scholarly journals Substituent and structural effects on the kinetics of the reaction of N-(substituted phenylmethylene)-m- and -p-aminobenzoic acids with diazodiphenylmethane

2007 ◽  
Vol 72 (12) ◽  
pp. 1191-1200 ◽  
Author(s):  
Bratislav Jovanovic ◽  
Aleksandar Marinkovic ◽  
Zeljko Vitnik ◽  
Ivan Juranic
Keyword(s):  
Molecular Structure ◽  
Rate Constants ◽  
Experimental Results ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Structural Effects ◽  
Electronic Effects ◽  
Aminobenzoic Acids ◽  
Kinetics Of ◽  
Insight Into

The rate constants for the reaction of twenty-two N-(substituted phenylmethylene)- m- and -p-aminobenzoic acids with diazodiphenylmethane were determined in absolute ethanol at 30 ?C. The effects of substituents on the reactivity of the investigated compounds were interpreted by correlation of the rate constants with LFER equations. The results of quantum mechanical calculations of the molecular structure together with experimental results gave a better insight into the effects of structure on the transmission of electronic effects of the substituents. New ? constants for substituted benzylideneamino group were calculated.

Insight into 6-aminopenicillanic acid structure and study of the quantum mechanical calculations of the acid–base site on γ-Fe2O3@SiO2 core–shell nanocomposites and as efficient catalysts in multicomponent reactions

2020 ◽  
Vol 44 (47) ◽  
pp. 20688-20696
Author(s):  
Farveh Saberi ◽  
Somayeh Ostovar ◽  
Roya Behazin ◽  
Alireza Rezvani ◽  
Ali Ebrahimi ◽  
...  
Keyword(s):  
Multicomponent Reactions ◽  
Quantum Mechanical ◽  
Core Shell ◽  
Quantum Mechanical Calculations ◽  
Acid Base ◽  
Base Site ◽  
Insight Into ◽  
Acid Structure

Magnetic 6-APA/γ-Fe2O3@Sio2 nanocomposites have been developed by exploiting the potential of the acid–base bifunctional system to study the quantum mechanistic calculations.

Annealing experiments on CO2-bearing jadeite glass: an insight into the true temperature dependence of CO2 speciation in silicate melts

2001 ◽  
Vol 65 (6) ◽  
pp. 701-707 ◽  
Author(s):  
Y. Morizet ◽  
S. C. Kohn ◽  
R. A. Brooker
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Negative Charge ◽  
Silicate Melts ◽  
True Temperature ◽  
Carbonate Group ◽  
Image Position ◽  
Kinetics Of ◽  
Annealing Experiments ◽  
Insight Into

AbstractThe thermodynamics and kinetics of CO2 speciation in silicate melts have been studied by measuring the concentration of CO2mol and carbonate in jadeite glass annealed at 575, 450 and 400°C. Assuming that the reaction is1where CO2mol..Obr represents a CO2 molecule weakly bonded to a bridging oxygen in the network and CO3 represents a bridging carbonate group with no net negative charge, ΔH for the reaction is –17 (+4/–8) kJ mol−1 and ΔS is –24 (+6/–9) J K−1 mol−1. The rate of equilibration of the species was measured at each temperature and the rate constants were deduced. The temperature dependence of the rate constants was used to determine the activation energy of the forward and reverse reactions which are 68 (+3/–31) kJ mol−1 and 86 (+1/–69) kJ mol−1 respectively. The data suggest that CO2mol may be much more abundant in silicate melts than previously assumed on the basis of studies of CO2-bearing glasses. Models of solubility, diffusion, and isotope fractionation should take this into account.

PRESSURE-INDUCED STRUCTURAL EFFECTS IN SEMICONDUCTORS

1993 ◽  
Vol 07 (27) ◽  
pp. 4555-4593 ◽  
Author(s):  
J. CRAIN
Keyword(s):  
High Pressure ◽  
Computational Methods ◽  
Short Range ◽  
Short Range Order ◽  
Computational Physics ◽  
Range Order ◽  
Experimental Results ◽  
Structural Effects ◽  
Electronic Effects ◽  
Structural Polymorphism

Recent advances in the understanding of pressure-induced structural and electronic effects in semiconductors have been made possible through developments in both experimental and computational physics. It is shown that the A N B 8−N compounds which include the tetrahedrally coordinated III–V semiconductors exhibit a far richer degree of pressure-induced structural polymorphism than was originally believed. In addition, entirely new factors such as defects, short-range order and irreversibility have been identified as playing potentially important roles in the high pressure behavior of semiconductors. The experimental results are reviewed and discussed in the context of models which are amenable to investigation by modern theoretical and computational methods.

scholarly journals Report on the Real Structure of Benzene Molecules and the Thickness of Graphene

2021 ◽  
Author(s):  
Ning Wang ◽  
Dulun Wang
Keyword(s):  
Molecular Structure ◽  
Layer Structure ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Quantum Mechanical ◽  
Ultraviolet Spectroscopy ◽  
Quantum Mechanical Calculations ◽  
Covalent Bonds ◽  
Wide Range ◽  
Long Time

Abstract The problem of the benzene molecular structure has not been solved for a long time. This research proposes a new concept of covalent bonds based on the existing theory: each electron shared by the nucleus corresponds to a half-valent bond, and a half-valent bond can be formed between interval carbon atoms of the benzene ring. A new theory was established. Quantum mechanical calculations results can quantitatively explain experimental results, such as the hydrogenation heat and ultraviolet spectroscopy of benzene. It has solved more than one hundred years of difficult problems. The design of the new structural forms of benzene molecules shows half-valent bonds with dotted lines, which have a wide range of adaptability, and shows the structural forms and reaction formulas of more than dozens of benzene homologs and derivatives. Under the guidance of the new theory, the stacked three-dimensional structure of benzene was explored. The thickness of the three-layer benzene tube is calculated to be almost equal to the thickness of the graphene. Therefore, it is speculated that graphene may be a three layer structure.

Molecular structure of Hf(BH4)4 investigated by quantum mechanical calculations and gas-phase electron diffraction

2004 ◽  
pp. 967 ◽  
Author(s):  
Konstantin B. Borisenko ◽  
Anthony J. Downs ◽  
Heather E. Robertson ◽  
David W. H. Rankin ◽  
Christina Y. Tang
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Gas Phase ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Gas Phase Electron Diffraction

The H + HeH+ → He + H2+ reaction from the ultra-cold regime to the three-body breakup: exact quantum mechanical integral cross sections and rate constants

2014 ◽  
Vol 16 (23) ◽  
pp. 11662-11672 ◽  
Author(s):  
Dario De Fazio
Keyword(s):  
Cross Sections ◽  
Rate Constants ◽  
Quantum Mechanical ◽  
Theoretical Studies ◽  
Quantum Mechanical Calculations ◽  
Exact Quantum ◽  
Three Body ◽  
Experimental And Theoretical Studies

Benchmark quantum mechanical calculations from the Wigner's regime to the three-body breakup are compared to previous experimental and theoretical studies.

Sign in / Sign up

Export Citation Format

Share Document