The regioselective synthesis of both 2-and 3-alkoxyindoles from a common intermediate, 2-alkoxy-3-bromoindolines (ROBIN), is described. The 2-alkoxyindoles are obtained by a base-promoted regioselective elimination of HBr from ROBIN, whereas the synthesis of 3-alkoxyindoles is achieved by a silvermediated alkoxylation followed by an acid-promoted elimination of alkoxide. This key elimination features the complete regioselectivity and no need for catalysts, that makes it have potential synthetic applications. Furthermore, this protocol is user friendly because ROBIN is able to be prepared from commercially available indoles and is a bench-stable easy-to-handle crystalline substrate, thus allowing the concise synthesis of a variety of both 2-and 3-alkoxyindoles.
Wires and networks of Si quantum dots (QDs) with a length of over 1 μm and a width of ∼30 nm are produced by bridging Si QDs with metal ions in solution. It is shown that the width of the wires is almost independent of the preparation parameters and is always about 30 nm, except for the case when Si QDs larger than 30 nm are used, while the length of the wires depends strongly on the kinds of ions, the amount of ions and the amount of Si QDs in a solution. In addition to the microscopic size assemblies, macroscopic size rods of Si QDs with a width of ∼20 μm are produced by using Zn2+ ions. The XPS analyses reveal that Si QDs are connected to each other via a ZnO layer in the rod. The rods have much higher conductivity and photo-response than Si QD solids produced without metal ions.
This study investigated the structure and phase transition behaviour of a dynamic water nanotube cluster (WNT) confined within hydrophilic 1D nanochannels. We demonstrated that the WNT has a three-layered hydrate structure stabilized by hydrogen bonds with carboxylate groups in the outer channel walls. Moreover, it exhibits a pre-melting state that was attributed to the presence of metastable structures. Interestingly, the dynamic WNT structure was maintained even in the melting state because the multi-layered water cluster was stabilized in the hydrophilic nanoporous channel. To our knowledge, such a dynamic three-layered WNT structure is unique and rare because most WNTs are regarded as disordered water clusters. Therefore, we constructed another dynamic WNT using [RuIII(H2bim)3]3+ (H2bim = 2,2′-biimidazole) and a new organic spacer, 1,3,5-triazine-2,4,6-tricarboxylate (TATC3−). The dynamic WNT cluster has been identified for the crystal structure and heat properties.
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