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Zaitsev BA. Quantitative Estimate of the Resonance Effects in Some Unsaturated, Monocyclic,
and Aromatic Hydrocarbons Based on the Renewed Optical Exaltations. CURR ORG CHEM 2022. [DOI: 10.2174/1385272825666211126143032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
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The present review discusses a new viewpoint on refractometry as the oldest experimental
physical method, whose scientific potential in the estimation of structural effects in
organic chemistry has been missed so far. The author demonstrates that upon certain adjustment
and redesign of refractometry, this potential can be tapped and successfully used to determine
a type of π-electron interaction, delocalization degree of π-electrons in organic compounds,
and to perform quantitative estimates of resonance effects in unsaturated, (polycyclic)
aromatic, and other polyconjugated systems (e.g., fullerenes). The method for accurate separation
of molar refraction into additive and constitutive components was suggested; the method
is based on the specially developed additive scheme. It was revealed that the negative deviations
from additivity for cycloalkanes depend linearly on the number of carbon atoms in the
ring. Excellent linear correlations between renewed optical exaltations, the number of π-electrons in a conjugated
system, and experimentally found resonance energy (determined from hydrogenation heat values) were demonstrated.
Angular coefficients of the correlation series (ρ-constants) are considered as a criterion of classification, which
characterizes the degree of mobility of π-electrons in the conjugated system of a given type. It is emphasized that
the development of methods for precise measurement of the constitutive components of molar refraction may become
a useful additional source of information about resonance and other effects in organic and polymer chemistry.
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Affiliation(s)
- Boris A. Zaitsev
- Department of Chemistry, Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 St. Petersburg, Russia
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Zaitsev BA. Estimate of Hyperconjugation Strength in Alkylaromatics and Unsaturated Hydrocarbons Derived from Refractometric Data. CURR ORG CHEM 2020. [DOI: 10.2174/1385272823666191108100747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
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A retrospective view of exaltation of refraction observed for many unsaturated
and aromatic compounds demonstrates that this physical phenomenon is undeservedly
considered only as a qualitative measure of conjugation. This mini-review discusses numerous
papers by the author that have been published earlier in inaccessible periodicals
and collections of scientific papers. Using a great number of illustrations, the author shows
that this parameter can be successfully used for quantitative estimate of resonance effects
in organic and polymer chemistry. The methods for derivation of strictly additive atomic
and group refraction constants are described; these constants were subsequently used as a
tool that allowed quantitative estimation of resonance effects in mono-, di-, tri- and polyalkylbenzenes,
alkylnaphthalenes, some alkyl derivatives of unsaturated hydrocarbons.
These effects cause strictly fixed increase in refraction of carbon atoms in different structural modifications
(graphene, fullerene, diamond) and in polycyclic aromatic hydrocarbons. The relevant results regarding quantitative
estimation of degree of steric inhibition of resonance in sterically hindered ortho-dialkylbenzenes, 1,2,3-
trialkyl-, 1,2,3,4-tetraalkyl-, and 1,2,3,4,5-polyalkylbenzenes accumulated by the author are summarized.
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Affiliation(s)
- Boris A. Zaitsev
- Department of Chemistry, Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 St. Petersburg, Russian Federation
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Plummer EL, Seiders RP, Seelye DE, Stewart RR. Pyrethroid insecticides derived from 2,2′ -bridged biphenyl-3-ylmethanols. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780150513] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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