scholarly journals Evaluation of Electronic Effects in the Solvolyses ofp-Methylphenyl andp-Chlorophenyl Chlorothionoformate Esters

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Malcolm J. D’Souza ◽  
Olivia N. Hampton ◽  
Brett M. Sansbury ◽  
Dennis N. Kevill
Keyword(s):  
Rate Data ◽  
Electronic Effects ◽  
Titration Method ◽  
Organic Mixtures

The solvolyses ofp-tolyl chlorothionoformate andp-chlorophenyl chlorothionoformate are studied in a variety of organic mixtures of widely varying nucleophilicity and ionizing power values. This solvolytic data is accumulated at 25.0°C using the titration method. An analysis of the rate data using the extended (two-term) Grunwald-Winstein equation and the concept of similarity of substrates based on theirl/mratios shows the occurrence of simultaneous side-by-side addition-elimination and unimolecularSN1 mechanisms.

Electrophilic additions to allenes. VI. The role of steric versus electronic effects in the reactions of arenesulphenyl halides with allenes

1980 ◽  
Vol 58 (24) ◽  
pp. 2737-2744 ◽  
Author(s):  
Dennis G. Garrattz ◽  
Pierre L. Beaulieu
Keyword(s):  
Positive Charge ◽  
Steric Effects ◽  
Rate Data ◽  
Electronic Effects ◽  
Rate Determining Step ◽  
Minimal Importance ◽  
Electrophilic Additions

The role of steric and electronic effects during the rate and product determining steps for the addition of arenesulphenyl chlorides to 1,3-disubstituted allenes has been briefly examined. Both effects appear to be generally of minimal importance during the rate determining step. The available rate data indicate the presence of little, if any, build up of positive charge on sulphur. These results are interpreted in terms of an SN2 attack on bivalent sulphur leading to an alkylidenethiiranium ion intermediate. Steric effects are of greater importance in the product determining step, particularly when the sulphenyl chlorides possess two bulky ortho substituents, as in the case of 2,4,6-triisopropylbenzenesulphenyl chloride.

Electronic Effects of Aryl and Heteroaryl Groups on the Rate of Nucleophilic Displacement of Chlorine from 5-Heteroaryl(or Aryl)-2-chloropyrimidines by Piperidine

1980 ◽  
Vol 35 (4) ◽  
pp. 463-467 ◽  
Author(s):  
David W. Allen ◽  
David J. Buckland ◽  
Barrie G. Hutley
Keyword(s):  
Rate Data ◽  
Electronic Effects ◽  
Nucleophilic Displacement ◽  
Synthetic Routes ◽  
Kinetics Of

The kinetics of nucleophilic displacement of chlorine from a series of 2-chloro-5-heteroaryl( or aryl)pyrimidines by piperidine have been studied in order to assess the electronic effects of the 5-substituent. The observed order of reactivity is 5-(1-methylpyrrol-2-yl) < 5-p-anisyl < 5-p-tolyl < 5-phenyl < 5-(2-thienyl) < 5-(2-furyl) < 5-(m-chlorophenyl). The reactions are enthalpy-controlled and the rate data can be explained as a consequence of the electron-withdrawing or electron-donating ability of the 5-substituent. Synthetic routes to the compounds studied are also described.

Electronic Effects of Aryl and Heteroaryl Groups on the Rate of Quaternization of 5-Aryl(or Heteroaryl)pyrimidines

1980 ◽  
Vol 35 (4) ◽  
pp. 468-470 ◽  
Author(s):  
David W. Allen ◽  
David J. Buckland ◽  
Barrie G. Hutley
Keyword(s):  
Substituent Effects ◽  
Phenacyl Bromide ◽  
Rate Data ◽  
Electronic Effects ◽  
Kinetics Of

The kinetics of quaternization of a series of 5-aryl- and 5-heteroarylpyrimidines with phenacyl bromide in acetonitrile have been studied in order to assess the electronic effects of the 5-substituent. The observed order of reactivity is 5-(1-methylpyrrol-2-yl) > 5-panisyl >5-(2-furyl) >5-p-tolyl > 5-(2-thienyl) >phenyl > 5-(m-chlorophenyl). The reactions are enthalpy controlled and the rate data can be accounted for in terms of the electronwithdrawing or donating ability of the 5-substituent. The substituent effects of the 2-fury 1- and 2-thienyl groups in the above reaction are significantly different from those observed in the piperidinolysis of 2-chloro-5(2-heteroaryl)pyrimidines.

Correlation in the heart rate data

1998 ◽  
Vol 2 ◽  
pp. 141-148
Author(s):  
J. Ulbikas ◽  
A. Čenys ◽  
D. Žemaitytė ◽  
G. Varoneckas
Keyword(s):  
Nonlinear Dynamics ◽  
Experimental Data ◽  
Heart Rate ◽  
Time Series ◽  
Cardiovascular Function ◽  
Statistical Properties ◽  
Rate Data ◽  
Heart Rate Data ◽  
Dynamical Nature ◽  
Analysis Of Time Series

Variety of methods of nonlinear dynamics have been used for possibility of an analysis of time series in experimental physiology. Dynamical nature of experimental data was checked using specific methods. Statistical properties of the heart rate have been investigated. Correlation between of cardiovascular function and statistical properties of both, heart rate and stroke volume, have been analyzed. Possibility to use a data from correlations in heart rate for monitoring of cardiovascular function was discussed.

High rate data systems

1987 ◽  
Author(s):  
RICHARD MILLER ◽  
DAVID NICHOLS
Keyword(s):  
High Rate ◽  
Rate Data ◽  
Data Systems

On the Crystal Chemistry of Inorganic Nitrides: Crystal-Chemical Parameters and Opportunities in the Exploration of Their Compositional Space

2020 ◽  
Author(s):  
Olivier Charles Gagné
Keyword(s):  
Functional Properties ◽  
A Priori ◽  
Lone Pair ◽  
Length Variation ◽  
Electronic Effects ◽  
Statistical Knowledge ◽  
Redox Active ◽  
Multiply Bonded ◽  
Jahn Teller ◽  
Compositional Space

The scarcity of nitrogen in Earth’s crust, combined with challenging synthesis, have made inorganic nitrides a relatively-unexplored class of compounds compared to their naturally-abundant oxide counterparts. To facilitate exploration of their compositional space via <i>a priori</i> modeling, and to help <i>a posteriori</i> structure verification not limited to inferring the oxidation state of redox-active cations, we derive a suite of bond-valence parameters and Lewis-acid strength values for 76 cations observed bonding to N<sup>3-</sup>, and further outline a baseline statistical knowledge of bond lengths for these compounds. We examine structural and electronic effects responsible for the functional properties and anomalous bonding behavior of inorganic nitrides, and identify promising venues for exploring uncharted compositional spaces beyond the reach of high-throughput computational methods. We find that many mechanisms of bond-length variation ubiquitous to oxide and oxysalt compounds (e.g., lone-pair stereoactivity, the Jahn-Teller and pseudo Jahn-Teller effects) are similarly pervasive in inorganic nitrides, and are occasionally observed to result in greater distortion magnitude than their oxide counterparts. We identify inorganic nitrides with multiply-bonded metal ions as a promising venue in heterogeneous catalysis, e.g. in the development of a post-Haber-Bosch process proceeding at milder reaction conditions, thus representing further opportunity in the thriving exploration of the functional properties of this emerging class of materials.<br>

Sign in / Sign up

Export Citation Format

Share Document