Probing the Reaction of N,N-Dimethyformamide Dimethyl Acetal with p-tert-Butylthiacalix[4]arene Tetrahydrazides: A Facile Approach for the Synthesis and Application of Novel Metal Receptors

Abstract

Recent developments in the field of sensing and recognition revealed that artificial receptors based on calix[4]arenes with pi-conjugated fluorophoric or chromophoric moieties are efficient in enhancing selectivity/sensitivity as well as the binding affinity for ionic or molecular recognition. Herein, via studying the reaction of dimethylformamide dimethyl acetal (DMF-DMA) with p-tert-butylthiacalix[4]arene tetrahydrazides in three different conformers (i.e., cone, partial-cone, and 1,3-alternate), the formation of novel lower rim p-tert-butylthiacalix[4]arene derivative (cone, partial-cone, and 1,3-alternate) conformers in high yields (80, 95, and 85%, respectively) was achieved. The structure of isolated products was confirmed using different spectroscopic and analytical techniques such as FT-IR, H-1 NMR, C-13 NMR, and elemental analysis. Importantly, the synthesized receptors showed preferential uptakes of alkali (Na+, K+ and Cs+), heavy (Pb2+, Cd2+, Hg2+, and Ag+) and transition (Ni2+, Co2+, and Cu2+) metal ions via liquid-liquid extraction method. The finding of this work adds new compounds to the growing family of thiacalix[4]arenes and validates their high sensitivity and selectivity in detection of heavy metal ions.