The construction of helicate metal-organic nanotubes and enantioselective recognition

Intriguing 1D single-walled metal-organic nanotubes (MONTs) Zn 2 (RR-CHCAIP)Py 2 (H 2 O) ( HMOF-2 ) were successfully self-assembled using a semirigid homochiral ligand, 5,5′-((1 R ,2 R )-cyclohexane dicarbonyl bis(azanediyl)) diisophthalic acid ( RR-CHCAIP ) with zinc salt, which was constructed from an organic ligand similar to the twin blades of a propeller with the Zn 2 (COO) 4 (H 2 O)(Py) 2 cluster acted as the SBU, and the terminal pyridine auxiliary ligand capping at the Zn atoms played a key role in the formation of the 1D single nanotubes. The fluorescence of the HMOF-2 emulsion could be effectively quenched by d / l -lactic acid, d / l -tartaric acid enantiomers and d / l -alanine via hydrogen bonding interactions with the inwall of MONTs, which suggested this to be a remarkable chiral sensor for α-hydroxyl carboxylic acid and amino acid enantiomers with good sensitivity and enantioselectivity. Comparatively, HMOF-2 showed a negligible response towards d / l -mandelic acid and d / l -tyrosine, which chiefly arose from the confinement effect and the host-guest interaction of MONTs with the analytes. The construction strategy of MONTs based on the homochiral propeller-like ligand that bridges two metallic pillars will open new perspectives for developing self-assembling chiral MONTs with unique and practically useful enantioselective functions. Self-assembling metal-organic nanotubes ( HMOF-2 ) acts as an excellent fluorescence sensor for fast, convenient, sensitive and enantioselective recognition of d / l -tartaric acid and d - or l -lactic acid with adverse properties in the food industry.