-(PhP)CH)SbF)Pt-CNCy), respectively. Formation of these complexes, which results from a redistribution of the halide ligands about the dinuclear core, affects the nature of the Pt-Sb bond.

An ambiphilic phosphine/H-bond donor ligand and its application to the gold mediated cyclization of propargylamides.

We describe the synthesis of an ambiphilic phosphine/H-bond donor ligand featuring a trifluoroacetamide functionality, its coordination to gold(i) chloride, and its application as a self-activating catalyst for the cyclization of propargylamides.

Anion-Controlled Positional Switching of a Phenyl Group about the Dinuclear Core of a AuSb Complex.

As part of our continuing interest in redox-active, anion-responsive main-group transition-metal platforms, we have investigated the effect of chloride by fluoride anion substitution on the core structure of a dinuclear AuSb platform. Starting from [(o-(iPr2P)C6H4)2Cl2SbPh]AuCl (2) in which the antimony-bound phenyl group is positioned trans to the gold atom, we found that the introduction of fluoride anions, as in [(o-(iPr2P)C6H4)2F2SbPh]AuCl (3) and [(o-(iPr2P)C6H4)2ClFSbPh]AuCl (4), produces structures in which the phenyl group switches to a perpendicular direction with respect to the gold atom. Replacement of the gold-bound chloride anion in 3 by a fluoride anion can be achieved by successive treatment with TlPF6 and [nBu4N][Ph3SiF2].