  Nowadays, hydrogen activation by frustrated Lewis pairs (FLPs) and their
applications have been demonstrated to be one of emerge research topics in the
field of catalysis. Previous studies have shown that the thermodynamics of
these reaction is determined by electronic structures of FLPs and solvents.
Herein, we investigated the systems consisting of typical FLPs and ionic
liquids (ILs), which are well known by their large number of types and
excellent solvent effects. The density functional theory (DFT) calculations
were performed to study the thermodynamics for H2 activation by both inter- and
intra-molecular FLPs, as well as the individual components. The results show
that the computed overall Gibbs free energies in ILs are more negative than
that computed in toluene. Through the thermodynamics partitioning, we find that
ILs favor the H-H cleavage elemental step, while disfavored the elemental steps
of proton attachment, hydride attachment and zwitterionic stabilization.
Moreover, the results show that these effects are strongly dependent on the
type of FLPs, where intra-molecular FLPs are more effected compared to the
inter-molecular FLPs.
