New fluorogenic dansyl-containing calix[4]arene in the partial cone conformation for highly sensitive and selective recognition of lead(II)

The design of a new highly efficient lead(II)-selective optical chemosensor for detection of [Pb.sup.2+] at the levels as low as 2.5 ppb, is described. The sensor was obtained by covalent attachment of two pendent proton-ionizable dansylcarboamide groups to the calix[4]arene preorganized in the partial cone conformation.