Rhodamine appended thiacalix[4]arene of 1,3-alternate conformation for nanomolar detection of Hg2+ ions

Rhodamine appended thiacalix[4]arene receptors 4 and 5 are synthesized, of which receptor 4 of 1,3-alternate conformation shows high selectivity towards Hg2+ ions with fluorescence enhancement among various metal ions tested and thus, behaves as an efficient ‘Turn On’ fluorescent chemosensor for Hg2+ ions with a detection limit up to nanomolar range.