Exploring 1,2-Hydrogen Shift in Silicon Nanoparticles: Reaction Kinetics from Quantum Chemical Calculations and Derivation of Transition State Group Additivity Database

2009 ◽  
Vol 113 (41) ◽  
pp. 10933-10946 ◽  
Author(s):  
Andrew J. Adamczyk ◽  
Marie-Francoise Reyniers ◽  
Guy B. Marin ◽  
Linda J. Broadbelt
Keyword(s):  
Transition State ◽  
Reaction Kinetics ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Silicon Nanoparticles ◽  
Group Additivity ◽  
Hydrogen Shift ◽  
State Group

Acylation-Mediated ‘Kinetic Turn-On’ of 3-Amino-1,2,4,5-tetrazines

Synlett ◽  
2018 ◽  
Vol 29 (10) ◽  
pp. 1297-1302 ◽  
Author(s):  
Hannes Mikula ◽  
Stefan Kronister ◽  
Dennis Svatunek ◽  
Christoph Denk
Keyword(s):  
Reaction Kinetics ◽  
Electronic Properties ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Biomedical Sciences ◽  
Target Molecule ◽  
Remarkable Increase ◽  
Turn On ◽  
The Impact ◽  
Strained Alkenes

The fast and biocompatible ligation of 1,2,4,5-tetrazines with strained alkenes has found numerous applications in biomedical sciences. The reactivity of a 1,2,4,5-tetrazine can generally be tuned by changing its electronic properties by varying the substituents in the 3- and/or 6-position. An increased reactivity of such bioorthogonal probes upon conjugation or attachment to a target molecule has not previously been described. Such an approach would be beneficial, as it would minimize the impact of residual tetrazine reagents and/or impurities. Herein, we describe such a ‘kinetic turn-on’ of 1,2,4,5-tetrazines upon conjugation. On the basis of the significant increase in reactivity following N-acylation predicted by quantum chemical calculations, we prepared 3-aminotetrazines and their corresponding acetylated derivatives. An investigation of the reaction kinetics indeed revealed a remarkable increase in reactivity upon acylation.

scholarly journals Arsenate and Arsenite Reaction Kinetics with Ferric Hydroxides Using Quantum Chemical Calculations

2018 ◽  
Vol 5 (3) ◽  
pp. 144-149
Author(s):  
Cijin J. George ◽  
◽  
Sougata Santra ◽  
G. V. Zyryanov ◽  
Kousik Giri ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical

scholarly journals Computational Study of Electronic Influence of Guanidine Substitution on Diels-Alder Reactions of Heterocyclic Dienes

2019 ◽  
Vol 92 (2) ◽  
pp. 279-286
Author(s):  
Ivana Antol ◽  
Luka Barešić ◽  
Zoran Glasovac ◽  
Davor Margetić
Keyword(s):  
Transition State ◽  
Quantum Chemical Calculations ◽  
Electronic Structures ◽  
Quantum Chemical ◽  
Computational Study ◽  
Cycloaddition Reaction ◽  
Diels Alder ◽  
Reaction Barriers ◽  
Reactivity Order

Quantum-chemical calculations of cycloaddition properties of cyclic heterodienes substituted with guanidine functionality were carried out. Molecular and electronic structures of series of dienes (pyrrole, furan, thiophene, isoindole and 1,3-butadiene) were calculated and reactivity order established on the basis of FMO theory. Transition state calculations of model [4+2] cycloaddition reaction with acetylene indicate that guanidine substitution influences reaction barriers in moderate extent (up to ~4 kcal mol–1). The substitution position plays an important role on the sign and magnitude of the effect and protonation of nitrogen possessing substituents increases reactivity of dienes.

scholarly journals Comparison of Model Systems (M+)n·[CrX63−] and M3CrX6+ 18MX Based on Quantum-Chemical Calculations (X: F, Cl)

2016 ◽  
Vol 2016 ◽  
pp. 1-5
Author(s):  
Vyacheslav Kremenetsky ◽  
Sergey Kuznetsov
Keyword(s):  
Electron Transfer ◽  
Transition State ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Computer Time ◽  
Model Systems ◽  
Preliminary Deformation ◽  
Initial State ◽  
Before And After ◽  
Lowest Unoccupied Molecular Orbitals

On the basis of quantum-chemical calculations the most stable particle compositions are estimated in such model systems as (M+)n·[CrCl6] and M3CrCl6+ 18MCl (M = Na, K, and Cs). In all systems these particles are positively charged. For systems (M+)n·[CrCl6], (M+)n·[CrF6], M3CrF6+ 18MCl, M3CrF6+ 18MF, and M3CrCl6+ 18MCl (M = Na, K, and Cs) a number of energy parameters characterizing the state of the system before and after electron transfer are calculated. The results indicate the possibility of electron transfer from the cathode to the melt system, which is in the initial state. However, this possibility cannot be realized in systems where LUMOs (lowest unoccupied molecular orbitals) have purely ligand character. In this case, the preliminary deformation of a cationic shell of electroactive species is required; it transforms the initial system to the transition state. However, in all considered systems the search of the transition state should be carried close to the initial statePi. This greatly simplifies a problem and transforms it from a purely theoretical sphere to the field of practical tasks that do not require exceptional cost of computer time.

Sign in / Sign up

Export Citation Format

Share Document