An organic nanoporous polymer (BET surface area of 750 m(2) g(-1)) containing bicovalently-bonded Tröger's base as functional moieties in the network was synthesized, characterised, and further applied as a promising heterogeneous catalyst in the addition reaction of diethylzinc to aromatic aldehyde.
The synthesis and evaluation of a novel Schiff-base fluorescent probe L for detection of Al(3+) are described. The structure of L was determined by X-ray and other spectroscopic data. The fluorescent spectra changes and microscopy images show that indicator L is highly selective for Al(3+) not only in abiotic systems but also in living cells. Other metal ions failed to respond. The new probe could be used as an efficient tool for Al(3+) monitoring in the environment and biological systems.
An interesting aldehyde- and ketone-induced intermolecular tandem decarboxylation-coupling (Csp(3)-Csp) catalyzed by copper with use of natural alpha-amino acids as starting materials is developed under neutral conditions with the production of CO(2) and H(2)O as the only byproducts. Various functionalized nitrogen-containing compounds were obtained by this method. In these processes, interesting regioselectivites of the alkylation were observed, which has been rationalized by the relative stability of proposed resonance structures based on computation methods.
Enantiomerically pure tribenzotriquinacenes (TBTQs) bearing two monofunctionalized aromatic nuclei were synthesized for the first time and their optical properties and absolute configuration determined. A remarkably regioselective bis-formylation of the fully bridgehead methylated parent TBTQ hydrocarbon with MeOCHCl(2)/TiCl(4) afforded a mixture of two C(s)-symmetrical (achiral) difunctionalized derivatives together with one C(1)-symmetrical (chiral) isomer. Reduction and subsequent column chromatography furnished the three respective benzylic TBTQ dialcohols. Optical resolution of the racemic 2,6-bis(hydroxymethyl) derivative was achieved via the diastereomeric (R)-1,1'-bi-2-naphthol ethers and the absolute configuration of the enantiomers was determined by CD exciton model analysis. The electronic circular dichroism (ECD) spectra and the specific rotation of the enantiomers were found to agree with the results of DFT calculations. Among the C(s)-symmetrical isomers, the "proximal" 2,11-dialdehyde and the corresponding benzylic dialcohol were identified by 2D NMR spectroscopy and X-ray crystallographic analysis, respectively, and used as the starting point for the synthesis of several novel dithiametacyclophanes. These include the first "dimeric" tribenzotriquinacene-based cyclophanes bearing the bowls of the two TBTQ units attached to each other in a syn (concave-concave) or anti (convex-concave) configuration. The usefulness of such thiacyclophanes as fluorescent chemosensors for different metal ions is also demonstrated.
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