scholarly journals Copper(ii)-benzotriazole coordination compounds in click chemistry: a diagnostic reactivity study

2018 ◽  
Vol 47 (31) ◽  
pp. 10491-10508 ◽  
Author(s):  
Edward Loukopoulos ◽  
Alaa Abdul-Sada ◽  
Gizella Csire ◽  
Csilla Kállay ◽  
Adam Brookfield ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Click Chemistry ◽  
Coordination Compounds ◽  
Diagnostic Study ◽  
Reactivity Study ◽  
Shed Light

This diagnostic study aims to shed light on the catalytic activity of a library of Cu(ii) based coordination compounds with benzotriazole-based ligands.

Coordination compounds of titanium (IV) and 2-hydroxymethyl-phenol derivatives: Their synthesis, structure and catalytic activity in ethylene and 1-hexene polymerization

2015 ◽  
Vol 797 ◽  
pp. 159-164 ◽  
Author(s):  
Vladislav A. Tuskaev ◽  
Svetlana Ch Gagieva ◽  
Michail V. Solov'ev ◽  
Dmitrii A. Kurmaev ◽  
Nikolay A. Kolosov ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Coordination Compounds ◽  
Phenol Derivatives

scholarly journals Electronic effects in mixed N-heterocyclic carbene/phosphite indenylidene ruthenium metathesis catalysts

2019 ◽  
Vol 48 (30) ◽  
pp. 11326-11337 ◽  
Author(s):  
Yannick D. Bidal ◽  
César A. Urbina-Blanco ◽  
Albert Poater ◽  
David B. Cordes ◽  
Alexandra M. Z. Slawin ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Electronic Properties ◽  
Computational Studies ◽  
Electronic Effects ◽  
Metathesis Catalysts ◽  
Shed Light

Experimental and computational studies shed light on the role played by sacrificial ligand electronic properties on catalytic activity.

Syntheses and structures of two gold(i) coordination compounds derived from P–S hybrid ligands and their efficient catalytic performance in the photodegradation of nitroaromatics in water

2015 ◽  
Vol 44 (12) ◽  
pp. 5662-5671 ◽  
Author(s):  
Hai-Xiao Qi ◽  
Jian-Feng Wang ◽  
Zhi-Gang Ren ◽  
Jin-Jiao Ning ◽  
Jian-Ping Lang
Keyword(s):  
Catalytic Activity ◽  
Coordination Compounds ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Hybrid Ligands

Two Au–P–S complexes [Au2(dppatc)2]Cl2 and [Au(dppmt)]2 were prepared and they showed high catalytic activity toward the photodegradation of nitroaromatics in water.

Coordination compounds of chromium (+3) and vanadium (+3) and (+5) with 2,6-bis(diphenylhydroxymethyl)pyridyl ligand: Synthesis and study of catalytic activity in the polymerization of ethylene

2013 ◽  
Vol 396 ◽  
pp. 136-143 ◽  
Author(s):  
Dmitry A. Kurmaev ◽  
Nicolai A. Kolosov ◽  
Svetlana Ch. Gagieva ◽  
Alexandra O. Borissova ◽  
Vladislav A. Tuskaev ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Coordination Compounds ◽  
Ligand Synthesis ◽  
Pyridyl Ligand

scholarly journals Synergistic effects of functionally distinct substitutions in β-lactamase variants shed light on the evolution of bacterial drug resistance

2018 ◽  
Vol 293 (46) ◽  
pp. 17971-17984 ◽  
Author(s):  
Meha P. Patel ◽  
Liya Hu ◽  
Cameron A. Brown ◽  
Zhizeng Sun ◽  
Carolyn J. Adamski ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Conformational Changes ◽  
Active Site ◽  
Enzyme Stability ◽  
Synergistic Effects ◽  
Catalytic Efficiency ◽  
Bacterial Drug Resistance ◽  
Natural Variant ◽  
Loop Conformation ◽  
Shed Light

The CTX-M β-lactamases have emerged as the most widespread extended-spectrum β-lactamases (ESBLs) in Gram-negative bacteria. These enzymes rapidly hydrolyze cefotaxime, but not the related cephalosporin, ceftazidime. ESBL variants have evolved, however, that provide enhanced ceftazidime resistance. We show here that a natural variant at a nonactive site, i.e. second-shell residue N106S, enhances enzyme stability but reduces catalytic efficiency for cefotaxime and ceftazidime and decreases resistance levels. However, when the N106S variant was combined with an active-site variant, D240G, that enhances enzyme catalytic efficiency, but decreases stability, the resultant double mutant exhibited higher resistance levels than predicted on the basis of the phenotypes of each variant. We found that this epistasis is due to compensatory effects, whereby increased stability provided by N106S overrides its cost of decreased catalytic activity. X-ray structures of the variant enzymes in complex with cefotaxime revealed conformational changes in the active-site loop spanning residues 103–106 that were caused by the N106S substitution and relieve steric strain to stabilize the enzyme, but also alter contacts with cefotaxime and thereby reduce catalytic activity. We noted that the 103–106 loop conformation in the N106S-containing variants is different from that of WT CTX-M but nearly identical to that of the non-ESBL, TEM-1 β-lactamase, having a serine at the 106 position. Therefore, residue 106 may serve as a “switch” that toggles the conformations of the 103–106 loop. When it is serine, the loop is in the non-ESBL, TEM-like conformation, and when it is asparagine, the loop is in a CTX-M–like, cefotaximase-favorable conformation.

Catalytic Activity of Copper Oxide/Zinc Oxide Composites Prepared by Thermolysis of Crystallographically Defined Bimetallic Coordination Compounds.

ChemInform ◽  
2006 ◽  
Vol 37 (31) ◽  
Author(s):  
Rainer Weiss ◽  
Yanzhi Guo ◽  
Sascha Vukojevic ◽  
Lamma Khodeir ◽  
Roland Boese ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Catalytic Activity ◽  
Copper Oxide ◽  
Coordination Compounds ◽  
Oxide Composites

scholarly journals SIRT1 Modulators in Experimentally Induced Liver Injury

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Hassan Farghali ◽  
Mighty Kgalalelo Kemelo ◽  
Nikolina Kutinová Canová
Keyword(s):  
Catalytic Activity ◽  
Antioxidant Enzymes ◽  
Liver Injury ◽  
Inverse Relationship ◽  
Major Step ◽  
Sirt1 Expression ◽  
Hepatoprotective Effects ◽  
Fine Tune ◽  
Shed Light ◽  
Pharmacologic Modulation

This article is directed at highlighting the involvement of the endogenous stress sensor SIRT1 (silent information regulator T1) as a possible factor involved in hepatoprotection. The selective SIRT1 modulators whether activators (STACs) or inhibitors are being tried experimentally and clinically. We discuss the modulation of SIRT1 on cytoprotection or even cytotoxicity in the liver chemically injured by hepatotoxic agents in rats, to shed light on the crosstalk between SIRT1 and its modulators. A combination of D-galactosamine and lipopolysaccharide (D-GalN/LPS) downregulated SIRT1 expression, while SIRT1 activators, SRT1720, resveratrol, and quercetin, upregulated SIRT1 and alleviated D-GalN/LPS-induced acute hepatotoxicity. Liver injury markers exhibited an inverse relationship with SIRT1 expression. However, under subchronic hepatotoxicity, quercetin decreased the significant increase in SIRT1 expression to lower levels which are still higher than normal ones and mitigated the liver-damaging effects of carbon tetrachloride. Each of these STACs was hepatoprotective and returned the conventional antioxidant enzymes to the baseline. Polyphenols tend to fine-tune SIRT1 expression towards normal in the liver of intoxicated rats in both acute and subchronic studies. Together, all these events give an impression that the cytoprotective effects of SIRT1 are exhibited within a definite range of expression. The catalytic activity of SIRT1 is important in the hepatoprotective effects of polyphenols where SIRT1 inhibitors block and the allosteric SIRT1 activators mimic the hepatoprotective effects of polyphenols. Our findings indicate that the pharmacologic modulation of SIRT1 could represent both an important move in alleviating hepatic insults and a future major step in the treatment of xenobiotic-induced hepatotoxicity.

scholarly journals Semiconductor-free nanoplasmonic photoelectrochemistry of H2O2 over Ag nanowires

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Ying-Chu Chen ◽  
Ying-Zhen Chen ◽  
Yu-Kuei Hsu
Keyword(s):  
Catalytic Activity ◽  
Phase Boundary ◽  
Reaction Rate ◽  
Underlying Mechanism ◽  
Great Promise ◽  
Carbon Cloth ◽  
Proof Of Concept ◽  
Ag Nanowires ◽  
Conductive Properties ◽  
Shed Light

AbstractNanoplasmonics is currently experiencing an ongoing renaissance as a result of the booming research interest in LSPR-mediated but semiconductor-free photocatalysis and photoelectrochemistry directly over nanometals with excellent catalytic activity and conductive properties. To shed light on the underlying mechanism, the present study puts forward H2O2 as the probe molecule, with which the electroreduction at the phase boundary with photoexcited Ag nanowires (NWs) was systemically investigated. In particular, the reaction rate depends not only linearly on the illumination intensity but also on the resonant wavelength of the characteristic LSPR of the Ag NWs, evidently illustrating that the photoelectrochemical H2O2 reduction is mediated by the LSPR-induced energetic electrons of the Ag NWs. In addition to the mechanistic insights, the present study further highlights the great promise of such semiconductor-free LSPR-mediated photoelectrochemistry of H2O2 over Ag NWs in the analytical biochemistry field via proof-of-concept solar photoelectrochemical detection of ultradiluted H2O2 in PBS. The Ag NWs deposited on a carbon cloth substrate as the working electrode exhibit excellent sensitivity amounting to 118 μA cm−2 mM−1 under solar illumination, well outperforming that of the electrochemical counterpart measured in the dark by 50%.

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