REACTION KINETICS AND CHARACTERIZATION

<p><i>Operando</i> spectroelectrochemical analysis is used to determine the water oxidation reaction kinetics for hematite photoanodes prepared using four different synthetic procedures. Whilst these photoanodes exhibit very different current / voltage performance, their underlying water oxidation kinetics are found to be almost invariant. Lower photoanode performance was found to correlate with the observation of optical signals indicative of charge accumulation in mid-gap oxygen vacancy states, indicating these states do not contribute directly to water oxidation.</p>

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Kinetic Solvent Effects in Organic Reactions

10.26434/chemrxiv.5370778.v1 ◽

2017 ◽

Author(s):

Belinda Slakman ◽

Richard West

Keyword(s):

Solvent Effect ◽

Reaction Kinetics ◽

Computational Methods ◽

High Throughput ◽

Kinetic Modeling ◽

Solvent Effects ◽

Reaction Rates ◽

Prior Work ◽

Solvent Phase ◽

High Throughput Manner

<div> <div> <div> <p>This article reviews prior work studying reaction kinetics in solution, with the goal of using this information to improve detailed kinetic modeling in the solvent phase. Both experimental and computational methods for calculating reaction rates in liquids are reviewed. Previous studies, which used such methods to determine solvent effects, are then analyzed based on reaction family. Many of these studies correlate kinetic solvent effect with one or more solvent parameters or properties of reacting species, but it is not always possible, and investigations are usually done on too few reactions and solvents to truly generalize. From these studies, we present suggestions on how best to use data to generalize solvent effects for many different reaction types in a high throughput manner. </p> </div> </div> </div>

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An All-Photonic Molecular Amplifier and Binary Flip-flop

10.26434/chemrxiv.13277855 ◽

2020 ◽

Author(s):

Thomas MacDonald ◽

Timothy Schmidt ◽

Jonathon Beves

Keyword(s):

Numerical Modeling ◽

Visible Light ◽

Reaction Kinetics ◽

Memory Storage ◽

Chemical System ◽

Initial Composition ◽

Flip Flop ◽

Sequential Logic ◽

Behavior Based

A chemical system is proposed that is capable of amplifying small optical inputs into large changes in internal composition, based on a feedback interaction between switchable fluorescence and visible-light photoswitching. This system would demonstrate bifurcating reaction kinetics under irradiation and reach one of two stable photostationary states depending on the initial composition of the system. This behavior would allow the system to act as a chemical realization of the flip-flop circuit, the fundamental element in sequential logic and binary memory storage. We use detailed numerical modeling to demonstrate the feasibility of the proposed behavior based on known molecular phenomena, and comment on some of the conditions required to realize this system.

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Highly Electron-Deficient Pyridinium-Nitrones for Rapid and Tunable Inverse-Electron-Demand Strain-Promoted Alkyne-Nitrone Cycloaddition to Bicyclo[6.1.0]nonyne

10.26434/chemrxiv.8251370 ◽

2019 ◽

Author(s):

Praveen Gunawardene ◽

Wilson Luo ◽

Alexander M. Polgar ◽

John F. Corrigan ◽

Mark Workentin

Keyword(s):

Density Functional Theory ◽

Reaction Kinetics ◽

Density Functional ◽

Functional Theory ◽

X Ray ◽

Inverse Electron Demand ◽

X Ray Crystallography ◽

Electron Demand

<div> <div> <p>Highly accelerated inverse-electron-demand strain-promoted alkyne-nitrone cycloaddition (IED SPANC) between a sta- ble cyclooctyne (bicyclo[6.1.0]nonyne (BCN)) and nitrones delocalized into a Cα-pyridinium functionality is reported, with the most electron-deficient “pyridinium-nitrone” displaying among the most rapid cycloadditions to BCN that is currently reported. Density functional theory (DFT) and X-ray crystallography are explored to rationalize the effects of N- and Cα-substituent modifications at the nitrone on IED SPANC reaction kinetics and the overall rapid reactivity of pyridinium-delocalized nitrones.</p> </div> </div>

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