Quantum-chemical approach to the solvatochromic transition in polysilane derivatives

Yuuichi Orimoto, Yuriko Aoki

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We approached the solvatochromic transition observed in polysilane derivatives (poly[bis(4-propoxybutyl)silylene] (PPBS)) from the standpoint of various quantum chemical treatments. It was found from conventional geometry optimizations at the levels of semiempirical and ab initio molecular orbital methods that a protonation to polysilane oligomers with side chain R = -OCH 3 results in the conformational change of Si-backbone to a trans-zigzag structure. Using the Elongation method, which was developed for efficient calculations of huge systems, it was demonstrated that a protonation could change the conformation of Si-backbone to a trans-zigzag structure over 10-14 Si atoms. In addition, ab initio calculations showed that the positive charge of a proton can delocalize into the Si-backbone through a long side chain in PPBS. Positively charged polysilane oligomers provide a rotational barrier that prefers a trans-zigzag structure, whereas neutral oligomers have a barrier that results to a random structure. This unique behavior of the charged polysilane oligomers should not be disregarded in understanding the mechanism of the solvatochromic transition in PPBS. In ab initio configuration interaction/Møller-Plesset through-space/bond interaction analysis, it was found that such a unique behavior of the rotational barrier in polysilane oligomers could be explained by the effect of orbital delocalization through σ-conjugation on the Si-backbone.

Original languageEnglish
Pages (from-to)119-133
Number of pages15
JournalJournal of Polymer Science, Part B: Polymer Physics
Volume44
Issue number1
DOIs
Publication statusPublished - Jan 1 2006

Fingerprint

Polysilanes
polysilanes
oligomers
Oligomers
Derivatives
Protonation
Molecular orbitals
conjugation
configuration interaction
elongation
Conformations
Protons
Elongation
molecular orbitals
orbitals
Atoms
optimization
protons
Geometry
geometry

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Materials Chemistry

Cite this

Quantum-chemical approach to the solvatochromic transition in polysilane derivatives. / Orimoto, Yuuichi; Aoki, Yuriko.

In: Journal of Polymer Science, Part B: Polymer Physics, Vol. 44, No. 1, 01.01.2006, p. 119-133.

Research output: Contribution to journalArticle

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