20237-92-7Relevant articles and documents
Bioinspired Catalytic Reduction of Aqueous Perchlorate by One Single-Metal Site with High Stability against Oxidative Deactivation
Liu, Jinyong,Ren, Changxu
, p. 6715 - 6725 (2021)
Reduction of perchlorate (ClO4-) with an active and stable catalyst is of great importance for environmental, energy, and space technologies. However, after the rate-limiting oxygen atom transfer (OAT) from inert ClO4-, the much more reactive ClOx- (x ≤ 3) intermediates can cause catalyst deactivation. The previous Re-Pd/C catalyst contained a [ReV(O)(hoz)2]+ site (Hhoz = 2-(2′-hydroxyphenyl)-2-oxazoline) and readily reduced ClO4-, but ClOx- intermediates led to rapid formation and hydrolysis of [ReVII(O)2(hoz)2]+. While microbes use delicate enzymatic machinery to survive the oxidative stress during ClO4- reduction, a synthetic catalyst needs a straightforward self-protective design. In this work, we introduced a methyl group on the ligand oxazoline moiety and achieved a substantial enhancement of catalyst stability without sacrificing the performance of ClO4- reduction. A suite of kinetics measurement, X-ray photoelectron spectroscopy characterization, reaction modeling, stopped-flow photospectrometry, and 1H NMR monitoring revealed the underlying mechanism. The most critical and unexpected effect of the methyl group is the deceleration (for 2 orders of magnitude) of OAT from ClO3- to [ReV(O)(Mehoz)2]+. However, the rate of OAT with ClO4- was not affected. The methyl group also slowed down the hydrolysis of [ReVII(O)2(Mehoz)2]+ and allowed the introduction of methoxy onto the phenolate moiety to further accelerate ClO4- reduction. With 1 atm H2 at 20 °C, the Re-Pd/C catalyst used [ReV(O)(MehozOMe)2]+ as the only reaction site to reduce multiple spikes of 10 mM ClO4- into Cl- without decomposition. This work showcases the significant effect of simple ligand modification in improving catalyst stability for high-performance ClO4- reduction.
OXAZOLINE COMPOUND, CROSSLINKER AND RESIN COMPOSITION
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Paragraph 0036; 0037; 0038, (2019/03/07)
PROBLEM TO BE SOLVED: To provide an oxazoline compound and trioxazoline compound optimal as crosslinkers for a wide range of uses, including a coating agent, ink, a film, a binder, and adhesive or the like. SOLUTION: The present invention provides an oxazoline compound represented by the following chemical formula, a trioxazoline compound obtained by trifunctionalizing the oxazoline compound represented by the following chemical formula, and a crosslinker and a resin composition using the oxazoline compound or the trioxazoline compound. In the formula, X is H or R-OH, R is a C1-4 linear or branched alkylene group. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPO&INPIT
Configuration Control in the Synthesis of Homo- and Heteroleptic Bis(oxazolinylphenolato/thiazolinylphenolato) Chelate Ligand Complexes of Oxorhenium(V): Isomer Effect on Ancillary Ligand Exchange Dynamics and Implications for Perchlorate Reduction Catalysis
Liu, Jinyong,Wu, Dimao,Su, Xiaoge,Han, Mengwei,Kimura, Susana Y.,Gray, Danielle L.,Shapley, John R.,Abu-Omar, Mahdi M.,Werth, Charles J.,Strathmann, Timothy J.
, p. 2597 - 2611 (2016/03/19)
This study develops synthetic strategies for N,N-trans and N,N-cis Re(O)(LO-N)2Cl complexes and investigates the effects of the coordination spheres and ligand structures on ancillary ligand exchange dynamics and catalytic perchlorate reduction activities of the corresponding [Re(O)(LO-N)2]+ cations. The 2-(2′-hydroxyphenyl)-2-oxazoline (Hhoz) and 2-(2′-hydroxyphenyl)-2-thiazoline (Hhtz) ligands are used to prepare homoleptic N,N-trans and N,N-cis isomers of both Re(O)(hoz)2Cl and Re(O)(htz)2Cl and one heteroleptic N,N-trans Re(O)(hoz)(htz)Cl. Selection of hoz/htz ligands determines the preferred isomeric coordination sphere, and the use of substituted pyridine bases with varying degrees of steric hindrance during complex synthesis controls the rate of isomer interconversion. The five corresponding [Re(O)(LO-N)2]+ cations exhibit a wide range of solvent exchange rates (1.4 to 24,000 s-1 at 25°C) and different LO-N movement patterns, as influenced by the coordination sphere of Re (trans/cis), the noncoordinating heteroatom on LO-N ligands (O/S), and the combination of the two LO-N ligands (homoleptic/heteroleptic). Ligand exchange dynamics also correlate with the activity of catalytic reduction of aqueous ClO4- by H2 when the Re(O)(LO-N)2Cl complexes are immobilized onto Pd/C. Findings from this study provide novel synthetic strategies and mechanistic insights for innovations in catalytic, environmental, and biomedical research.
