Microfluidic Investigations of CO2 and H2 Activation by Lewis Pairs

A microfluidic strategy has been used for the time- and labour-efficient evaluation of the relative efficiency and thermodynamic parameters of CO2 binding by three Lewis acid/base combinations, where efficiency is based on the amount of CO2 taken up per binding unit in solution. Neither tBu3P nor B(C6F5) 3 were independently effective at CO2 capture, and the combination of the imidazolin-2-ylidenamino-substituted phosphine (NIiPr) 3P and B(C6F5)3 was equally ineffective. Nonetheless, an archetypal frustrated Lewis pair (FLP) comprised of tBu3P and B(C6F5)3 was shown to bind CO2 more efficiently than either the FLP derived from 2,2,6,6-tetramethylpiperidine (TMP) and B(C6F5) 3 or the highly basic phosphine (NIiPr)3P. Moreover, the proposed microfluidic platform was used to elucidate the thermodynamic parameters for these reactions. This microfluidic approach was also applied to obtain thermodynamic parameters for H2 activation by the FLP comprised of tBu3P and B(C6F5 )3 with subsequent kinetic studies underway.