On the Reaction Mechanism of the Rhodium-Catalyzed Arylation of Fullerene (C60) with Organoboron Compounds in the Presence of Water

Abstract

Density functional theory (DFT) calculations were carried out to study the reaction mechanism of the Suzuki–Miyaura rhodium-catalyzed hydroarylation of fullerene (C60) by phenylboronic acid in the presence of water. As found experimentally, our results confirm that addition of the phenyl group and the hydrogen atom in C60 occurs at the [6,6] bond. The rate-determining step corresponds to the simultaneous transfer of a hydrogen atom from a water molecule to C60 and the recovery of the active species. The use of 2-phenyl-1,3,2-dioxaborinane and the 4,4,5,5-tetramethyl-2-phenyl-1,3,2,-dioxaborolane instead of phenylboronic acid as organoborate agents does not lead to great modifications of the energy profile. The possible higher steric hindrance of 4,4,5,5-tetramethyl-2-phenyl-1,3,2,-dioxaborolane should not inhibit its use in the hydroarylation of C60. Overall, we show how organoboron species arylate C60 in rhodium-based catalysis assisted by water as a source of protonsA.P. thanks the Spanish Ministry of Economy and Competitiveness (MINECO) for a Ramûn y Cajal contract (RYC-2009-05226) and grant no. CTQ2014-59832-JIN, and a European Commission Career Integration Grant (CIG09-GA-2011-293900). J.P.M. gratefully acknowledges a Ph.D. fellowship (register/application no. 217067/312543) from the Mexican National Council of Science and Technology (CONACYT). M.S. acknowledges funding through a European Union (EU) FEDER fund (UNGI08-4E-003 and UNGI10-4E-801), the Generalitat de Catalunya (Spain) (project 2014SGR931), a Catalan Institution for Research and Advanced Studies (ICREA) Academia prize (2014), and MINECO project CTQ2014-54306-