• Bulletin of the Korean Chemical Society
• /
• v.32 no.3
• /
• pp.768-778
• /
• 2011

Calixpyrroles and related macrocycles are non-planer synthetic anion receptors that have attracted considerable attentions in recent years. Although the synthesis of calix[4]pyrrole (known as meso-octamethylporphyrinogen) was reported more than 100 years ago, the anion binding properties were first discovered in 1996. The simple calix[4]pyrroles can be synthesized in single step in high yield by condensation of pyrrole with acetone. The compounds showed preferential binding for halide anions including fluoride, phosphate, carboxylate, and chloride in organic media. Efforts to improve the anion affinity of calix[4]pyrrole and to enhance its selectivity have led to the synthesis of a variety of new calixpyrrole derivatives. Among the various modifications, introduction of straps on one side of the calix[4]pyrroles are the most effective. Incorporation of aromatic rings other than pyrroles also exhibited interesting binding behaviour. Introduction of signalling units as part of the strapping element enable to detect the anions on chromogenic or fluorogenic fashion. Finding of the anion transport properties across the membrane and cytotoxic effects of the calix[4]pyrroles open new window for calixpyrrole-related research. The polymer-incorporated systems have also been employed as anion complexants in solvent-solvent extraction. These old, yet easy-to-make macrocycles have well advanced more recently with the discovery of the ion-pair complexation properties. In this review, the synthetic developments and anion binding properties of calixpyrroles for the last decades will be discussed and will cover the advances in calixpyrrole chemistry.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.11
• /
• pp.2782-2784
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• v.34 no.1
• /
• pp.283-286
• /
• 2013

• Journal of Sensor Science and Technology
• /
• v.30 no.6
• /
• pp.357-363
• /
• 2021

We developed a chemiresistive anion sensor using highly conductive carbon nanotube fibers (CNTFs) functionalized with anion receptors. Mechanically robust CNTFs were prepared via wet-spinning utilizing the nematic liquid crystal properties of CNTs in chlorosulfonic acid (CSA). For anion detection, polymeric receptors composed of dual-hydrogen bond donors, including thiourea 1, squaramide 2, and croconamide 3, were prepared and bonded non-covalently on the surface of the CNTFs. The binding affinities of the anion receptors were studied using UV-vis titrations. The results revealed that squaramide 2 exhibited the highest binding affinity toward AcO^-, followed by thiourea 1 and croconamide 3. This trend was consistent with the chemiresistive sensing responses toward AcO^- using functional CNTFs. Selective anion sensing properties were observed that CNTFs functionalized with squaramide 2 exhibited a response of 1.08% toward 33.33 mM AcO^-, while negligible responses (<0.1%) were observed for other anions such as Cl^-, Br^-, and NO₃^-. The improved response was attributed to the internal charge transfer of dual-hydrogen bond donors owing to the deprotonation of the receptor upon the addition of AcO^-.

• Molecules and Cells
• /
• v.38 no.7
• /
• pp.657-662
• /
• 2015

Rapid and efficient engulfment of apoptotic cells is an essential property of phagocytes for removal of the large number of apoptotic cells generated in multicellular organisms. To achieve this, phagocytes need to be able to continuously uptake apoptotic cells. It was recently reported that uncoupling protein 2 (Ucp2) promotes engulfment of apoptotic cells by increasing the phagocytic capacity, thereby allowing cells to continuously ingest apoptotic cells. However, the functions of Ucp2, beyond its possible role in dissipating the mitochondrial membrane potential, that contribute to elevation of the phagocytic capacity have not been determined. Here, we report that the anion transfer or nucleotide binding activity of Ucp2, as well as its dissipation of the mitochondrial membrane potential, is necessary for Ucp2-mediated engulfment of apoptotic cells. To study these properties, we generated Ucp2 mutations that affected three different functions of Ucp2, namely, dissipation of the mitochondrial membrane potential, transfer of anions, and binding of purine nucleotides. Mutations of Ucp2 that affected the proton leak did not enhance the engulfment of apoptotic cells. Although anion transfer and nucleotide binding mutations did not affect the mitochondrial membrane potential, they exerted a dominant-negative effect on Ucp2-mediated engulfment. Furthermore, none of our Ucp2 mutations increased the phagocytic capacity. We conclude that dissipation of the proton gradient by Ucp2 is not the only determinant of the phagocytic capacity and that anion transfer or nucleotide binding by Ucp2 is also essential for Ucp2-mediated engulfment of apoptotic cells.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.spc8
• /
• pp.2891-2892
• /
• 2011

• Bulletin of the Korean Chemical Society
• /
• v.25 no.9
• /
• pp.1411-1413
• /
• 2004

• Bulletin of the Korean Chemical Society
• /
• v.24 no.10
• /
• pp.1538-1540
• /
• 2003

• Bulletin of the Korean Chemical Society
• /
• v.28 no.5
• /
• pp.851-854
• /
• 2007

• Bulletin of the Korean Chemical Society
• /
• v.28 no.9
• /
• pp.1531-1534
• /
• 2007

Anion receptor based on 2-imidazolidone molecular scaffold has been synthesized. Anion binding studies carried out using 1H NMR and UV?vis spectroscopy revealed that this receptor 6 displays selectivity for the for the oxyanions such as acetate and dihydrogenphosphate ions and the affinity for the anions simply reflects the basicity of anions.