A multi target approach to control chemical reactions in their inhomogeneous solvent environment

2015 ◽  
Vol 48 (23) ◽  
pp. 234003 ◽  
Author(s):  
Daniel Keefer ◽  
Sebastian Thallmair ◽  
Julius P P Zauleck ◽  
Regina de Vivie-Riedle
Keyword(s):  
Chemical Reactions ◽  
Control Chemical ◽  
Solvent Environment

scholarly journals A chemical reaction controlled by light-activated molecular switches based on hetero-cyclopentanediyls

2019 ◽  
Vol 10 (12) ◽  
pp. 3486-3493 ◽  
Author(s):  
Jonas Bresien ◽  
Thomas Kröger-Badge ◽  
Stefan Lochbrunner ◽  
Dirk Michalik ◽  
Henrik Müller ◽  
...  
Keyword(s):  
Small Molecules ◽  
Computational Methods ◽  
Chemical Reactions ◽  
Chemical Reaction ◽  
Molecular Switches ◽  
Control Chemical

Biradicals were applied as molecular switches to control chemical reactions that involve the activation of small molecules. The mechanism was studied by experimental and computational methods.

scholarly journals Modulation of Prins Cyclization by Vibrational Strong Coupling

2019 ◽  
Author(s):  
Kenji Hirai ◽  
Rie Takeda ◽  
JAMES HUTCHISON ◽  
Hiroshi Uji-i
Keyword(s):  
Strong Coupling ◽  
Chemical Reactions ◽  
Reaction Pathway ◽  
Chemical Reactivity ◽  
Order Rate Constant ◽  
Pharmaceutical Chemistry ◽  
Prins Cyclization ◽  
Control Chemical ◽  
Aldehydes And Ketones ◽  
Enthalpy And Entropy

<div>Light-molecule strong coupling has emerged within the last decade as an entirely new method to control chemical reactions. A few years ago it was discovered that the chemical reactivity could be altered by vibrational strong coupling (VSC). While the potential of VSC in organic chemistry appears enormous, only a limited number of reactions have been investigated under VSC to date, including solvolysis and deprotection reactions. Here we investigate the effect of VSC on a series of aldehydes and ketones undergoing Prins cyclization, an important synthetic step in pharmaceutical chemistry. We observe a decrease of the second-order rate constant with VSC of the reactant carbonyl stretching groups. We measure an increased activation energy due to VSC, but proportional changes in activation enthalpy and entropy suggest no substantive change in reaction pathway. The addition of common cycloaddition reactions to the stable of VSC-modified chemical reactions is another step towards establishing VSC as a genuine tool for synthetic chemistry.</div>

A Study To Control Chemical Reactions Using Si:2p Core Ionization: Site-Specific Fragmentation

2011 ◽  
Vol 115 (32) ◽  
pp. 8822-8831 ◽  
Author(s):  
Shin-ichi Nagaoka ◽  
Hironobu Fukuzawa ◽  
Georg Prümper ◽  
Mai Takemoto ◽  
Osamu Takahashi ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Site Specific ◽  
Control Chemical

scholarly journals A tutored discourse on microcontrollers, single board computers and their applications to monitor and control chemical reactions

2020 ◽  
Vol 5 (2) ◽  
pp. 201-220 ◽  
Author(s):  
Daniel E. Fitzpatrick ◽  
Matthew O'Brien ◽  
Steven V. Ley
Keyword(s):  
Low Power ◽  
Chemical Reactions ◽  
Control Chemical ◽  
And Control ◽  
Monitor And Control

This Tutored Discourse constitutes a preliminary exposure on how synthesis chemists can engage positively with inexpensive, low-power microcontrollers to aid control, monitoring and optimisation of chemical reactions.

scholarly journals Comparison of alkene hydrogenation in carbon nanoreactors of different diameters: probing the effects of nanoscale confinement on ruthenium nanoparticle catalysis

2017 ◽  
Vol 5 (40) ◽  
pp. 21467-21477 ◽  
Author(s):  
Mehtap Aygün ◽  
Craig T. Stoppiello ◽  
Maria A. Lebedeva ◽  
Emily F. Smith ◽  
Maria del Carmen Gimenez-Lopez ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Optimum Level ◽  
Control Chemical ◽  
Competitive Hydrogenation ◽  
Hydrogenation Reactions ◽  
Alkene Hydrogenation ◽  
Nanoparticle Catalysis ◽  
Different Diameters

Exploratory, competitive hydrogenation reactions reveal the optimum level of confinement to control chemical reactions.

scholarly journals Modulation of Prins Cyclization by Vibrational Strong Coupling

2019 ◽  
Author(s):  
Kenji Hirai ◽  
Rie Takeda ◽  
JAMES HUTCHISON ◽  
Hiroshi Uji-i
Keyword(s):  
Strong Coupling ◽  
Chemical Reactions ◽  
Reaction Pathway ◽  
Chemical Reactivity ◽  
Order Rate Constant ◽  
Pharmaceutical Chemistry ◽  
Prins Cyclization ◽  
Control Chemical ◽  
Aldehydes And Ketones ◽  
Enthalpy And Entropy

<div>Light-molecule strong coupling has emerged within the last decade as an entirely new method to control chemical reactions. A few years ago it was discovered that the chemical reactivity could be altered by vibrational strong coupling (VSC). While the potential of VSC in organic chemistry appears enormous, only a limited number of reactions have been investigated under VSC to date, including solvolysis and deprotection reactions. Here we investigate the effect of VSC on a series of aldehydes and ketones undergoing Prins cyclization, an important synthetic step in pharmaceutical chemistry. We observe a decrease of the second-order rate constant with VSC of the reactant carbonyl stretching groups. We measure an increased activation energy due to VSC, but proportional changes in activation enthalpy and entropy suggest no substantive change in reaction pathway. The addition of common cycloaddition reactions to the stable of VSC-modified chemical reactions is another step towards establishing VSC as a genuine tool for synthetic chemistry.</div>

Surface reactions observed by photoemission electron microscopy (PEEM)

1992 ◽  
Vol 50 (1) ◽  
pp. 286-287
Author(s):  
H.H. Rotermund
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Work Function ◽  
Chemical Reactions ◽  
Reaction Diffusion ◽  
Dynamic Processes ◽  
Clean Surface ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Photoemission Electron

Chemical reactions at a surface will in most cases show a measurable influence on the work function of the clean surface. This change of the work function δφ can be used to image the local distributions of the investigated reaction,.if one of the reacting partners is adsorbed at the surface in form of islands of sufficient size (Δ>0.2μm). These can than be visualized via a photoemission electron microscope (PEEM). Changes of φ as low as 2 meV give already a change in the total intensity of a PEEM picture. To achieve reasonable contrast for an image several 10 meV of δφ are needed. Dynamic processes as surface diffusion of CO or O on single crystal surfaces as well as reaction / diffusion fronts have been observed in real time and space.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

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