New eco-friendly 1-alkyl-3-(4-phenoxybutyl) imidazolium-based ionic liquids derivatives: a green ultrasound-assisted synthesis, characterization, antibacterial activity and POM analyses.

Mouslim Messali,Taibi Ben Hadda,Adeeb Al-Sheikh Ali,Wael El-Sayed,Mohamed Aouad,Belkheir Hammouti

doi:10.3390/molecules190811741

Abstract

In view of the emerging importance of the ILs as “green” materials with wide applications and our general interests in green processes, a series of a twenty five new 1-alkyl-3-(4-phenoxybutyl) imidazolium-based ionic liquids (ILs) derivatives is synthesized using a facile and green ultrasound-assisted procedure. Their structures were characterized by FT-IR, 1H-NMR, 13C-NMR, 11B, 19F, 31P, and mass spectrometry. Antimicrobial screens of some selected ILs were conducted against a panel of Gram-positive and Gram-negative bacteria. The antimicrobial activity of each compound was measured by determination of the minimal inhibitory concentration (MIC) yielding very interesting and promising results. Their antibacterial activities are reported, and, on the basis of the experimental and virtual POM screening data available, attempt is also made to elucidate the structure activity relationship.

Highlights

Over the past two decades, Ionic liquids (ILs) have attracted considerable attention as friendly environmental substitutes for volatile organic solvents due to the several unique properties such as negligible vapor pressure, high thermal stability, easy recyclability, no flammability, and high ionic conductivity [1,2,3,4]
In continuation of our previous work dealing with the development of novel room temperature functionalized ionic liquids [37], we report the synthesis of a variety of new imidazolium-based ionic liquids under both conventional and ultrasound irradiation methods (Schemes 1 and 2)
Chemical shifts (δ) were reported in ppm to a scale calibrated for tetramethylsilane (TMS), which is used as an internal standard

Summary

Introduction

Over the past two decades, Ionic liquids (ILs) have attracted considerable attention as friendly environmental substitutes for volatile organic solvents due to the several unique properties such as negligible vapor pressure, high thermal stability, easy recyclability, no flammability, and high ionic conductivity [1,2,3,4]. ILs are a group of low-melting-point salts containing organic cation, such as imidazolium, pyrrolidinium, or pyridazinium, paired with various anions, such as bromide or tetrafluoroborate [5] Due to these unique properties, ILs have been widely synthesized and investigated as media for electrodeposition of metals [6,7,8], as a tool for lignocellulosic biomass fractionation [9], catalysis and biocatalysis [10,11,12,13,14,15,16], corrosion inhibition [17,18,19,20], food chemical science [21], and the nuclear industry [22]. The use of these green technologies leads to many advantages, such as large reductions in reaction times, enhancements in conversions, sometimes in selectivity [24,25,26,27]

Objectives

Methods

Results

Conclusion