An All-Photonic Molecular Amplifier and Binary Flip-flop

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

Corrigendum to: Time-Resolved Diffusion NMR Measurements for Transient Processes (ChemPhysChem, (2019), 20, 7, (926-930), 10.1002/cphc.201900150)

Since publication of this work it has been brought to the authors’ attention that the use of shuffled gradients and moving average processing has been previously reported in a seminal publication by Kazimierczuk and co-workers, where the approach was applied to diffusion measurements of polymer mixtures, including polymers undergoing active fragmentation. This publication should have been cited in our work and we apologize for this unfortunate oversight

Time-Resolved Diffusion NMR Measurements for Transient Processes

A general procedure for measurement of time-resolved diffusion coefficients of molecular species by NMR is described, including the use of methanol for fast temperature-independent gradient calibration

Enhanced Diffusion of Molecular Catalysts is Due to Convection

Intriguing reports of enhanced diffusion in enzymes and molecular catalysts have spurred significant interest in experimental and theoretical investigations, and the mechanism of this phenomenon is the topic of lively debate. Here we use time-resolved diffusion NMR methods to measure the diffusion coefficients (D) of small molecule species involved in chemical reactions with high temporal resolution. We show the enhanced diffusion of small molecules cannot be explained by reaction velocity, and that apparent measurements of enhanced diffusion by small molecules appear to be caused by bulk fluid flow processes such as convection