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The first definitive examples of cyclodiphosphinophosphonium and cyclotriphosphinophosphonium cations that represent new prototypical frameworks in the rational and systematic development of catena-phosphorus chemistry are described. Addition of methyl triflate or triflic acid to cyclotetraphosphines predictably gives cyclotriphosphinophosphonium salts.

Al[X.sub.3] (X = Cl or Br) and P[Mes.sub.3] (Mes = 2,4,6-[C.sub.6][H.sub.2][Me.sub.3]) have reacted to form weak Lewis adducts and have also reacted with C[O.sub.2] to give [Mes.sub.3]P(C[O.sub.2])[(Al[X.sub.3]).sub.2] (X = Cl; Br). The species have reacted with excess ammonia borane at room temperature to produce C[H.sub.3]OH upon quenching with water.

Frustrated Lewis pairs (FLPs) comprising sterically hindered Lewis acids and bases offer the capability to reversibly capture CO2 under mild reaction conditions. The determination of equilibrium constants and thermodynamic properties of these reactions should enable assessment of the efficiency of a particular FLP system for CO2 sequestration and provide insights for design of new, efficient formulations of FLP catalysts for CO2 capture. We have developed a microfluidic approach to studies of FLP-CO2 reactions, which provides their thermodynamic characterization that is not accessible otherwise. The approach enables the determination of the equilibrium reaction constants at different temperatures, the enthalpy, the entropy, and the Gibbs energy of these reactions, as well as the enhancement factor. The microfluidic methodology has been validated by applying it to the well-characterized reaction of CO2 with a secondary amine. The microfluidic approach can be applied for fundamental thermodynamic studies of other gas-liquid reactions.