BUSCADOR RECOLECTA

The divergent reactivity of the cationic iridium complex [(η5-C5Me5)IrCl(PMe2ArDipp2)]+ (ArDipp2 = C6H3-2,6-(C6H3-2,6-iPr2)2) toward organolithium and Grignard reagents is described. The noninnocent behavior of the Cp* ligand, a robust spectator in the majority of stoichiometric and catalytic reactions, was manifested by its unforeseen electrophilic character toward organolithium reagents LiMe, LiEt, and LinBu. In these unconventional transformations, the metal center is only indirectly involved by means of the Ir(III)/Ir(I) redox cycle. In the presence of less nucleophilic organolithium reagents, the Cp* ligand also exhibits noninnocent behavior undergoing facile deprotonation, which is also concomitant with the reduction of the metal center. In turn, the weaker alkylating agents EtMgBr and MeMgBr effectively achieve the alkylation of the metal center. These reactive iridium(III) alkyls partake in subsequent reactions: while the ethyl complex undergoes β-H elimination, the methyl derivative releases methane by a remote C-H bond activation. Computational studies, including the quantum theory of atoms in molecules (QTAIM), support that the preferential activation of the non-benzylic C-H bonds takes place via sigma-bond metathesis., European Research Council 756575, Ministerio de Ciencia e Innovación PID2019-110856GA-I00, Junta de Andalucía P18-FR-4688, US-1380849, DOC_00153

The divergent reactivity of the cationic iridium complex [(η5-C5Me5)IrCl(PMe2ArDipp2)]+ (ArDipp2 = C6H3-2,6-(C6H3-2,6-iPr2)2) toward organolithium and Grignard reagents is described. The noninnocent behavior of the Cp* ligand, a robust spectator in the majority of stoichiometric and catalytic reactions, was manifested by its unforeseen electrophilic character toward organolithium reagents LiMe, LiEt, and LinBu. In these unconventional transformations, the metal center is only indirectly involved by means of the Ir(III)/Ir(I) redox cycle. In the presence of less nucleophilic organolithium reagents, the Cp* ligand also exhibits noninnocent behavior undergoing facile deprotonation, which is also concomitant with the reduction of the metal center. In turn, the weaker alkylating agents EtMgBr and MeMgBr effectively achieve the alkylation of the metal center. These reactive iridium(III) alkyls partake in subsequent reactions: while the ethyl complex undergoes β-H elimination, the methyl derivative releases methane by a remote C-H bond activation. Computational studies, including the quantum theory of atoms in molecules (QTAIM), support that the preferential activation of the non-benzylic C-H bonds takes place via sigma-bond metathesis., This work has been supported by the European Research Council (ERC Starting Grant, CoopCat, 756575). We also thank Grant PID2019-110856GA-I00 funded by MCIN/AEI/ 10.13039/501100011033, Junta de Andalucía (P18-FR-4688) and US/JUNTA/FEDER, UE (US-1380849). J.J.M. thanks Junta de Andalucía for the postdoctoral program “Personal Investigador Doctor” (ref. DOC_00153). The authors gratefully acknowledge the financial support provided by the Consejo Superior de Investigaciones Científicas (studentship JAEINT_21_00695 granted to A.P.-M.) and the use of CESGA computational facilities., Peer reviewed