Hydroboration of carbon dioxide with catechol- and pinacolborane using an Ir–CNP* pincer complex. Water influence on the catalytic activity

Description

Iridium complexes based on deprotonated lutidine-derived CNP* pincers 2a/2b selectively catalyzed the hydroboration of CO2 under mild conditions (1–2 bar CO2, 30 °C) to methoxyborane using HBcat (TOF up to 56 h−1 ) and to the formate level with HBpin (TOF up to 1245 h−1 ). Interestingly, an intriguing, positive water effect on the reaction rates has been observed. NMR spectroscopy and ESI-MS analysis of the hydroboration reactions have shown the formation of ligand-protonated [Ir(CNP)(CO)(BR2)H][B(R2)2] (R2 = catecholate, pinacolate) derivatives under catalytic conditions. Control experiments, however, have demonstrated that these derivatives are not catalytically competent species in the hydroboration of CO2.

Abstract

Ministerio de Economía y Competitividad de España (MINECO) y fondos FEDER de la Unión Europea-CTQ2016-80814-R y CTQ2016-81797-REDC

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