CuInS2 nanorods and networks are interesting candidates for applications requiring efficient charge transport, such as solar energy conversion, because of the increased electrical conductivity in elongated or interconnected nanocrystals, compared to isolated, quasi-spherical ones. However, little is known about the growth mechanisms involved in the formation of this kind of nanostructures, yet. Here, CuInS2 nanorods and networks were synthesized through a facile low-cost and phosphine-free method. Copper and indium sources were added together in the presence of oleylamine and oleic acid. Changing the amount of oleic acid present in the reaction solution influenced the reactivity of the monomers, and consequently, the size of copper sulfide seeds formed in situ after the injection of tert-dodecanethiol, serving as the source of sulfur. Two different growth mechanisms of CuInS2 nanorods were observed, depending on the size of the copper sulfide seeds. Larger seeds (8 nm), which were generated with relatively small amounts of oleic acid, resulted in the formation of hybrid copper sulfide-copper indium disulfide nanocrystals as intermediates in the growth process of the nanorods, while smaller seeds (4 nm) obtained with relatively large amounts of oleic acid were gradually converted to copper indium sulfide nanorods. At longer reaction times, these nanorods formed network structures. The reaction between oleylamine and oleic acid at high temperature turned out to be the crucial factor to induce the attachment of nanorods to multipods and networks.
Using in vitro hydroxyl radical-scavenging and quinone reductase-inducing assays, bioactivity-guided fractionation of an ethyl acetate-soluble extract of the fruits of the botanical dietary supplement, black chokeberry (Aronia melanocarpa), led to the isolation of 27 compounds, including a new depside, ethyl 2-[(3,4-dihydroxybenzoyloxy)-4,6-dihydroxyphenyl] acetate (1), along with 26 known compounds (2-27). The structures of the isolated compounds were identified by analysis of their physical and spectroscopic data ([α](D), NMR, IR, UV, and MS). Altogether, 17 compounds (1-4, 9, 15-17, and 19-27) showed significant antioxidant activity in the hydroxyl radical-scavenging assay, with hyperin (24, ED(50) = 0.17 μM) being the most potent. The new compound (1, ED(50) = 0.44 μM) also exhibited potent antioxidant activity in this assay. Three constituents of black chokeberry fruits doubled quinone reductase activity at concentrations <20 μM, namely, protocatechuic acid [9, concentration required to double quinone reductase activity (CD) = 4.3 μM], neochlorogenic acid methyl ester (22, CD = 6.7 μM), and quercetin (23, CD = 3.1 μM).
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