Home
Resources
Publications
Ultraviolet-visible-near Infrared and mid-Fourier Transform Infrared Spectroscopic Studies of Intermolecular Interaction in Cholesteryl Oleyl Carbonate in Mesophases

Ultraviolet-visible-near Infrared and mid-Fourier Transform Infrared Spectroscopic Studies of Intermolecular Interaction in Cholesteryl Oleyl Carbonate in Mesophases

P Das, R K Sinha, S Basu

J Chem Phys. 2006 Mar 28;124(12):124514.

PMID: 16599704

Abstract:

Ultraviolet-visible-near infrared (UV-Vis-NIR) and Fourier transform infrared (FTIR) spectroscopic studies are presented of molecular association between like molecules of cholesteryl oleyl carbonate, each containing suitable pi-donor (steroid ring C=C) and pi-acceptor (C-O single bonds united with a C=O bond to give a carbonate group) moieties. Frequency shifts and intensity enhancements of donor and acceptor oscillators appear to be governed by reduced mass, vibronic coupling constants, and a few other parameters such as relative change in force constants, etc. Donor-acceptor complex formation is characterized not only by the appearance of new bands in the mid-FTIR spectrum but also by the emergence of a new, intense electronic band centered at approximately 3700 cm(-1), the so-called charge-transfer band, in the UV-Vis-NIR spectrum. This band is strong in the smectic-A and solid phases, but progressively diminishes when temperature is raised to realize the upper end of the cholesteric phase and eventually the isotropic phase. Also, a new, small electronic band at approximately 360 nm, only seen in the entire thermal range of the cholesteric phase, is attributed to the Lifshitz-van der Waals interaction between pretransitional smectic-A domains existing in the cholesteric phase. It is argued that mesophases may owe their thermodynamic stability to both Lifshitz-van der Waals and vibronic coupling (or electron-phonon coupling in extended systems such as smectics and solids) interactions.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP17110519	Cholesteryl oleyl carbonate		17110-51-9	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: