DFT Study of the Reaction Mechanism of N-(Carbomylcarbamothioyl) Benzamide.

Felix Odame

doi:10.17344/acsi.2017.4001

Abstract

The reaction mechanism for the formation of N-(carbomylcarbamothioyl)benzamide has been successfully computed with the B3LYP/6-31g(d) functional and basis set and compared with 1H NMR monitoring of the progress of the reaction with time. The reaction is proposed to proceed through two transition states: Ts1 (the rate-determining step) with highly unstable species (with a requisite orientation for the reaction to proceed), and Ts2 with a lower energy leading to the product. Computation of the reaction pathway was also carried out using the B3PW91/6-31G(d), M06/6-31G(d) and Wb97XD/6- 31G(d) functionals and basis set. These results do not present a clear reaction pathway compared to that given by the B3LYP/6-31G(d).

Highlights

The use of Density functional theory (DFT) in computation in most branches of chemistry over the years has been extensive,[1,2,3] and various methods have been used in that regard,[4,5,6,7,8] the methods used include local density approximation (LDA), generalized gradient approximation (GGA), meta GGA, hybrid GGA, hybrid-meta GGA, and double-hybrid GGA, various empirical corrections such as dispersion, have been successfully implemented in many popular computational codes
In this work we present the computed reaction mechanism and the DFT transition state studies of the formation of N-(carbomylcarbamothioyl) benzamide, the transition states that contribute to the formation of products as well as the intermediates in the reaction pathway have been computed and discussed
The predicted reaction pathway proceeds by the coming together of urea and benzoyl isothiocyanate (I1), it was obtained by optimising the starting material to a minimum and tracing the reverse intrinsic reaction coordinate (IRC) path of the transition state TS1

Summary

Introduction

The use of Density functional theory (DFT) in computation in most branches of chemistry over the years has been extensive,[1,2,3] and various methods have been used in that regard,[4,5,6,7,8] the methods used include local density approximation (LDA), generalized gradient approximation (GGA), meta GGA, hybrid GGA, hybrid-meta GGA, and double-hybrid GGA, various empirical corrections such as dispersion, have been successfully implemented in many popular computational codes. The mechanisms for the oxidation of thiophene by OH radicals under inert conditions (Ar) have been studied using density functional theory in conjunction with various exchange-correlation functionals.[15] A density functional theory (DFT) study has been performed to explore the mechanisms of the acid catalyzed decarboxylation reaction of salicylic acids using the B3LYP method with 6-31++G(d,p) basis set in both gas phase and aqueous environment.[16] Density functional theory (DFT) has been used to study the cobalt(I)-catalyzed enantioselective intramolecular hydroacylation of ketones and alkenes Hydrogen migration was both the rate determining and chirality-limiting step, and this step was endothermic. In this work we present the computed reaction mechanism and the DFT transition state studies of the formation of N-(carbomylcarbamothioyl) benzamide, the transition states that contribute to the formation of products as well as the intermediates in the reaction pathway have been computed and discussed

Computational Details

Results and Discussion

HOMO-LUMO Analysis

Conclusion