Browsing by Author "Forgan RS"

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    From Gas Phase Observations to Solid State Reality: The Identification and Isolation of Trinuclear Salicylaldoximato Copper Complexes
    (MDPI (Basel, Switzerland), 2022-09-29) Roach BD; Forgan RS; Kamenetzky E; Parsons S; Plieger PG; White FJ; Woodhouse S; Tasker PA; Morazzoni F
    Conditions have been identified in which phenolic aldoximes and ketoximes of the types used in commercial solvent extraction processes can be doubly deprotonated and generate polynuclear Cu complexes with lower extractant:Cu molar ratios than those found in commercial operations. Electrospray mass spectrometry has provided an insight into the solution speciation in extraction experiments and has identified conditions to allow isolation and characterization of polynuclear Cu-complexes. Elevation of pH is effective in enhancing the formation of trinuclear complexes containing planar {Cu3-μ3-O}4+ or {Cu3-μ3-OH}5+ units. DFT calculations suggest that such trinuclear complexes are more stable than other polynuclear species. Solid structures of complexes formed by a salicylaldoxime with a piperidino substituent ortho to the phenolic OH group (L9H2) contain two trinuclear units in a supramolecular assembly, {[Cu3OH(L9H)3(ClO4)](ClO4)} 2, formed by H-bonding between the central {Cu3-μ3-OH}5+ units and oxygen atoms in the ligands of an adjacent complex. Whilst the lower ligand:Cu molar ratios provide more efficient Cu-loading in solvent extraction processes, the requirement to raise the pH of the aqueous phase to achieve this will make it impractical in most commercial operations because extraction will be accompanied by the precipitation (as oxyhydroxides) of Fe(III) which is present in significant quantities in feed solutions generated by acid leaching of most Cu ores.
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    How Reproducible are Surface Areas Calculated from the BET Equation?
    (Wiley-VCH GmbH, 2022-05-23) Osterrieth JWM; Rampersad J; Madden D; Rampal N; Skoric L; Connolly B; Allendorf MD; Stavila V; Snider JL; Ameloot R; Marreiros J; Ania C; Azevedo D; Vilarrasa-Garcia E; Santos BF; Bu X-H; Chang Z; Bunzen H; Champness NR; Griffin SL; Chen B; Lin R-B; Coasne B; Cohen S; Moreton JC; Colón YJ; Chen L; Clowes R; Coudert F-X; Cui Y; Hou B; D'Alessandro DM; Doheny PW; Dincă M; Sun C; Doonan C; Huxley MT; Evans JD; Falcaro P; Ricco R; Farha O; Idrees KB; Islamoglu T; Feng P; Yang H; Forgan RS; Bara D; Furukawa S; Sanchez E; Gascon J; Telalović S; Ghosh SK; Mukherjee S; Hill MR; Sadiq MM; Horcajada P; Salcedo-Abraira P; Kaneko K; Kukobat R; Kenvin J; Keskin S; Kitagawa S; Otake K-I; Lively RP; DeWitt SJA; Llewellyn P; Lotsch BV; Emmerling ST; Pütz AM; Martí-Gastaldo C; Padial NM; García-Martínez J; Linares N; Maspoch D; Suárez Del Pino JA; Moghadam P; Oktavian R; Morris RE; Wheatley PS; Navarro J; Petit C; Danaci D; Rosseinsky MJ; Katsoulidis AP; Schröder M; Han X; Yang S; Serre C; Mouchaham G; Sholl DS; Thyagarajan R; Siderius D; Snurr RQ; Goncalves RB; Telfer S; Lee SJ; Ting VP; Rowlandson JL; Uemura T; Iiyuka T; van der Veen MA; Rega D; Van Speybroeck V; Rogge SMJ; Lamaire A; Walton KS; Bingel LW; Wuttke S; Andreo J; Yaghi O; Zhang B; Yavuz CT; Nguyen TS; Zamora F; Montoro C; Zhou H; Kirchon A; Fairen-Jimenez D
    Porosity and surface area analysis play a prominent role in modern materials science. At the heart of this sits the Brunauer-Emmett-Teller (BET) theory, which has been a remarkably successful contribution to the field of materials science. The BET method was developed in the 1930s for open surfaces but is now the most widely used metric for the estimation of surface areas of micro- and mesoporous materials. Despite its widespread use, the calculation of BET surface areas causes a spread in reported areas, resulting in reproducibility problems in both academia and industry. To prove this, for this analysis, 18 already-measured raw adsorption isotherms were provided to sixty-one labs, who were asked to calculate the corresponding BET areas. This round-robin exercise resulted in a wide range of values. Here, the reproducibility of BET area determination from identical isotherms is demonstrated to be a largely ignored issue, raising critical concerns over the reliability of reported BET areas. To solve this major issue, a new computational approach to accurately and systematically determine the BET area of nanoporous materials is developed. The software, called "BET surface identification" (BETSI), expands on the well-known Rouquerol criteria and makes an unambiguous BET area assignment possible.