Tetraphenylethylene AIEgen bearing thiophenylbipyridine receptor for selective detection of copper(II) ion

2021 ◽  
Author(s):  
Dinesh N Nadimetla ◽  
Sheshanath Bhosale
Keyword(s):  
Reaction Pathway ◽  
Selective Detection ◽  
Multistep Reaction

Highly emissive tetraphenylethylene (TPE) chromophore appended thiophenylbipyridine pendant as a receptor (1) site has been successively synthesized via multistep reaction pathway. The synthesized chromophore 1 was been well characterized by...

Dehalogenation of 5-bromouracil by bisulfite buffers. Kinetic evidence for a multistep reaction pathway

1975 ◽  
Vol 97 (19) ◽  
pp. 5572-5577 ◽  
Author(s):  
Frank A. Sedor ◽  
Dan G. Jacobson ◽  
Eugene G. Sander
Keyword(s):  
Reaction Pathway ◽  
Multistep Reaction

scholarly journals Mechanistic Insights into Water-Catalyzed Formation of Levoglucosenone from Anhydrosugar Intermediates by Means of High-Level Theoretical Procedures

2016 ◽  
Vol 69 (9) ◽  
pp. 943 ◽  
Author(s):  
Wenchao Wan ◽  
Li-Juan Yu ◽  
Amir Karton
Keyword(s):  
Activation Energy ◽  
Reaction Mechanism ◽  
Ring Opening ◽  
Reaction Pathway ◽  
Fast Pyrolysis ◽  
Rate Determining Step ◽  
Dehydration Reactions ◽  
High Level ◽  
Multistep Reaction ◽  
Hydration And Dehydration

Levoglucosenone (LGO) is an important anhydrosugar product of fast pyrolysis of cellulose and biomass. We use the high-level G4(MP2) thermochemical protocol to study the reaction mechanism for the formation of LGO from the 1,4:3,6-dianhydro-α-d-glucopyranose (DGP) pyrolysis intermediate. We find that the DGP-to-LGO conversion proceeds via a multistep reaction mechanism, which involves ring-opening, ring-closing, enol-to-keto tautomerization, hydration, and dehydration reactions. The rate-determining step for the uncatalyzed process is the enol-to-keto tautomerization (ΔG‡298 = 68.6 kcal mol–1). We find that a water molecule can catalyze five of the seven steps in the reaction pathway. In the water-catalyzed process, the barrier for the enol-to-keto tautomerization is reduced by as much as 15.1 kcal mol–1, and the hydration step becomes the rate-determining step with an activation energy of ΔG‡298 = 58.1 kcal mol–1.

scholarly journals Template-Directed Catalysis of a Multistep Reaction Pathway for Nonenzymatic RNA Primer Extension

Biochemistry ◽  
2018 ◽  
Vol 58 (6) ◽  
pp. 755-762 ◽  
Author(s):  
Travis Walton ◽  
Lydia Pazienza ◽  
Jack W. Szostak
Keyword(s):  
Reaction Pathway ◽  
Primer Extension ◽  
Multistep Reaction

scholarly journals Multistep Reaction Pathway for CO 2 Reduction on Hydride‐Capped Si Nanosheets

ChemCatChem ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 722-725 ◽  
Author(s):  
Lixue Xia ◽  
Xiaobin Liao ◽  
Qiu He ◽  
Huan Wang ◽  
Yan Zhao ◽  
...  
Keyword(s):  
Reaction Pathway ◽  
Multistep Reaction

Selective detection of glutathione based on the recovered fluorescence of BSA‐AuNCs/Cu 2+ system

2019 ◽  
Vol 14 (9) ◽  
pp. 952-956
Author(s):  
Yining Zhu ◽  
Wang Li ◽  
Cheng Ju ◽  
Xiang Gong ◽  
Wenhao Song ◽  
...  
Keyword(s):  
Selective Detection

Catalytic Resonance Theory: Parallel Reaction Pathway Control

2019 ◽  
Author(s):  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anatoliy Kuznetsov ◽  
Qi Zhang ◽  
Phillip Christopher ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Active Site ◽  
Active Sites ◽  
Reaction Pathway ◽  
Control Strategies ◽  
Oscillation Amplitude ◽  
Catalytic Performance ◽  
Parallel Reaction ◽  
Resonance Theory ◽  
Static Conditions

Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites, but dramatically greater rate acceleration on that same active site is achieved when the surface intermediates oscillate in binding energy. The applied oscillation amplitude and frequency can accelerate reactions orders of magnitude above the catalytic rates of static systems, provided the active site dynamics are tuned to the natural frequencies of the surface chemistry. In this work, differences in the characteristics of parallel reactions are exploited via selective application of active site dynamics (0 < ΔU < 1.0 eV amplitude, 10<sup>-6</sup> < f < 10<sup>4</sup> Hz frequency) to control the extent of competing reactions occurring on the shared catalytic surface. Simulation of multiple parallel reaction systems with broad range of variation in chemical parameters revealed that parallel chemistries are highly tunable in selectivity between either pure product, even when specific products are not selectively produced under static conditions. Two mechanisms leading to dynamic selectivity control were identified: (i) surface thermodynamic control of one product species under strong binding conditions, or (ii) catalytic resonance of the kinetics of one reaction over the other. These dynamic parallel pathway control strategies applied to a host of chemical conditions indicate significant potential for improving the catalytic performance of many important industrial chemical reactions beyond their existing static performance.

Development of Ultrasensitive and Arsenic (III) Selective Upconverting (NaYF4: Yb3+, Er3+) Platform

2020 ◽  
Author(s):  
Suman Duhan ◽  
Kedar Sahoo ◽  
Sudhir Kumar Singh ◽  
Manoj Kumar
Keyword(s):  
Heavy Ions ◽  
Leaf Extract ◽  
Moringa Oleifera ◽  
Solid Phase ◽  
Selective Detection ◽  
Arsenic Pollution ◽  
Apparent Effect ◽  
Safe Limit ◽  
Interfering Ions ◽  
Resonance Transfer

The development of a sensitive alpha-NaYF4:Yb3+, Er3+ solid-phase upconverting platform (UCP) has been realized using Moringa oleifera leaf extract for selective detection of arsenic (As III) contamination in drinking water. The presence of polyphenols in the leaves extract is shown to induce luminescence resonance transfer (LRET), diminishing thereby the Er3+ upconverting red and green emissions activated by 980 nm excitation. However, addition of As3+ species interrupts the LRET process and restores emission proportionately. This feature allows platform to selectively detect arsenic pollution in water below the safe limit of 10 ppt. The uniqueness of UCP lies in monitoring the As3+ contamination in samples containing heavy ions (Cd2+, Hg2+) as well, without apparent effect on the signal reproducibility. UCP is also found to be insensitive to other interfering ions like Pb2+, H2PO4-, F-, Cl-, Ca2+, Mg2+, Sn2+, Cr6+, Fe2+ and Co2+, if present.<br><br>

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