Search Results (6)

This review explores the pervasive role of water in generating, storing, and mediating electric charge across natural and artificial systems. Far from being a passive medium, water actively participates in electrostatic and electrochemical processes through its intrinsic ionization, interfacial polarization, and charge separation mechanisms. The Maxwell–Wagner–Sillars (MWS) effect is presented as a unifying framework explaining charge accumulation at air–water, water–ice, and water–solid interfaces, forming dynamic “electric mosaics” across Earth’s environments. The authors integrate diverse phenomena—triboelectricity, hygroelectricity, hydrovoltaic effects, elastoelectricity, and electric-field-driven phase transitions—showing that ambient water continually shapes the planet’s electrical landscape. Electrostatic shielding by humid air and hydrated materials is described, as well as the spontaneous electrification of sliding or dripping water droplets, revealing new pathways for clean energy generation. In addition, the review highlights how electric fields and interfacial charges alter condensation, freezing, and chemical reactivity, underpinning discoveries such as microdroplet chemistry, “on-water” reactions, and spontaneous redox processes producing hydrogen and hydrogen peroxide. Altogether, the paper frames water as a universal electrochemical medium whose interfacial electric imprint influences atmospheric, geological, and biological phenomena while offering novel routes for sustainable technologies based on ambient charge dynamics and water-mediated electrification. Full article

Caffeic acid phenethyl ester (CAPE) is a phenolic natural product with a wide range of biological activities, including anticancer activity; however, the ester group of CAPE is metabolically labile. The corresponding amide, CAPA, has improved metabolic stability but limited anticancer activity relative to CAPE. We report the synthesis using flow and on-water Wittig reaction approaches of five previously reported and five novel CAPA analogues. All of these analogues lack the reactive catechol functionality of CAPA and CAPE. Cytotoxicity studies of CAPE, CAPA, and these CAPA analogues in HeLa and BE(2)-C cells were carried out. Surprisingly, we found that CAPA is cytotoxic against the neuroblastoma BE(2)-C cell line (IC₅₀ = 12 µM), in contrast to the weak activity of CAPA against HeLa cells (IC₅₀ = 112 µM), and the literature reports of the absence of activity for CAPA against a variety of other cancer cell lines. One novel CAPA analogue, 3f, was identified as having cytotoxic activity similar to CAPE in HeLa cells (IC₅₀ = 63 µM for 3f vs. 32 µM for CAPE), albeit with lower activity against BE(2)-C cells (IC₅₀ = 91 µM) than CAPA. A different CAPA analogue, 3g, was found to have similar effects against BE(2)-C cells (IC₅₀ = 92 µM). These results show that CAPA is uniquely active against neuroblastoma cells and that specific CAPA analogues that are predicted to be more metabolically stable than CAPE can reproduce CAPA’s activity against neuroblastoma cells and CAPE’s activity against HeLa cells. Full article

Radical reactions in water or aqueous media are important for organic synthesis, realizing high-yielding processes under non-toxic and environmentally friendly conditions. This overview includes (i) a general introduction to organic chemistry in water and aqueous media, (ii) synthetic approaches in, on, and with water as well as in heterogeneous phases, (iii) reactions of carbon-centered radicals with water (or deuterium oxide) activated through coordination with various Lewis acids, (iv) photocatalysis in water and aqueous media, and (v) synthetic applications bioinspired by naturally occurring processes. A wide range of chemical processes and synthetic strategies under different experimental conditions have been reviewed that lead to important functional group translocation and transformation reactions, leading to the preparation of complex molecules. These results reveal how water as a solvent/medium/reagent in radical chemistry has matured over the last two decades, with further discoveries anticipated in the near future. Full article

The use of eco-compatible synthetic procedures in organic reactions and, in particular, in 1,3-dipolar cycloaddition reactions, has recently received a great deal of attention and considerable progress has been achieved in this area in the last years. This review summarizes the approaches currently employed to synthesize heterocyclic compounds by catalyzed 1,3-dipolar cycloadditions in green solvents in the last six years. Our choice to do a selection of the literature from 2014 to 2019 was made considering the absence of a recent review about this period, to our knowledge. Several examples to construct heterocycles by 1,3-dipolar cycloadditions will be discussed in this work subdivided in function of the most important class of non-conventional and green solvents, i.e., ionic liquids (ILs), deep eutectic solvents (DES), and water. Full article

A versatile and practical “on-water” protocol was newly developed to synthesize quinazolinones using o-bromobenzonitrile as a novel starting material. Studies have found that air as well as water plays an important role in synthesis of quinazolinones. Further investigation indicated that dihydroquinazolinones can be prepared with this protocol under the protection of N₂. The protocol can be extended to other substrates and various quinazolinones and dihydroquinazolinones were obtained. o-Bromobenzamide, o-aminobenzonitrile, and o-aminobenzamide were also evaluated as starting materials, and the results further proved the versatility of this protocol, especially towards dihydroquinazolinones. Full article

Even if water is the natural environment for bioorganic reactions, its use in organic chemistry is often severely limited by the high insolubility of the organic derivatives. In this review, we introduce some examples of the use of water to perform organoselenium chemistry. We mainly discuss the advantages of this medium when the recyclability is demonstrated and when the water can control the selectivity of a reaction or enhance the reaction rate. Full article