Supramolecular non-symmetric dimers derived from cholesterol: synthesis and phase transitional properties

ABSTRACT

Three series of novel dimeric supramolecules, possessing both inter- as well as intramolecular H-bonding, have been prepared and investigated for their thermal properties. They were obtained in excellent yields by condensing cholesteryl ω-(3-hydroxy-4-formylphen-oxy)alkanoates with 4-(n-alkoxy)benzohydrazides, 3,4-bis(n-decyl-oxy)benzohydrazide and 3,4,5-tris(n-decyloxy)benzohydrazide. The influence of increase in the number of terminal n-alkoxy tails from one to three and the length and parity of the flexible spacer on phase transitional behaviour have been thoroughly investigated with the aid of microscopic, calorimetric and X-ray diffraction (XRD) techniques. The results of these complementary studies clearly illustrate the dependence of thermal behaviour of the dimers on these structural factors. The rigid intermolecular association via H-bonds through complementary benzohydrazide component enforce their self-assembly into frustrated and polar smectic phases; H-bond force coupled with the bulkiness of steroid moiety affects the electrical switching property of this fluid polar structure.

Graphical Abstract

KEYWORDS:

• H-Bonds
• supramolecular
• dimers
• ferroelectric behaviour
• frustrated phases

Acknowledgements

She also thanks Prof G. U Kulkarni, Dr Praveer Asthana, Prof K. A. Suresh and Dr S. Krishna Prasad for their support and encouragement.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

USH expresses her profound appreciation and gratitude to DST, New Delhi, Govt. of India, for providing financial support through the WOS-A scheme, No. SR/WOS-A/CS-48/2013(G).