Gold nanoparticles stabilized by phosphine-decorated polymer immobilized ionic liquids (AuNP@PPh2-PIILP) is an extremely efficient multiproduct selective catalyst for the sodium borohydride-mediated reduction of nitrobenzene giving N-phenylhydroxylamine, azoxybenzene, or aniline as the sole product under mild conditions and a very low catalyst loading. The use of a single nanoparticle-based catalyst for the partial and complete reduction of nitroarenes to afford three different products with exceptionally high selectivities is unprecedented. Under optimum conditions, thermodynamically unfavorable N-phenylhydroxylamine can be obtained as the sole product in near quantitative yield in water, whereas a change in reaction solvent to ethanol results in a dramatic switch in selectivity to afford azoxybenzene. The key to obtaining such a high selectivity for N-phenylhydroxylamine is the use of a nitrogen atmosphere at room temperature as reactions conducted under an inert atmosphere occur via the direct pathway and are essentially irreversible, while reactions in air afford significant amounts of azoxy-based products by virtue of competing condensation due to reversible formation of N-phenylhydroxylamine. Ultimately, aniline can also be obtained quantitatively and selectively by adjusting the reaction temperature and time accordingly. Introduction of PEG onto the polyionic liquid resulted in a dramatic improvement in catalyst efficiency such that N-phenylhydroxylamine could be obtained with a turnover number (TON) of 100 000 (turnover frequency (TOF) of 73 000 h–1, with >99% selectivity), azoxybenzene with a TON of 55 000 (TOF of 37 000 h–1 with 100% selectivity), and aniline with a TON of 500 000 (TOF of 62 500 h–1, with 100% selectivity). As the combination of ionic liquid and phosphine is required to achieve high activity and selectivity, further studies are currently underway to explore whether interfacial electronic effects influence adsorption and thereby selectivity and whether channeling of the substrate by the electrostatic potential around the AuNPs is responsible for the high activity. This is the first report of a AuNP-based system that can selectively reduce nitroarenes to either of two synthetically important intermediates as well as aniline and, in this regard, is an exciting discovery that will form the basis to develop a continuous flow process enabling facile scale-up.

Palladium nanoparticles stabilized by heteroatom donor-modified polystyrene-based polymer immobilized ionic liquids (PdNP@HAD-PIILP; HAD-PPh 2 , OMe, NH 2 , CN, pyrrolidone) are highly efficient catalysts for the Suzuki-Miyaura cross-coupling in aqueous media under mild conditions. Catalyst modified with phosphine was consistently the most efficient as it gave high yields across a range of substrates under mild conditions at low catalyst loadings. Incorporation of polyethylene glycol into the phosphine modified immobilised ionic liquid support improved catalyst efficacy by improving dispersibility and facilitating access to the active site. Moreover, each of the heteroatom modified catalysts was more active than the corresponding unsubstituted imidazolium-based polystyrene benchmark as well as commercial samples of Pd/ C. Catalyst generated in situ from either [PdCl 4 ]@PPh 2 -PIILP or its PEGylated counterpart [PdCl 4 ]@PPh 2 -PEGPIILP, by reduction with phenylboronic acid, outperformed their pre-formed counterparts for the vast majority of substrates examined. The turnover frequency of 16,300 h À1 obtained at room temperature is one of the highest to be reported for palladium nanoparticle-catalysed Suzuki-Miyaura cross-coupling between 4bromoacetophenone and phenylboronic acid in aqueous media under such mild conditions.

Phosphino-decorated polymer immobilised ionic liquid-stabilised PdNPs are highly efficient catalysts for the aqueous phase hydrogenation and transfer hydrogenation of aromatic nitro compounds in batch and continuous flow.

An aqueous phase hydrogenation of α,β-unsaturated aldehydes with remarkable selectivity for the CC double bond under mild conditions.

A simple and operationally practical method to sequester and remove fluoride generated through the S N Ar reaction between amines and aryl fluorides is reported. Calcium propionate acts as an inexpensive and environmentally benign in situ scrubber of the hydrofluoric acid byproduct, which is simply precipitated and filtered from the reaction mixture during standard aqueous workup. The method has been tested from 10 to 100 g scale of operation, showing >99.5% decrease in fluoride content in each case. Full mass recovery of calcium fluoride is demonstrated at both scales, proving this to be a general, efficient, and robust method of fluoride abstraction to help prevent corrosion of glass-lined reactors.