scholarly journals Solvent and Substituent Effects on the Phosphine + CO2 Reaction

Inorganics ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 110 ◽  
Author(s):  
Ibon Alkorta ◽  
Cristina Trujillo ◽  
Goar Sánchez-Sanz ◽  
José Elguero
Keyword(s):  
Transition State ◽  
Solvent Effects ◽  
Theoretical Study ◽  
Substituent Effects ◽  
Stationary Points ◽  
Pnicogen Bond ◽  
Solvent Models ◽  
Moller Plesset ◽  
The Stability ◽  
Computational Level

A theoretical study of the substituent and solvent effects on the reaction of phosphines with CO2 has been carried out by means of Møller-Plesset (MP2) computational level calculations and continuum polarizable method (PCM) solvent models. Three stationary points along the reaction coordinate have been characterized, a pre-transition state (TS) assembly in which a pnicogen bond or tetrel bond is established between the phosphine and the CO2 molecule, followed by a transition state, and leading finally to the adduct in which the P–C bond has been formed. The solvent effects on the stability and geometry of the stationary points are different. Thus, the pnicogen bonded complexes are destabilized as the dielectric constant of the solvent increases while the opposite happens within the adducts with the P–C bond and the TSs trend. A combination of the substituents and solvents can be used to control the most stable minimum.

scholarly journals A G2(MP2) theoretical study of substituent effects on H3BNHnCl3−n (n= 3-0) donor-acceptor complexes

2008 ◽  
Vol 6 (3) ◽  
pp. 400-403 ◽  
Author(s):  
Hafid Anane ◽  
Soufiane Houssame ◽  
Abdelali Guerraze ◽  
Abdeladim Guermoune ◽  
Abderrahim Boutalib ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Substituent Effects ◽  
Lone Pair ◽  
Proton Affinities ◽  
Lone Pair Orbital ◽  
Chlorine Substitution ◽  
Donor Acceptor ◽  
Nitrogen Lone Pair ◽  
The Stability ◽  
N Compounds

AbstractThe complexation energies of H3BNHnCl3−n (n= 3-0) complexes and the proton affinities of NHnCl3−n compounds have been computed at the G2(MP2) level of theory. G2(MP2) results show that the successive chlorine substitution on the ammonia decreases both the basicity of the NHnCl3−n ligands and the stability of H3BNHnCl3−n complexes. The findings are interpreted in terms of the rehybridisation of the nitrogen lone-pair orbital. The NBO partitioning scheme shows that the variation of the N-H and N-Cl bond lengths, upon complexation, is due to variation of “s” character in these bonds.

Kinetics of reactions of para-substituted phenyl isocyanates with amines and alcohols

1991 ◽  
Vol 56 (8) ◽  
pp. 1662-1670 ◽  
Author(s):  
Ivan Danihel ◽  
Falk Barnikol ◽  
Pavol Kristian
Keyword(s):  
Transition State ◽  
Solvent Effects ◽  
Rate Constants ◽  
Substituent Effects ◽  
Steric Effects ◽  
Stopped Flow ◽  
Partial Charges ◽  
Hammett Correlation ◽  
One Step ◽  
Kinetics Of

The reaction of para-substituted phenyl isocyanates with amines and alcohols was studied by stopped-flow method. The Hammett correlation obtained showed that the sensitivity of the above mentioned reactions toward substituent effects is the same as that of analogous reactions of phenyl isothiocyanates (ρ ~ 2). The rate constants of these reactions were found to be affected more by steric effects than by solvent effects. An one step multicentre mechanism with partial charges in transition state has been proposed for the title reactions.

Thermolysis of 5,5-dimethyl-4-aryl-Δ1-1,2,4-triazolin-3-ones in solution. Products, kinetics, substituent effects, and solvent effects

1981 ◽  
Vol 59 (1) ◽  
pp. 100-105 ◽  
Author(s):  
Lubomira M. Cabelkova-Taguchi ◽  
John Warkentin
Keyword(s):  
Transition State ◽  
Solvent Effects ◽  
Charge Separation ◽  
Substituent Effects ◽  
Activation Parameters ◽  
Oxidative Cyclization ◽  
First Order ◽  
Temperature Range ◽  
Aryl Amine ◽  
First Order Kinetics

A series of 5,5-dimethyl-4-aryl-Δ1-1,2,4-triazolin-3-ones (Ar = C6H5, p-C6H4CH3, p-C6H4OCH3, p-C6H4Cl, and p-C6H4Br) were prepared from the corresponding 4-arylsemicarbazones of acetone by oxidative cyclization on alumina. The triazolinones decompose in solution to N2, CO, and isopropylidene aryl amine, with first order kinetics, in the temperature range 148–200 °C. Average activation parameters are ΔH≠ = 35 kcal mol−1 and ΔS≠ = 8 cal K−1 mol−1. Substituent effects are correlated through σ-constants but the thermolyses are relatively insensitive to substituents, with ρ = −0.17 at 172.5 °C. Solvent effects indicate a transition state that is less polar than the ground state.It is tentatively concluded that the triazolinone fragmentation, like the analogous thermolysis of a Δ3-1,3,4-oxadiazolin-2-one, may be a fully-concerted but nonsynchronous process with a transition state involving little, if any, charge separation. Other mechanisms, except for those involving highly polar (e.g. zwitterionic) transition states, have not been ruled out.

Theoretical study on substituent and solvent effects for nanocubes formed with gear-shaped amphiphile molecules

2017 ◽  
Vol 19 (2) ◽  
pp. 1627-1631 ◽  
Author(s):  
T. Mashiko ◽  
S. Hiraoka ◽  
U. Nagashima ◽  
M. Tachikawa
Keyword(s):  
Molecular Dynamic ◽  
Solvent Effects ◽  
Theoretical Study ◽  
Molecular Dynamic Simulations ◽  
Aqueous Methanol ◽  
Dynamic Simulations ◽  
The Stability

We have carried out molecular dynamic simulations to elucidate the stability of hexameric gear-shaped amphiphile nanocube capsules in water, 25% aqueous methanol, and methanol.

On the Calculation of Transition State Activity Coefficient and Solvent Effects on Chemical Reactions

1998 ◽  
Vol 63 (12) ◽  
pp. 1969-1976 ◽  
Author(s):  
Alvaro Domínguez ◽  
Rafael Jimenez ◽  
Pilar López-Cornejo ◽  
Pilar Pérez ◽  
Francisco Sánchez
Keyword(s):  
Activity Coefficient ◽  
Transition State ◽  
Chemical Reactions ◽  
Solvent Effects ◽  
Transition State Theory ◽  
Reaction Medium ◽  
State Theory ◽  
Precursor Complex ◽  
State Activity ◽  
Classical Transition

Solvent effects, when the classical transition state theory (TST) holds, can be interpreted following the Brønsted equation. However, when calculating the activity coefficient of the transition state, γ# it is important to take into account that this coefficient is different from that of the precursor complex, γPC. The activity coefficient of the latter is, in fact, that calculated in classical treatments of salt and solvent effects. In this paper it is shown how the quotients γ#/γPC change when the reaction medium changes. Therefore, the conclusions taken on the basis of classical treatments may be erroneous.

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