A phenol-based compartmental ligand as a potential chemosensor for zinc(ii) cations

an "end-off"-type compartmental lewis base, 2,6-bis(2-hydroxybenzyl-2-hydroxyethylamino)methyl-4-methylphenol (l), was synthesized as a potential chemosensor for zn2+ ions. l coordinates two zn2+ cations in methanol-water solution, forming a dinuclear complex whose formulation was confirmed by esi-ms spectroscopy and job's plot. the fluorescence of l is remarkably enhanced by zn2+ as compared with k+, ca2+, mg2+, cu2+, pb2+, mn2+, fe3+, fe2+, co2+, cd2+ and ni2+ ions. the fluorescence enhancement is attributed to the complexation of zn2+ with l, which interrupts the photoinduced electron transfer process and rigidifies the molecular skeleton of l. the fluorescence of l is greatly dependent on the acidity and polarity of the solvents. this compound may be used as a probe to sense zn2+ ion in polar protic solvents after proper modification.