The synthesis and characterization of the first examples of singly and doubly fused expanded porphyrins containing dithienothiophene (DTT) cores are reported.

In recent years, solid-state fluorescent materials have received much attention in diverse fields, such as fluorescent biological labels, sensors, and light-emitting diodes.[1] Many conjugated organic luminophores are highly emissive in dilute solutions, however, when fabricated into thin films, they suffer an aggregation-caused quenching (ACQ) effect, which limits their practical applications.[1] To solve this problem, recently, some organic molecules, which show an intense emission in the aggregated state, whereas they exhibit almost no or weak emission in dilute solutions, were reported. This unique phenomenon is widely researched as aggregation-induced emission (AIE) [2] and aggregation-induced enhanced emission (AIEE).[3] However, the potential utility of this phenomenon has not been explored in macrocycles. On the other hand, molecular sensors for Hg II ions have received considerable attention due to the extremely toxic impact exerted by Hg II on our environment. [4] Many efforts have been made to design various chemosensors specific to Hg II ions.[5] The major challenges involved in the creation of Hg II sensors are lack of selectivity and specificity. Calixphyrins, polypyrrolic macrocycles, are known for the coordination chemistry, [6] but reports on metal-ion sensing are very rare. Herein, we wish to report the AIEE characteristic of a calixbenzophyrin-derivative, M-1, and utilize this novel property for probing Hg II ions both in aqueous solution and in the solid state.The syntheses of calixbenzophyrins are outlined in Scheme 1. The synthetic methodology followed here is basically an acid-catalyzed condensation reaction. Stirring a solution of 1 [7] with pentafluorobenzaldehyde in dichloromethane in the presence of trifluoroacetic acid (TFA) followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted in calix[n]-m-benzo[m]phyrins (n = 2,3,4; m = 4,6,8) in 20 % (M-1), 10 % (M-2), and 5 % (M-3) yield, respectively. All the macrocycles were fully characterized by electronic, FAB-MS, and NMR spectral studies, and the structure of M-1 was finally confirmed by single-crystal Xray-diffraction analysis.[8] All the derivatives are soluble in common organic solvents, but insoluble in water.A solution of M-1 in dilute acetonitrile shows an absorption band at 434 nm, which arises from the p-p* transition of the dipyrrin moiety.[8] The emission spectrum shows a band at 539 nm. We observed an anomalous behavior in the emission spectrum of M-1 upon addition of various percentages of water (0-90 %), upon which the band at 539 nm is intensified with a bathochromic shift to 550 nm (Figure 1, left). Because water is not a good solvent for M-1, addition of water promotes efficient calixphyrin self-aggregation, which enhances the emission; in other words, M-1 is AIEE active. The trajectory of the intensity change suggests that the molecularly dissolved M-1 starts to congregate at a water fraction of 50 % and the population of the aggregate continues to increase as the water fraction increases fr...

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Poly(ethylene oxide) based electrolytes comprising LiCF 3 SO 3 and calix[2]-p-benzo[4]pyrrole (CBP) as anion binder were prepared and subjected to DSC, ionic conductivity, cationic transport number and FTIR analyses. Symmetric cells of the type Li/PEOþLiCF 3 SO 3 þCBP/Li were assembled with these electrolytes and evolution of interfacial resistance as a function of time was analyzed. The cationic transference number, t C although it improves the interfacial properties. FTIR study revealed the formation of Li-C compounds on the lithium surface upon contact with the CBP added membranes. The CBP added PE was found to be optimal in terms of ionic conductivity and transport number, t þ Li , above 70 C, which were found to be higher for a system previously reported with calix[6]pyrrole.

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