Conformational polymorphism and thermochemical analysis of 5,5‴-Bis[(2,2,5,5-tetramethyl-1-aza-2,5-disila-1-cyclopentyl)ethyl]-2, 2′:5′,2″:5″,2‴-quaterthiophene

Hitoshi Muguruma, Shu Hotta

研究成果: Article

1 引用 (Scopus)

抜粋

The titled compound exists as two polymorphic solid phases (denoted form-I and form-II). Form-I obtained by as-synthesized material is a more stable phase. Form-II is a less stable phase. Spontaneous solid-solid transformation from form-II to form-I is observed in the temperature range between room temperature and the melting point of form-I (Tm = 156.5°C), and its activation energy is estimated to be 96 kJ mol-1 by Arrhenius plot. The solid-solute-solid transformation (recrystallization from solution) from form-II to form-I is also observed. In contrast, form-II is obtained only by a solid-melt-solid transformation from form-I. Therefore, the system of two polymorphs is monotropic. The solid-state NMR measurement shows that form-I has the molecular conformation of complete S-syn-anti-syn in the oligothiophene backbone, whereas form-II has that of S-all-anti. With the solution NMR data, the polymorphism could not be observed. Therefore, the polymorphs originate from the different molecular packing involving the conformational change of the molecule. This unique property is attributed to the extra bulky terminal groups of the compounds. However, despite the extra bulky terminal groups, the mentioned polymorphism is not observed in the titled compound analogue which has S-all-anti conformation (like form-II).

元の言語English
ページ(範囲)23075-23080
ページ数6
ジャーナルJournal of Physical Chemistry B
110
発行部数46
DOI
出版物ステータスPublished - 2006 11 23

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

フィンガープリント Conformational polymorphism and thermochemical analysis of 5,5‴-Bis[(2,2,5,5-tetramethyl-1-aza-2,5-disila-1-cyclopentyl)ethyl]-2, 2′:5′,2″:5″,2‴-quaterthiophene' の研究トピックを掘り下げます。これらはともに一意のフィンガープリントを構成します。

  • これを引用