Isolable 1-Butene Copper(I) Complexes and 1-Butene/Butane Separation Using Structurally Adaptable Copper Pyrazolates

Non-porous small molecule adsorbents such as {[3,5-(CF3)(2)Pz]Cu}(3) (where Pz=pyrazolate) are an emerging class of materials that display attractive features for ethene-ethane separation. This work examines the chemistry of fluorinated copper(I) pyrazolates {[3,5-(CF3)(2)Pz]Cu}(3) and {[4-Br-3,5-(CF3)(2)Pz]Cu}(3) with much larger 1-butene in both solution and solid state, and reports the isolation of rare 1-butene complexes of copper(I), {[3,5-(CF3)(2)Pz]Cu(H2C=CHC2H5)}(2) and {[4-Br-3,5-(CF3)(2)Pz]Cu(H2C=CHC2H5)}(2) and their structural, spectroscopic, and computational data. The copper-butene adduct formation in solution involves olefin-induced structural transformation of trinuclear copper(I) pyrazolates to dinuclear mixed-ligand systems. Remarkably, larger 1-butene is able to penetrate the dense solid material and to coordinate with copper(I) ions at high molar occupancy. A comparison to analogous ethene and propene complexes of copper(I) is also provided.

Automated summary

This study examines the chemistry of fluorinated copper(I) pyrazolates with 1-butene, reporting the isolation of rare 1-butene complexes of copper(I) and their structural, spectroscopic, and computational data. The formation of copper-butene adducts in solution involves structural transformation of trinuclear copper(I) pyrazolates to dinuclear mixed-ligand systems, and 1-butene can penetrate dense solid material to coordinate with copper(I) ions. The study also provides a comparison to ethene and propene complexes of copper(I).