Multiple photoluminescence from pyrene-fused hexaarylbenzenes with aggregation enhanced emission features

Multiple photoluminescence, involved in monomer emission, excimer emission and charge transfer emission origin from new pyrene-fused hexaarylbenzenes (HAB) compounds were observed, which were designed and synthesized (in high yield) via the Diels-Alder reaction of bis(2-tert-butylpyren-6-yl)acetylene and tetraphenylcyclopentadienone. Although the distinction of between two molecules arises only from the geometrical position of one of the pyrenes, the NMR spectra, the crystal packing and the physicochemical properties of these pyrene-based HAB hybrids are distinctly different both in their solution state and in aggregation-state. The X-ray diffraction analysis clearly indicated that the pyrene moieties in this system would form different crystal packing in crystal state that can induce a fantastic multiple photoluminescence phenomenon

Novel fluorinated benzimidazole-based scaffolds and their anticancer activity in vitro

A small library of twelve, structurally diverse, fluoroaryl benzimidazoles was prepared using a simple synthetic strategy employing SNAr reactions. This allowed rapid assembly of heterocyclic structures containing linked and tethered fluoroaryl benzimidazoles. X-ray crystal structures of seven compounds were obtained including those of two macrocyclic compounds containing 21- and 24-membered rings. Three tethered fluoroaryl benzimidazole derivatives demonstrated micromolar inhibition against K-562 and MCF-7 cell lines. These compounds, in addition to 1-tetrafluoropyrid-4-yl-2-tetrafluoropyrid-4-ylsulfanyl-1H-benzimidazole, also demonstrated micromolar inhibition against G361 and HOS cell lines. Two of the compounds were found to activate caspases leading to apoptosis

Thiacalix[4]arene derivatives bearing imidazole units: a ditopic hard/soft receptor for Na+ and K+/Ag+ with an allosteric effect and a reusable extractant for dichromate anions

Two novel receptors 5,11,17,23-tetra-tert-butyl-25,27-bis[(ethoxycarbonyl)methoxy]-26,28-bis-[1-methyl-(imidazole)meth-oxy]-2,8,14,20-tetra-thiacalix[4]arene (L1) and 5,11,17,23-tetra-tert-butyl-25,27-bis-[(benzyl)methoxy]-26,28-bis-[1-methyl-(imidazole)-methoxy]-2,8,14,20-tetrathiacalix[4]arene (L2) possessing imidazole moieties based on thiacalix[4]arene in the 1,3-alternate conformation have been synthesized and characterized. The crystal structures of L1 and L2 have been determined. The binding behaviour towards Li+, Na+, K+ and Ag+ ions has been examined by 1H NMR titration experiments in (CDCl3/CD3CN; 10:1, v/v) solution. The exclusive formation of mononuclear complexes of L1 with metal cations is of particular interest revealing a negative allosteric effect in the thiacalix[4]arene family. Liquid-liquid extraction experiments indicate that synthesized L2 can be utilized as an efficient reusable extractant for dichromate anion by controlling the pH of the aqueous solution