H2 evolution from H2O via O-H oxidative addition across a 9,10-diboraanthracene

Jordan W Taylor; W Hill Harman

doi:10.1039/d0cc05261b

H₂ evolution from H₂O via O-H oxidative addition across a 9,10-diboraanthracene

Chem Commun (Camb). 2020 Nov 18;56(89):13804-13807. doi: 10.1039/d0cc05261b. Epub 2020 Oct 20.

Authors

Jordan W Taylor¹, W Hill Harman

Affiliation

¹ Department of Chemistry, University of California, Riverside, Riverside, CA 92521, USA. hill.harman@ucr.edu.

PMID: 33078792
DOI: 10.1039/d0cc05261b

Abstract

The water reactivity of the boroauride complex ([Au(B₂P₂)][K(18-c-6)]; (B₂P₂, 9,10-bis(2-(diisopropylphosphino)-phenyl)-9,10-dihydroboranthrene) and its corresponding two-electron oxidized complex, Au(B₂P₂)Cl, are presented. Au(B₂P₂)Cl is tolerant to H₂O and forms the hydroxide complex Au(B₂P₂)OH in the presence of H₂O and triethylamine. [Au(B₂P₂)]Cl and [Au(B₂P₂)]OH are poor Lewis acids as judged by the Gutmann-Becket method, with [Au(B₂P₂)]OH displaying facile hydroxide exchange between B atoms of the DBA ring as evidenced by variable temperature NMR spectroscopy. The reduced boroauride complex [Au(B₂P₂)]^- reacts with 1 equivalent of H₂O to produce a hydride/hydroxide product, [Au(B₂P₂)(H)(OH)]^-, that rapidly evolves H₂ upon further H₂O reaction to yield the dihydroxide compound, [Au(B₂P₂)(OH)₂]^-. [Au(B₂P₂)]Cl can be regenerated from [Au(B₂P₂)(OH)₂]^-via HCl·Et₂O, providing a synthetic cycle for H₂ evolution from H₂O enabled by O-H oxidative addition at a diboraanthracene unit.