TY - JOUR

T1 - 2,1,3-Benzochalcogenadiazoles

T2 - Regularities and peculiarities over a whole chalcogen pentad O, S, Se, Te and Po

AU - Pritchina, Elena A.

AU - Gritsan, Nina P.

AU - Rakitin, Oleg A.

AU - Zibarev, Andrey V.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - With DFT calculations, compared where possible with experimental data, molecular and electronic structure of the title compounds 1-5 (chalcogen=O, S, Se, Te and Po, respectively) and their radical ions was studied towards identification of regularities and peculiarities over a whole chalcogen pentad. Calculated properties of neutral molecules covered their geometries, atomic charges, bond orders and QTAIM descriptors, shapes and energies of π-MOs, ionization energy and electron affinity, NICSs, and MEPs; and those of radical ions included geometries, shapes and energies of π-SOMOs, electron spin density distributions, hyperfine coupling constants and g factors. In the most cases uniform patterns were obtained featuring only some particular peculiarities regarded to a certain chalcogen. The most important findings embrace reduced aromaticity of the heterocycles of 4 and 5 (NICS) and enlarged electrostatic contribution to their X-N bonds (QTAIM; X=Te, Po) as compared with 1-3. However, the ground-state patterns are not enough to explain known differences in heteroatom reactivity of the title compounds. It is suggested that the differences come mainly from reaction kinetics and thermodynamics where widely varied atomic dipole polarizability of the chalcogens should be essentially important.

AB - With DFT calculations, compared where possible with experimental data, molecular and electronic structure of the title compounds 1-5 (chalcogen=O, S, Se, Te and Po, respectively) and their radical ions was studied towards identification of regularities and peculiarities over a whole chalcogen pentad. Calculated properties of neutral molecules covered their geometries, atomic charges, bond orders and QTAIM descriptors, shapes and energies of π-MOs, ionization energy and electron affinity, NICSs, and MEPs; and those of radical ions included geometries, shapes and energies of π-SOMOs, electron spin density distributions, hyperfine coupling constants and g factors. In the most cases uniform patterns were obtained featuring only some particular peculiarities regarded to a certain chalcogen. The most important findings embrace reduced aromaticity of the heterocycles of 4 and 5 (NICS) and enlarged electrostatic contribution to their X-N bonds (QTAIM; X=Te, Po) as compared with 1-3. However, the ground-state patterns are not enough to explain known differences in heteroatom reactivity of the title compounds. It is suggested that the differences come mainly from reaction kinetics and thermodynamics where widely varied atomic dipole polarizability of the chalcogens should be essentially important.

KW - RADICAL-ANION SALTS

KW - PHOTOELECTRON-SPECTRA

KW - ELECTRONIC-STRUCTURE

KW - REDOX PROPERTIES

KW - COMPLEXES

KW - VALENCE

KW - CHARGE

KW - 2,1,3-BENZOTHIA(SELENA)DIAZOLES

KW - 2,1,3-BENZOTHIADIAZOLE

KW - BENZOSELENADIAZOLE

UR - http://www.scopus.com/inward/record.url?scp=85078483090&partnerID=8YFLogxK

U2 - 10.17374/targets.2020.23.143

DO - 10.17374/targets.2020.23.143

M3 - Article

AN - SCOPUS:85078483090

VL - 23

SP - 143

EP - 154

JO - Targets in Heterocyclic Systems

JF - Targets in Heterocyclic Systems

SN - 1724-9449

ER -