Photocatalyzed borylation using water-soluble quantum dots

Abstract

Herein, we report the use of water-soluble MPA-capped quantum dot (QD) photocatalysts for the borylation of diazonium salts in the presence of water.

New avenues for C–B bond formationviaradical intermediates

“…19 Moreover, Maiti used water soluble CdSe-quantum dots as redox catalysts (or smart initiators) for the radical borylation of diazonium salts with diboron esters in biphasic CH 2 Cl 2 /H 2 O under blue LED irradiation. 20 Diazonium salts were found to readily react with various metallocenes (Ti, Zr, Co, Ni, Ru) employing H 2 B]NiPr 2 as boron source to provide the corresponding aryl amino boranes, which were further converted to the pinacol boronic esters prior to isolation, as reported by Pucheault (Scheme 2b). 21 The authors suggested a radical chain reaction initiated by an ET from the metallocene Cp 2 M to the diazonium salt.…”

Release of Warfarin from Human Serum Albumin by Water‐soluble CdSe Nanotetrapods

“…[66] However, water soluble MPA-capped nanotetrapods are non-emissive ( Figure S3), in contrast to organic-soluble oleic acid capped ones [10,11] as well as water-soluble spherical quantum dots, which are usually photoluminescent. [38,39] Nonemissive nature of water-soluble nanotetrapods may be ascribed to incomplete passivation of their surface dangling bonds, due to their anisotropic three dimensional structure. It may be recalled here that PL quantum yield for organic-soluble oleic acid capped are significantly lower than that for spherical quantum dots, most likely for the same reason.…”

“…[35][36][37] Water solubility of nanocrystals is a key requirement in their biological applications and catalysis in aqueous medium. [38][39][40] They find application in sensing analytes in aqueous medium. [41][42][43] Bright and stable water soluble QDs can be prepared by deposition of a monolayer of silane on QDs.…”

Photocatalytic C–X borylation of aryl halides by hierarchical SiC nanowire-supported Pd nanoparticles

“…Moreover, electron-rich active sites in catalysts can accelerate the activation of C-halogen bonds; hence, there is considerable interest in employing light irradiation as an alternative approach to increase the electron density at active sites and promote the reactions involving aryl halides. Recently, Chandrashekar et al [48] reported the photocatalytic transformation of diazonium salts to arylboronates with high turnover number in the presence of water-soluble 3-mercaptopropionic acid (MPA)-capped, CdSe-based quantum dots. The CdSe dots transfer excited-state electrons to the substrate to form aryl radicals, which react with the borylating agent to form the arylboronate.…”