Highly selective and sensitive simultaneous nanomolar detection of Cs(i) and Al(iii) ions using tripodal organic nanoparticles in aqueous media: the effect of the urea backbone on chemosensing

Chemosensing plays a very important role in the detection of essential/pollutant ions in aqueous media. In this manuscript, two tripodal ligands,i.e., 1-(2-hydroxybenzyl)-3-(4-nitrophenyl)-1-phenylurea (ligand1) and 1-(2-hydroxybenzyl)-3-(4-nitrophenyl)-1-phenylthiourea (ligand2) have been synthesised, which differ in the linker molecule,i.e., urea and thiourea in ligand1and ligand2, respectively. The ligands were characterised by NMR, IR and mass spectroscopic techniques. Ligands1and2(2 mM) were further employed for the generation of their organic nanoparticles (ONPs) (0.01 mM) of size 20-25 nm and 30-35 nm, respectively, by the reprecipitation method. The chemosensing properties of1-ONP and2-ONP solutions were investigated.1-ONP showed simultaneous recognition behaviour towards Cs(i) and Al(iii) with the limits of detection of similar to 220 and similar to 377 nM, respectively, in an aqueous medium, while2-ONP did not show any recognition behaviour towards any ion.