Search for: All records

Solvents are the major source of chemical waste from synthetic chemistry labs. Growing attention to more environmentally friendly sustainable processes demands novel technologies to substitute toxic or hazardous solvents. If not always, sometimes, water can be a suitable substitute for organic solvents, if used appropriately. However, the sole use of water as a solvent remains non-practical due to its incompatibility with organic reagents. Nonetheless, over the past few years, new additives have been disclosed to achieve chemistry in water that also include aqueous micelles as nanoreactors. Although one cannot claim micellar catalysis to be a greener technology for every single transformation, it remains the sustainable or greener alternative for many reactions. Literature precedents support that micellar technology has much more potential than just as a reaction medium, i.e. , the role of the amphiphile as a ligand obviating phosphine ligands in catalysis, the shielding effect of micelles to protect water-sensitive reaction intermediates in catalysis, and the compartmentalization effect. While compiling the powerful impact of micellar catalysis, this article highlights two diverse recent technologies: (i) the design and employment of the surfactant PS-750-M in selective catalysis; (ii) the use of the semisynthetic HPMC polymer to enable ultrafast reactions in water. 

Abstract Herein, we developed the recyclable ligand‐free iridium (Ir)‐hydride based Ir⁰nanoparticles (NPs) for the first regioselective partial hydrogenation of P^V‐substituted naphthalenes. Both the isolated and in situ generated NPs are catalytically active. A control nuclear magnetic resonance (NMR) study revealed the presence of metal‐surface‐bound hydrides, most likely formed from Ir⁰species. A control NMR study confirmed that hexafluoroisopropanol as a solvent was accountable for substrate activation via hydrogen bonding. High‐resolution transmission electron microscopy of the catalyst supports the formation of ultrasmall NPs, and X‐ray photoelectron spectroscopy confirmed the dominance of Ir⁰in the NPs. The catalytic activity of NPs is broad as showcased by highly regioselective aromatic ring reduction in various phosphine oxides or phosphonates. The study also showcased a novel pathway toward preparingbis(diphenylphosphino)‐5,5′,6,6′,7,7′,8,8′‐octahydro‐1,1′‐binaphthyl (H₈‐BINAP) and its derivatives without losing enantioselectivity during catalytic events.