A multistimuli responsive and self-healing Zn(ii)–inosine supramolecular metal–organic gel: phase selective gelation and application as a light-responsive Schottky barrier diode

Abstract

Utilization of naturally available biomolecules such as nucleosides with several coordination sites as organic counterparts for the synthesis of multifunctional self-assembled metal–organic gels is important, considering the time and efforts required for the design of organic ligands that can coordinate to metal ions, forming a gel. In the present work, inosine, a simple nucleoside has been utilized as a ligand for the generation of a supramolecular metallo-hydrogel through coordination with Zn²⁺ ions in the presence of NaOH. Several spectroscopic, microscopic and rheological investigations have been performed to characterize the formed gel. The obtained metallo-hydrogel is transparent, and the transparency can be tuned depending on the amount of NaOH used. The Zn–inosine metal–organic gel exhibits several functional properties such as self-healing, stimuli responsiveness, thixotropy, and injectability. Furthermore, the freeze-dried Zn–inosine xerogel exhibited selective gelation of water, which has been utilized to separate water from mixtures that include organic solvents (or oils) and water. The semiconducting characteristics of the Zn–inosine metallogel have been used for device fabrication based on the Schottky diode interface between a semiconductor and metal. The fabricated device was found to be photo-responsive in nature and exhibited better device parameters when illuminated with light. The present results are anticipated to lead to the development of newer soft materials constructed using simple biomolecules for environmental and electronic applications.