New tripodal and dipodal colorimetric sensors for anions based on tris/bis-urea/thiourea moieties

作者：Bhardwaj Vimal K; Sharma Sanyog; Singh Narinder; Hundal Maninder Singh; Hundal Geeta^*

来源：Supramolecular Chemistry, 2011, 23(12): 790-800.

DOI：10.1080/10610278.2011.593629

• 1,3,5-trimethyl/triethyl benzene core
• urea/thiourea binding units
• H-bonding
• deprotonation
• anion sensing

Seven neutral tripodal and dipodal receptors having mesitylene/triethylbenzene as core moiety, urea/thiourea as binding groups and p-nitrobenzene as signalling unit have been reported. The receptors act as selective colorimetric, naked eye sensors for small and spherical F- ion with some interference from tetrahedral H2PO4- ions. Thiourea derivatives form stable 1: 1 H-bonded complexes with F- anion and to some extent with H2PO4- anions, whereas for urea derivatives, the recognition is simply based on acid-base reaction between ureidic protons and basic F- ions and is a completely reversible phenomenon. The pre-organisation of thiourea derivatives coupled with their high-intrinsic acidity is supposed to help them in the formation of strong H-bonded complexes with F- anion. The urea-based receptors do not respond at lower concentrations of the anion, but at higher concentrations, they undergo completely reversible deprotonation concomitant with a colorimetric change, with the production of stable [HF2](-) anion.

• 出版日期2011