Design of CO2 hydrogenation catalysts based on phosphane/borane frustrated Lewis pairs and xanthene-derived scaffolds

UK Catalysis Hub is kindly thanked for resources and support provided via our membership of the UK Catalysis Hub Consortium and funded by EPSRC grant: EP/R026939/1, EP/R026815/1, EP/R026645/1, EP/R027129/1, and EP/M013219/1. J.W.M.C. acknowledges financial support from FAPERJ (grants E-26/203.001/2017, E-26/010.101118/2018, and E-26010.001424/2019) and CNPq (grants 309080/2015-0 and 434955/2018-3). M.B. thanks the School of Chemistry in St Andrews and EaStCHEM for support.New naphtho[2,1,8,7-klmn]xanthene and benzo[kl]xanthene-based intramolecular phosphane–borane frustrated Lewis pairs (FLPs) were investigated in catalyzed H2 activation and CO2 hydrogenation processes. According to DFT predictions at the B3LYP-D3 level, the presence of rigid scaffolds and increased P···B distances in the investigated FLPs lead to a remarkable drop in the energy barrier for CO2 hydrogenation (by up to 19.2 kcal mol−1, compared to the parent dimethylxanthene-based FLP). Furthermore, the energy differences between the transition states for H2 activation and CO2 hydrogenation are significantly reduced, making both processes feasible under relatively mild experimental conditions.Publisher PDFPeer reviewe