On the hydrogen activation by frustrated Lewis pairs in the solid state: benchmark studies and theoretical insights

Abstract

Recently, the concept of small molecule activation by frustrated Lewis pairs (FLPs) has been expanded to the solid state showing a variety of interesting reactivities. Therefore, there is a need to establish a computational protocol to investigate such systems theoretically. In the present study, we selected several FLPs and applied multiple levels of theory, ranging from a semi-empirical tight-binding Hamiltonian to dispersion corrected hybrid density functionals. Their performance is benchmarked for the computation of crystal geometries, thermostatistical contributions, and reaction energies. We show that the computationally efficient HF-3c method gives accurate crystal structures and is numerically stable and sufficiently fast for routine applications. This method also gives reliable values for the thermostatistical contributions to Gibbs free energies. The meta-generalized gradient approximated TPSS-D3 evaluated in a projector augmented plane wave basis set is able to produce sufficiently accurate reaction electronic energies. The established protocol is intended to support experimental studies and to predict new reactions in the emerging field of solid-state FLPs.This article is part of the themed issue 'Frustrated Lewis pair chemistry'.

Reaction mechanism of hydrogen activation by frustrated Lewis pairs

“…Theoretical studies showed that the gas−phase reaction energies (ΔE) are always more negative in solid state than that in both gas and solution phase for the same H2 activation reactions. 73 It is believed that the LA/LB work in a cooperated fashion, in both the formation (Figure 1). The results showed that H2 activation by tBu3P/B(C6F5)3 pair mainly consists of two elementary steps: hydride (H − ) transfer to B and proton (H + ) transfer to P, which is quite consistent with the previous AIMD studies.…”

Frustrated Lewis pair chemistry

“…We begin with a conceptual consideration of the broader context of FLP chemistry by Fontaine & Stephan [1] and then Bullock & Chambers [2] provide an overview of the notion of FLP chemistry across the periodic table. Grimme and co-workers [3] provide a discussion of the theoretical considerations of the quintessential reaction of FLPs, the activation of H 2 , while Erker and co-workers [4] report on the development of FLPs derived from carbon-Lewis bases and boron-Lewis acids. Melen and co-workers [5] discuss reactions of FLPs inspired by biologically relevant systems and Uhl and co-workers [6] describe aluminiumphosphorus based FLPs.…”

Solid state frustrated Lewis pair chemistry

“…We employed a hierarchy of theoretical methods, ranging from semi-empirical tight-binding Hamiltonians to accurate London dispersion corrected hybrid density functionals. 38 – 45 More discussion of methodological points and computational details can be found in our previous benchmark study 46 and in the ESI. † The main representative results of the PCy 3 /B(C 6 F 5 ) 3 FLP are shown in Fig.…”