RESUMO
The trinuclear copper(I) pyrazolate complex [Cu3 ] rearranges to the dinuclear analogue [Cu2 â (C2 H4 )2 ] when exposed to ethylene gas. Remarkably, the [Cu3 ]â[Cu2 â (C2 H4 )2 ] rearrangement occurs reversibly in the solid state. Furthermore, this transformation emulates solution chemistry. The bond-making and breaking processes associated with the rearrangement in the solid-state result in an observed heat of adsorption (-13±1â kJ mol-1 per Cu-C2 H4 interaction) significantly lower than other Cu-C2 H4 interactions (≥-24â kJ mol-1 ). The low overall heat of adsorption, "step" isotherms, high ethylene capacity (2.76â mmol g-1 ; 7.6â wt % at 293â K), and high ethylene/ethane selectivity (136:1 at 293â K) make [Cu3 ] an interesting basis for the rational design of materials for low-energy ethylene/ethane separations.