Alkanes versus Oligosilanes: Conformational Effects on σ-Electron Delocalization
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388963%3A_____%2F22%3A00551652" target="_blank" >RIV/61388963:_____/22:00551652 - isvavai.cz</a>
Result on the web
<a href="https://doi.org/10.1021/jacs.1c10616" target="_blank" >https://doi.org/10.1021/jacs.1c10616</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/jacs.1c10616" target="_blank" >10.1021/jacs.1c10616</a>
Alternative languages
Result language
angličtina
Original language name
Alkanes versus Oligosilanes: Conformational Effects on σ-Electron Delocalization
Original language description
Observations and computations both suggest that the extent and the conformational dependence of σ-electron delocalization in frontier molecular orbitals are quite different in alkanes CnH2n+2 and oligosilanes SinH2n+2, the isosteric and isoelectronic saturated chains built from carbon or silicon atoms, respectively. We find that the different conformational effects can be understood in simple intuitive terms. There are two modes of σ-electron delocalization, strongly conformation-sensitive skeletal delocalization through backbone X–X bonds (σ-conjugation and σ-hyperconjugation) and only weakly conformation-sensitive lateral delocalization through lateral X–H bonds (σ-hyperconjugation and σ-homoconjugation). In alkanes, both modes are active and complement each other, leading to delocalization in all conformations. In oligosilanes, only skeletal delocalization of holes is important in frontier orbitals, and the even simpler ladder C model provides an adequate intuitive description of the strong conformational dependence of σ-electron delocalization. Ultimately, the difference is primarily due to the similar electronegativity of carbon and hydrogen as opposed to the lower electronegativity of silicon, which causes a polarization of Si–H bonds. This understanding has been derived from an analysis of approximate algebraic solutions of a simple Hückel-level extended ladder H model for an infinite regular helical chain, using the effective mass of a hole as a measure of delocalization. This model is derived from the classical Sandorfy H model, and is parametrized by fitting to results of density functional or Hartree–Fock theory.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10401 - Organic chemistry
Result continuities
Project
—
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2022
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of the American Chemical Society
ISSN
0002-7863
e-ISSN
1520-5126
Volume of the periodical
144
Issue of the periodical within the volume
1
Country of publishing house
US - UNITED STATES
Number of pages
15
Pages from-to
463-477
UT code for WoS article
000739358000001
EID of the result in the Scopus database
2-s2.0-85122701754