Pyrophosphate Sensing by a Fluorescent Zn²⁺Bound Triazole Linked Imino-Thiophenyl Conjugate of Calix[4]arene in HEPES Buffer Medium: Spectroscopy, Microscopy, and Cellular Studies

Abstract

An in situ prepared Zn(2+) complex of triazole linked imino-thiophenyl conjugate of calix[4]arene, [ZnL], was demonstrated to be highly fluorescent in HEPES buffer solution. [ZnL] has been used as a chemo-sensing ensemble for the recognition of phosphates in general and pyrophosphates in particular among the eighteen different anions studied. The chemo-sensing behavior of the [ZnL] has been demonstrated through fluorescence, absorption, visual fluorescent color changes, ESI MS, and (1)H NMR titrations. Variations in the microstructural features of L, its zinc complex and the complex upon addition of PPi have been demonstrated through atomic force microscopy and transmission electron microscopy. Such studies have been extended to see the permeability of the conjugate into the HeLa cells by fluorescence microscopy. In accession, a reversible "write-read-erase-read" logic gate property of L has been demonstrated through a feedback loop in the presence of Zn(2+) and PPi.

Tetraphenylethene based zinc complexes as fluorescent chemosensors for pyrophosphate sensing

“…The solvent was removed under reduced pressure; the crude product was purified by silica gel column eluting with EtOAc/PE (2:1, v/v) to give the product as a pale yellow solid (500 mg), yield 57.9%. 1 The yellow solid achieved above (450 mg, 0.551 mmol) was dissolved in a saturated of HCl-methanol solution (100 mL) and stirred overnight at room temperature. The solvent and excess HCl were removed under reduced pressure, giving a yellow solid.…”

“…Freeze-dried the solution to remove water and obtained the product as a pale yellow cottonlike solid (260 mg), yield 91%. 1 …”

“…Phosphate-based inorganic and organic molecules play important roles in biological processes such as energy storage, signal transduction and DNA sequencing [1][2][3][4][5]. Therefore, developing synthetic receptors for recognition and sensing of such anions have drawn much attention.…”

“…The solvent was evaporated under reduced pressure to give the yellow solid. The solid was washed with ethanol (5Â 5 mL) and the mixture was centrifuged to afford the pure product as white solid (65 mg), yield 43% 1. H NMR (400 MHz, DMSO-d 6 ): d 7.13-7.11 (m, 11H), 7.02-6.95 (m, 8H), 4.59 (s, 2H), 4.49 (s, 1H), 3.76 (s, 2H), 2.99 (br, 2H), 2.77-2.57 (br, 11H); 13 C NMR (100 MHz, DMSO-d 6 ): d 143.7, 143.5, 143.4, 143.3, 141.5, 140.5, 131.1, 130.3, 128.4, 128.3, 128.2, 127.1; ESI-HRMS: m/z calcd.…”

One-Pot Click Access to a Cyclodextrin Dimer-Based Novel Aggregation Induced Emission Sensor and Monomer-Based Chiral Stationary Phase

“…The Cu(I) catalytic cycloaddition between terminal alkyne and azide (CuAAC) has become the prime click reaction type for not only modularly linking functional units but also synthesizing the triazole moiety which is an important coordinating precursor [10,11,12,13]. Our previous efforts have been dedicated to the use of CuAAC to fabricate structurally well-defined CD-based chiral stationary phases (CD-CSPs).…”