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Propylene is a crucial building block to produce many industrial‐scale chemicals including polypropylene. The separation of propylene from propane to reach the high‐purity levels needed for downstream applications is a difficult task due to the close similarities in their physical properties. The olefin/paraffin separation including that involving propylene mainly relies on highly energy‐intensive distillation processes and accounts for nearly 0.3% of the global energy consumption. The utility of a copper complex supported by a fluorinated bis(pyrazolyl)borate is demonstrated to accomplish the separation of propylene from propane repeatedly, under mild conditions with high selectivity. Complete characterization of a rare, copper(I) propylene complex is also reported including the molecular structure.

 

The copper(I), silver(I), and gold(I) metals bind π‐ligands by σ‐bonding and π‐back bonding interactions. These interactions were investigated using bidentate ancillary ligands with electron donating and withdrawing substituents. The π‐ligands span from ethylene to larger terminal and internal alkenes and alkynes. Results of X‐ray crystallography, NMR, and IR spectroscopy and gas phase experiments show that the binding energies increase in the order Ag 

A series of DOSY experiments have been carried out to determine the solution stoichiometry of silver(I) 3,5‐bis (trifluoromethyl)pyrazolate species. This compound exists as a trimer in the solid state (n = 3) but in solutions of chlorinated solvents, the DOSY data suggest the presence of a mixture of solvent stabilized monomer (n = 1) and dimer (n = 2) in equilibrium. Different approximations have been used including the Stokes–Einstein and the Stokes–Einstein–Gierer–Wirtz equations. Some methodological problems are discussed.

 

Purification of C₂H₄from an C₂H₄/C₂H₆mixture is one of the most challenging separation processes, which is achieved mainly through energy‐intensive, cryogenic distillation in industry. Sustainable, non‐distillation methods are highly desired as alternatives. We discovered that the fluorinated bis(pyrazolyl)borate ligand supported copper(I) complex {[(CF₃)₂Bp]Cu}₃has features very desirable in an olefin–paraffin separation material. It binds ethylene exclusively over ethane generating [(CF₃)₂Bp]Cu(C₂H₄). This molecular compound exhibits extremely high and record ideal adsorbed solution theory (IAST) C₂H₄/C₂H₆gas separation selectivity, affording high purity (>99.5 %) ethylene that can be readily desorbed from separation columns. In‐situ PXRD provides a “live” picture of the reversible conversion between [(CF₃)₂Bp]Cu(C₂H₄) and the ethylene‐free sorbent in the solid‐state, driven by the presence or removal of C₂H₄. Molecular structures of trinuclear {[(CF₃)₂Bp]Cu}₃and mononuclear [(CF₃)₂Bp]Cu(C₂H₄) are also presented.

 

Non‐porous small molecule adsorbents such as {[3,5‐(CF₃)₂Pz]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)₂Pz]Cu}₃and {[4‐Br‐3,5‐(CF₃)₂Pz]Cu}₃with 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)₂Pz]Cu(H₂C=CHC₂H₅)}₂and {[4‐Br‐3,5‐(CF₃)₂Pz]Cu(H₂C=CHC₂H₅)}₂and 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.

 

Described herein are the synthesis, structure, and photophysics of the iodo-substituted cyclic trinuclear copper( i ) complex, Cu 3 [4-I-3,5-(CF 3 ) 2 Pz] 3 supported by a highly-fluorinated pyrazolate in comparison with its previously reported 4-Br/4-Cl analogues. The crystal structure is stabilised by multiple supramolecular interactions of Cu 3 ⋯I and hydrogen/halogen bonding. The photophysical properties and supramolecular interactions are investigated experimentally/computationally for all three 4-halo complexes vis-à-vis relativistic effects. 

A useful ligand involving three pyridyl donor arms and fluorocarbon substituents surrounding the coordination pocket has been assembled and utilized in coinage metal chemistry. This tris(pyridyl)borate serves as an excellent ligand support for the stabilization of ethylene complexes of copper, silver and gold.