Estimation of anisotropic parameters in liquid crystals using a constant time NMR method

Abstract

A method for measurement of anisotropic parameters like ¹H chemical shifts and the estimation of ¹H chemical shift anisotropy (CSA) in liquid crystals is presented. The estimation of ¹H CSA is essential in order to understand the structural information of several systems like membrane proteins, organic and biological solids. After obtaining the information of chemical shifts in the liquid crystalline phase, alignment-induced shifts (AIS) are calculated. The dependence of AIS values and the local order parameters and CSA can be utilized to calculate the ¹H CSA liquid crystals. The advantage with proton chemical shifts is that, it is sensitive not only to local structural details but also to the inter-molecular interactions. This could be an advantage in the study of systems like solids and liquid crystals.

Keywords:

• Thermotropic liquid crystal
• solid state NMR
• chemical shift anisotropy
• order parameters
• alignment-induced chemical shifts