BINOL and triazole-containing Janus rings and 29-8-29-membered tricyclic ladder-type hybridized siloxane: application in the fluorescence sensing of anions.

Tetrachloro- and tetraazide-substituted all- cis -tetraphenylcyclotetrasiloxanes (all- cis -T 4 ) 2 and 3 were synthesized in high yields and were fully characterized. Then the precursor 3 underwent CuAAC click reaction with monopropargyl BINOL 4 and dipropargyl BINOL 6 to give the novel BINOL and triazole-containing all- cis -T 4 cyclic siloxane 5 and the 29-8-29-membered-ring ladder-type hybrid siloxane 7. The sensing ability of compounds 5 and 7 towards anions was studied as well, and it was observed that 7 could selectively recognize iodides through synergistic C-H⋯I hydrogen bonding, resulting in an impressive fluorescence quenching with a K sv of 8.10 × 10 4 M -1 .