Frustrated Lewis pair

In chemistry, a frustrated Lewis pair (FLP) is a compound or mixture containing a Lewis acid and a Lewis base that, because of steric hindrance, cannot combine to form a classical adduct. Many kinds of FLPs have been devised, and many simple substrates exhibit activation. In chemistry, a frustrated Lewis pair (FLP) is a compound or mixture containing a Lewis acid and a Lewis base that, because of steric hindrance, cannot combine to form a classical adduct. Many kinds of FLPs have been devised, and many simple substrates exhibit activation. The discovery that some FLPs split H2 triggered a rapid growth of research into FLPs. Because of their 'unquenched' reactivity, such systems are reactive toward substrates that can undergo heterolysis. For example, many FLPs split hydrogen molecule. Thus, a mixture of tricyclohexylphosphine (PCy3) and tris(pentafluorophenyl)borane reacts with hydrogen to give the respective phosphonium and borate ions: This reactivity has been exploited to produce FLPs which catalyse hydrogenation reactions.