skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: A Molecular Compound for Highly Selective Purification of Ethylene
Abstract 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.  more » « less
Award ID(s):
1954456
PAR ID:
10302665
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Angewandte Chemie International Edition
Volume:
60
Issue:
52
ISSN:
1433-7851
Page Range / eLocation ID:
p. 27184-27188
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; (, ChemPlusChem)
    Abstract 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. 
    more » « less
  2. ; ; ; (, Advanced Materials)
    Abstract Currently, few porous vanadium metal‐organic frameworks (V‐MOFs) are known and even fewer are obtainable as single crystals, resulting in limited information on their structures and properties. Here this work demonstrates remarkable promise of V‐MOFs by presenting an extensible family of V‐MOFs with tailorable pore geometry and properties. The synthesis leverages inter‐modular synergy on a tri‐modular pore‐partitioned platform. New V‐MOFs show a broad range of structural features and sorption properties suitable for gas storage and separation applications for C2H2/CO2, C2H6/C2H4, and C3H8/C3H6. Thec/aratio of the hexagonal cell, a measure of pore shape, is tunable from 0.612 to 1.258. Other tunable properties include pore size from 5.0 to 10.9 Å and surface area from 820 to 2964 m2g−1. With C2H2/CO2selectivity from 3.3 to 11 and high uptake capacity for C2H2from 65.2 to 182 cm3g−1(298K, 1 bar), an efficient separation is confirmed by breakthrough experiments. The near‐record high uptake for C2H6(166.8 cm3g−1) contributes to the promise for C2H6‐selective separation of C2H6/C2H4. The multi‐module pore expansion enables transition from C3H6‐selective to more desirable C3H8‐selective separation with extraordinarily high C3H8uptake (254.9 cm3g−1) and high separation potential (1.25 mmol g−1) for C3H8/C3H6(50:50 v/v) mixture. 
    more » « less
  3. ; ; ; ; (, Small)
    Abstract Isoreticular chemistry is among the most powerful strategies for designing novel materials with optimizable pore geometry and properties. Of great significance to the further advance of isoreticular chemistry is the development of broadly applicable new concepts capable of guiding and systematizing the ligand‐family expansion as well as establishing correlations between dissimilar and seemingly uncorrelated ligands for better predictive synthetic design and more insightful structure and property analysis. Here ligand circuit concept is proposed and its use has been demonstrated for the synthesis of a family of highly stable, high‐performance pore‐space‐partitioned materials based on an acyclic ligand,trans,trans‐muconic acid. This work represents a key step toward developing highly porous and highly stable pore‐space‐partitioned materials from acyclic ligands. The new materials exhibit excellent sorption properties such as high uptake capacity for CO2(81.3 cm3 g−1) and C2H2(165.4 cm3 g−1) by CPM‐7.3a‐NiV. CPM‐7.3a‐CoV shows C2H6‐selective C2H6/C2H4separation properties and its high uptakes for C2H4(134.0 cm3 g−1) and C2H6(148.0 cm3 g−1) at 1 bar and 298 K contribute to the separation potential of 1.35 mmol g−1. The multi‐cycle breakthrough experiment confirms the promising separation performance for C2H2/CO2. 
    more » « less
  4. ; ; ; ; (, The Journal of Chemical Physics)
    Helium droplets are unique hosts for isolating diverse molecular ions for infrared spectroscopic experiments. Recently, it was found that electron impact ionization of ethylene clusters embedded in helium droplets produces diverse carbocations containing three and four carbon atoms, indicating effective ion–molecule reactions. In this work, similar experiments are reported but with the saturated hydrocarbon precursor of ethane. In distinction to ethylene, no characteristic bands of larger covalently bound carbocations were found, indicating inefficient ion–molecule reactions. Instead, the ionization in helium droplets leads to formation of weaker bound dimers, such as (C2H6)(C2H4)+, (C2H6)(C2H5)+, and (C2H6)(C2H6)+, as well as larger clusters containing several ethane molecules attached to C2H4+, C2H5+, and C2H6+ionic cores. The spectra of larger clusters resemble those for neutral, neat ethane clusters. This work shows the utility of the helium droplets to study small ionic clusters at ultra-low temperatures. 
    more » « less
  5. ; ; ; ; ; ; (, Angewandte Chemie International Edition)
    Abstract We report copper(II) and copper(III) trifluoromethyl complexes supported by a pyridinedicarboxamide ligand (L) as a platform for investigating the role of electron transfer in C(sp2)−H trifluoromethylation. While the copper(II) trifluoromethyl complex is unreactive towards (hetero)arenes, the formal copper(III) trifluoromethyl complex performs C(sp2)−H trifluoromethylation of a wide range of (hetero)arenes. Mechanistic studies using the copper(III) trifluoromethyl complex suggest that the mechanism of arene trifluoromethylation is substrate‐dependent. When the thermodynamic driving force for electron transfer is high, the reaction proceeds through a previously unidentified single electron transfer (SET) mechanism, where an initial electron transfer occurs between the substrate and oxidant prior to CF3group transfer. Otherwise, a CF3radical release/electrophilic aromatic substitution (SEAr) mechanism is followed. These studies provide valuable insights into the role of strong oxidants and potential mechanistic dichotomy in Cu‐mediated C(sp2)−H trifluoromethylation. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email