The annual number of cancer deaths continues increasing every day; thus, it is urgent to search for and find active, selective, and efficient anticancer drugs as soon as possible. Among the available anticancer drugs, almost all of them contain heterocyclic moiety in their chemical structure. Xanthone is a heterocyclic compound with a dibenzo-γ-pyrone framework and well-known to have “privileged structures” for anticancer activities against several cancer cell lines. The wide anticancer activity of xanthones is produced by caspase activation, RNA binding, DNA cross-linking, as well as P-gp, kinase, aromatase, and topoisomerase inhibition. This anticancer activity depends on the type, number, and position of the attached functional groups in the xanthone skeleton. This review discusses the recent advances in the anticancer activity of xanthone derivatives, both from natural products isolation and synthesis methods, as the anticancer agent through in vitro, in vivo, and clinical assays.

Environmental pollution and global warming cause serious problems in human life. Since the demand for our human daily appliances had been increased by years, the organic chemical-based industries response that demand increment by increasing their production process. Because of that, the environmental pollution becomes worse and worse. Green chemistry thus was introduced to influence the chemical industries to strive for better environmental sustainability. Over 20 years, green chemistry principles have to influence the organic chemistry field especially as many researchers have put their attention on that field of research. So far, synthesis process involving organic compounds has been considered on waste prevention, safer solvents, design for high energy efficiency, and usage of renewable feedstocks. This review comprehensively discusses in brief about the implementation of green chemistry principle and their applications in the synthesis process of organic compounds.

C-3-nitrophenylcalix[4]resorcinarene (calix-3NO2) is a macrocyclic compound with phenolic and nitrobenzene moieties and thus, promising to make a stable complex with a certain metal ion. Due to their high economic value for advanced materials, the detection of rare earth metals such as La(III) ions gains significant attention. In this work, we employed the calix-3NO2 to establish a simple detection technique for La(III) ions using an ultraviolet (UV) spectrophotometer. The calix-3NO2 was obtained in 40% yield through a condensation reaction between resorcinol and 3-nitrobenzaldehyde in acidic condition. It was confirmed that the calix-3NO2 was able to detect La(III) ions in water:methanol media (4:1 v/v) by giving a significant additional peak at 268 nm due to charge transfer between ligand and metal ions. Furthermore, the calix-3NO2 had selectively bound to La(III) ions compared with other metal ions such as Al(III), Ba(II), Ca(II), Cu(II), Mg(II), Mn(II), Ni(II), Zn(II), K(I), and Na(I). These findings are important in the design of an organic probe used for sensitive detection of La(III) ions using a simple UV spectroscopic technique.

Calixarenes are well-known supramolecular host molecules with versatile applications. Over the past decades, hundreds of selective and sensitive detections of several analytes have been reported by employing calixarenes as the chemosensor agent. The detection and quantification of metal ions and anions are crucial as heavy metal ions are harmful to living organisms, while monitoring anions is pivotal in the environmental samples. On the other hand, detecting and quantifying biomolecules and neutral molecules are critical due to their irreplaceable role in human health. In this review, we summarized the application of calixarenes as the supramolecular chemosensor agent for detecting metal ions, anions, biomolecules, and neutral molecules through fluorescent spectroscopy to give brief information on the design and development of the chemosensor field. This review updates the world with the application of calixarene derivatives as fluorescent chemosensors and challenges researchers to design and develop better chemosensor agents in the future.

Chemosensors with ultrasensing capabilities for detection of metal ions have received particular attention when using luminescent organic compounds. Even though hundreds of chemosensor agents have been reported for Fe3+ ion sensing, the designs of those molecules have been complicated and time consuming, in addition to having limited application for aquatic samples due to their poor hydrophilicity. Here, we synthesized a novel azo‐imine derivative (L2) that showed ultrasensitive and selective sensing for Fe3+ ions. L2 exhibited ultraselective detection of Fe3+ ions with a turn‐off of its emission intensity at 341 nm in H2O:MeOH (4:1 v/v) aqueous medium. This quenching phenomenon was in good agreement with its colour change from orange‐yellowish to colourless. Its capability was shown due to its very low limit of detection and limit of quantification values of 0.31 and 1.04 μM, respectively. The interference study showed that L2 is ultraselective for the detection of Fe3+ ions without a significant reduction in its sensing capability even in competitive metal mixtures. Furthermore, direct Fe3+ quantification of tap and drinking water showed that L2 gave good recovery percentages. These findings demonstrated that the Schiff’s base with an azo fluorophore derivative is a potential chemosensor agent for Fe3+ ions sensing applications in aqueous media.

Nitro-substituted C-phenylcalix [4]resorcinarene derivatives were synthesized and evaluated for gold(III) ions adsorption. All the nitro-substituted C-phenylcalix[4]resorcinarenes showed higher maximum adsorption capacity as compared to the bare C-phenylcalix[4]resorcinarene. A remarkable high adsorption capacity of up to 272.70 mg g À 1 was obtained after 2 h on the C-2-nitrophenylcalix[4]resorcinarene (Calix-2NO 2 ), which was two times higher than that of the C-phenylcalix [4] resorcinarene. The adsorption capacity was affected by the position of the nitro group. The highest adsorption capacity observed on the Calix-2NO 2 was closely related to the strongest supramolecular interactions between the gold(III) ions and the Calix-2NO 2 , as supported by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance ( 1 H-NMR) spectroscopies as well as the desorption study. This study demonstrated that the macrocyclic material, namely nitro-substituted C-phenylcalix[4]resorcinarenes, were effective adsorbents having good reusability, and thus, applicable for gold(III) ions recovery.

Chitosan is one of the naturally abundant, biodegradable, and low-cost adsorbent materials for metal adsorption purposes. In this work, we evaluated the application of chitosan materials derived from seafood wastes in Depok beach, Yogyakarta, for an effective recovery of the palladium(II) ions. First of all, the seafood wastes were treated to obtain chitin and then followed by the deacetylation process to produce chitosan material with a deacetylation degree of 78.42%. The chitosan material was characterized using Fourier transform infrared (FTIR) spectrophotometer. It was found that chitosan gave high adsorption percentage (90%) for palladium(II) ions due to the complexation with hydroxyl, amino and carbonyl functional groups. The palladium(II) adsorption onto chitosan material followed the pseudo-second-order (R2 = 0.9978) and Langmuir (R2 = 0.9979) models for kinetic and isotherm experiments, respectively, with a maximum adsorption capacity value of 0.70 mmol g-1. The palladium(II) ions could be easily desorbed in 90% percentage using 1.0 M HCl solution from metal-laden chitosan to regenerate the adsorbent material. The chitosan-based adsorbent material did not lose its adsorption capability after three consecutive cycles with no significant structural change as revealed from the FTIR data. These results showed the potential application of natural chitosan materials derived from seafood wastes for the effective recovery of palladium(II) ions.

Zinc titanate (Zn2Ti3O8) is a bimetal oxide material that is especially attractive as a photocatalyst. In the preparation of the Zn2Ti3O8, the calcination temperature is a crucial parameter. Hence, in the present work, we aimed to synthesize the Zn2Ti3O8 materials from zinc(II) nitrate and titanium(IV) isopropoxide as precursors by using a sol-gel method and followed by calcination at 700, 900, and 1100 °C to give ZT-700, ZT-900, and ZT-100 materials, respectively. The ZT materials were characterized using Fourier transform infrared (FTIR), diffuse reflectance ultraviolet-visible (DR UV-vis), and fluorescence spectroscopies. It was confirmed that the ZT materials contained O−Ti−O, Zn−O−Ti, Zn−O, Ti−O−Ti, and Ti−O functional groups as shown from their FTIR spectra. Similar fluorescence properties were only observed on the ZT-700 and ZT-900. From the bandgap energy analysis, ZT-700 and ZT-900 contained spinel and cubic Zn2Ti3O8 (spl-Zn2Ti3O8 and c-Zn2Ti3O8) crystal phases), while ZT-1100 contained c-Zn2TiO4 and TiO2 rutile crystal phases. The kinetic analysis of photocatalytic phenol degradation showed that both ZT-700 and ZT-900 materials exhibited high photocatalytic activity with the reaction rate constants of 0.0353 and 0.0355 h−1, respectively. These values were higher than that of the ZT-1100 (0.0206 h−1). This study demonstrated that calcination at 700 and 900 °C resulted in the formation of the spl-Zn2Ti3O8 and c-Zn2Ti3O8 phases, which were effective as the photocatalyst, but the formation of c-Zn2TiO4 and rutile TiO2 at calcination of 1100 °C deteriorated the photocatalytic activity. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).