Spectroscopic and Colorimetric Studies for Anions with a New Urea-Based Molecular Cleft

Sanchita Kundu,Md Alamgir Hossain,Zehra Yousuf,Tochukwu Kevin Egboluche

doi:10.3390/chemosensors9100287

Abstract

A new simple urea-based dipodal molecular cleft (L) has been synthesized and studied for its binding affinity for a variety of anions by 1H-NMR, UV-Vis and colorimetric techniques in DMSO-d6 and DMSO, respectively. The results from titration studies suggest that the receptor forms a 1:2 complex with each of the anions used via hydrogen bonding interactions and exhibits strong selectivity for fluoride among halides, showing the binding affinity in the order of fluoride > chloride > bromide > iodide; meanwhile, it displays moderate selectivity for acetate among oxoanions, showing the binding affinity in the order of acetate > dihydrogen phosphate > bicarbonate > hydrogen sulfate > nitrate. Colorimetric studies of L for anions in DMSO reveal that the receptor is capable of detecting fluoride, acetate, bicarbonate and dihydrogen phosphate, displaying a visible color change in the presence of the respective anions.

Highlights

Anions are ubiquitous in nature and play an important role in biology, medicine, catalysis, agriculture and in many other industries [1,2,3,4]
We have synthesized a simple urea-based dipodal neutral receptor functionalized with a para-xylyl-based molecular framework as a spacer along with two functionalized with a para-xylyl-based molecular framework as a spacer along with two nitro groups signaling units studied its binding affinity a wide variety of aninitro groups as as signaling units andand studied its binding affinity for afor wide variety of anions ons in solution
> nitrate in DMSO, providing theproviding highest binding for binding for acetate over other anions studied

Summary

Introduction

Anions are ubiquitous in nature and play an important role in biology, medicine, catalysis, agriculture and in many other industries [1,2,3,4]. Halides and oxoanions are essential in many biological processes that are key components in life to properly function for growth, reproduction and genetic signaling [5]. When the concentration of anions becomes higher than the normal permissible range, they may adversely affect both biological systems as well as the environment. The presence of an excess phosphate in the environment leads to eutrophication [9,10] of natural water bodies deteriorating normal aquatic life. A high level of phosphate in the human body increases the risk of hyperparathyroidism [5], soft tissue calcification, cardiovascular complications [11] and crystal deposition disease [12]

Methods

Results

Conclusion