Intriguing interactions of triazolyl organosilane with copper (II) ion, blue copper protein, and silica nanoparticles: Spectral and theoretical approach

Abstract

In this manuscript, a concise library of 2‐Amino‐4‐chlorophenol‐based organosilanes 5(a‐c) was designed and synthesized by employing a multistep strategy and characterized with the help of NMR (1H and 13C) spectroscopic and mass spectrometry techniques. The silica nanoparticles loaded with 5a have been successfully synthesized and confirmed with the help of various techniques. Further, the interaction of probes 5a and its hybrid silica nanoparticles (A‐NPs) have been investigated towards various metal ions and exhibited favorable selectivity towards Cu2+ ions over other common metal ions in methanol with both colorimetric and fluorimetric read‐outs. The binding of probes 5a and A‐NPs with Cu2+ can be monitored by change of color in daylight and also by turn‐off fluorescence response in UV light. The sensing mechanism is ascribed to paramagnetic nature of Cu2+ ion leading to ligand to metal charge transfer and, hence, shows chelation enhanced fluorescence quenching (CHEQ) effect in the vicinity of ligands 5a and A‐NPs. The results demonstrated that the hybrid nanocomposites (A‐NPs) has even lower limit of detection and higher binding affinity as compared to probe 5a. The possible mechanism of 1:1 binding of 5a with Cu2+ could be substantiated by the density functional theory. Thus, this facile and appropriate sensing strategy may serve as a promising tool for selective and sensitive detection of Cu2+ ions. Moreover, the molecular docking studies provide valuable information regarding the interaction of compound 5a with the blue copper protein (plastocyanin). Hence, the current investigation provides a new avenue to design more potent organosilane analogs.