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Synthesis and reduction chemistry of mixed-Lewis-base-stabilised chloroborylenes.

ABSTRACT: The one-electron reduction of (CAAC^Me)BCl₃ (CAAC^Me = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) yields the dichloroboryl radical [(CAAC^Me)BCl₂]˙. Furthermore, the twofold reduction of (CAAC^Me)BCl₃ in the presence of a range of Lewis bases (L = CAAC^Me, N-heterocyclic carbene, phosphine) yields a series of doubly base-supported (CAAC^Me)LBCl chloroborylenes, all of which were structurally characterised. NMR and UV-vis spectroscopic and electrochemical data for (CAAC^Me)LBCl show that the boron centre becomes more electron-rich and the HOMO-LUMO gap widens as L becomes less π-accepting. A [(CAAC^Me)BCl₂]^- boryl anion coordination polymer was isolated as a potential intermediate in these reductions. In most cases the reduction of the chloroborylenes resulted in the formation of the corresponding hydroborylenes or derivatives thereof, as well as ligand C-H activation products.

SUBMITTER: Arrowsmith M

PROVIDER: S-EPMC6531816 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature

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Synthesis and reduction chemistry of mixed-Lewis-base-stabilised chloroborylenes.

Arrowsmith Merle M Schweizer Julia I JI Heinz Myron M Härterich Marcel M Krummenacher Ivo I Holthausen Max C MC Braunschweig Holger H

Chemical science 20190408 19

The one-electron reduction of (CAACMe)BCl3 (CAACMe = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) yields the dichloroboryl radical [(CAACMe)BCl2]˙. Furthermore, the twofold reduction of (CAACMe)BCl3 in the presence of a range of Lewis bases (L = CAACMe, N-heterocyclic carbene, phosphine) yields a series of doubly base-supported (CAACMe)LBCl chloroborylenes, all of which were s ...[more]

PMID: 31183061

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