標題: In Situ Ultralow-Frequency Raman Tracking of the Polymorphic Transformation of Crystalline 1,1 '-Binaphthyl
作者: Chang, Chun-Fu
Wang, Szu-Cheng
Shigeto, Shinsuke
應用化學系
Department of Applied Chemistry
公開日期: 6-二月-2014
摘要: Extremely low-frequency (LF) Raman spectroscopy that allows for fast access to lattice vibrations with little hindrance of immense Rayleigh scattering was used to track in situ thermally induced polymorphic transformation of crystalline 1,1'-binaphthyl (BN), a fundamental structural unit of specific chiral ligands. BN occurs in two conformational polymorphs, cisoid and transoid forms, with the former being a racemate and the latter being a conglomerate of chiral crystals. Observed LF Raman spectra (from 200 cm(-1) down to similar to 5 cm(-1), equivalent to 0.15 THz), which arise predominantly from lattice vibrations, show markedly different features between the cisoid and transoid forms, making it possible to study their phase transition. A series of LF Raman spectra measured with slow heating of microcrystalline BN reveal that, in contrast to previous studies, the monoclinic cisoid form transforms directly to the tetragonal transoid form in the solid state without formation of any intermediate phase. The present approach is applicable to various phase transition systems, including pharmaceutical compounds, liquid crystals, and polymer films, which conventional X-ray diffraction analysis may not be able to investigate.
URI: http://dx.doi.org/10.1021/jp410941t
http://hdl.handle.net/11536/23795
ISSN: 1932-7447
DOI: 10.1021/jp410941t
期刊: JOURNAL OF PHYSICAL CHEMISTRY C
Volume: 118
Issue: 5
起始頁: 2702
結束頁: 2709
顯示於類別:期刊論文


文件中的檔案:

  1. 000331153700053.pdf