Synthesis and Coordination of a Bisphosphine-[NHC-borane] Compound: A Ligand Framework for Bimetallic Structure Featuring a Boron-Bridging Moiety.

We report herein the synthesis of a bisphosphine-[NHC-BH3] compound and its coordination toward gold. The ligand is shown to support a bimetallic structure bisphosphine-[NHC-BH3](AuCl)2. The abstraction of one chloride from the gold metal center triggers the activation of a BH3 fragment, leading to the reductive elimination of H2 and the formation of a dicationic Au42+ complex featuring Au centers at the +0.5 oxidation state, via a (µ-H)Au2 intermediate, characterized in situ at 183 K. The reactivity of Au4 with thiophenol led to the reoxidation of the gold metal centers to a (µ-S(Ph))Au2 complex. In the different complexes, borane fragment was shown to bridge the Au2 core via weak interaction with [BH], [BCl], and [BH2] moieties.

Ruthenium-NHC complex-catalyzed P(III)-directed C-H borylation of arylphosphines.

(NHC)(arene)Ru(II) complexes with bidentate LX-type NHC-carboxylate ligands were efficiently synthesized and fully characterized including solid-state structures. The strong coordination of the NHC carboxylate ligand and the labile character of the arene ligand are highlighted. These unprecedented Ru(II) complexes demonstrated efficient catalytic activities in the selective P(III)-directed C-H borylation at the ortho position of arylphosphines, representing the first report of the use of a ruthenium-NHC based catalyst in C-H borylation.

A Masked Form of an O-Borylated Breslow Intermediate for the Diastereoselective FLP-Type Activation of Aldehydes.

Breslow intermediates are very often elusive species whose application in frustrated Lewis pair (FLP) chemistry is unprecedented. Described herein is the use of a masked form of an O-borylated Breslow (OBB) intermediate that performs FLP-type activation of the carbonyl function of five different benzaldehyde derivatives with complete diastereoselectivity. The resulting compounds are characterised in solution by NMR spectroscopy (compounds 4-8) and in solid state by X-ray diffraction analysis (compounds 4-6). A combined kinetic and theoretical investigation reveals the associative nature of the rate determining step and suggests that the OBB intermediate part is never released during the whole process.

Copper-Based Hybrid Polyion Complexes for Fenton-Like Reactions.

An innovative strategy allowing the development of a new generation of easy-to-prepare and easy-to-use nano-sized catalysts with high tenability is presented. This strategy is based on the formation of hybrid polyion complexes (HPICs) from the complexation of copper with a block copolymer consisting of an ionizable complexing block and a neutral stabilizer block. These complexes have a well-defined structure and size with a hydrodynamic diameter around 29 nm. They are stable in aqueous solution over a pH range from 4 to 8 and are not sensitive to NaCl salt addition or dilution effects. As a proof-of-concept the degradation of naphthol blue black in water through the use of the Fenton or photo-Fenton reaction is studied. Their performances are comparable to a classical homogeneous reaction, whereas HPICs are easily recyclable by simple dialysis.