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The first examples of silicon compoundsof 1,1-bis(pyrrol-2-yl)etheneshave been synthesized via salt metathesis from a 2-fold lithiateddipyrromethene and different diorganodichlorosilanes (i.e., dimethyldichlorosilane,diphenyldichlorosilane, and 1,1-dichlorosilacyclobutane). Herein wereport on their molecular structures, their optical properties, andsome reactivity patterns. [ABSTRACT FROM AUTHOR]

Chemical analysis of a marine-derived Streptomycessp. (CMB-M0423) isolated from beach sand off Heron Island, Australia, yielded three new members of the rare pyrroloterpene biosynthetic structure class. Identified by detailed spectroscopic analysis as the first reported examples of naturally occurring 2-nitropyrroles, heronapyrroles A−C (1−3) displayed promising biological activitywith low to submicromolar IC50activity against Gram-positive bacteria but no cytotoxicity toward mammalian cell lines. [ABSTRACT FROM AUTHOR]

Abstract: A novel method of synthesizing long-wavelength absorbing and emitting bis-trimethine dyes that consists of condensing benzodipyrrolenine dialdehyde with quaternized heterocyclic CH-acidic compounds was used to prepare a series of biscyanines. The new method is more convenient than its conventional counterepart, which relies upon condensation of a quaternized benzodipyrrolenine with Fisher''s aldehyde, for the synthesis of a symmetrically substituted dyes that contain various heterocyclic end-groups. Investigations of the spectral and luminescent properties of the dyes in solution revealed that the absorption (596–717 nm) and emission (629–773 nm) maxima of the biscyanines were red-shifted by ∼100 nm compared to the parent “monomeric” cyanine that contained only one chromophoric polymethine system. The prepared dyes have high extinction coefficients (≤251,000 M−1 cm−1) and quantum yield (≤28%). Substitution of both terminal benzoxazole moieties with indolenine, benzothiazole, 2- and 4-quinoline imparted a red-shift in the absorption and emission maxima but lowered quantum yield. [Copyright &y& Elsevier]

Abstract: Photoluminescence of a novel polypyrrole based on N-vinylpyrrole was systematically observed in organic solutions. The polymer, which has a unique molecular structure, exhibited good photoluminescence in organic solutions. The emission peak of the polymer exhibited one strong green emission band at around 510nm in common organic solutions. The maximum fluorescence quantum yield of the polymer was found to be 0.16 in NMP solution with fluorescein as standard. At the same concentration, the photoluminescence intensity increased in the order of CHCl3, THF, DMSO, CH2Cl2 and NMP. The photoluminescence spectrum had a slight red shift as the polarity of the solvents increased. The photoluminescence intensity also increased with the polarity of the solvent, except DMSO. This is because of its hygroscopicity in air and its viscosity. In THF solutions, the photoluminescence intensity increased until the concentration reached a certain weight percent (3.0×10−2 wt.%) and then decreased with higher concentrations. This was most likely due to quenching in the aggregate phase. Furthermore, iron ion was a quencher in the DMSO solution. In a mixed solvent system of DMSO and water, water showed a typical quenching effect. [Copyright &y& Elsevier]

This report details the synthesis and characterization of a new diformyl pyrrole derivative 2 and its macrocyclic derivative 3. The new compounds were characterized by FT-IR, 13C NMR, and ¹H NMR spectroscopies and via mass spectrometric analysis. The structure of 2 in the solid state was determined using X-ray diffraction methods (monoclinic, P21/c, a = 17.3760(7), b = 4.9719(2), c = 15.5374(5) Å β = 105.892(2) °, V = 1291.00(9) ų, and Z = 4). The molecular structure is stabilized by N-H…O and C-H…O intermolecular hydrogen bonds. The present bisformylpyrrole derivative 2 provides a new precursor that may be useful in the synthesis of new, functional macrocyclic systems. [ABSTRACT FROM AUTHOR]

The new dibranched, heterocyclic "push-pull" chromophores bis{ 1 -(pyridin-4-yl)-2-[2-(N-methyl- pyrrol-5-yl)]ethane}methane (1), 1 -(pyrid-4-yl)-2-(N-methyl-5-formylpyrrol-2-yl)ethylene (2), { 1 -(N-methyl- pyridinium-4-yl)-2-[2-(N-methylpyrrol-5-yl)]ethane}{(1 -(pyridin-4-yl)-2-[2-(N-methylpyrrol-5-yl)lethane}- methane (3), N-methyl-2-[1 -(N-methylpyrid-4-yl)ethen-2-yl]-5-[pyrid-4-yl]ethen-2-yl]pyrrole iodide (4), bis- {1-(N-methyl-4-pyridinio)-2-[2-(N-methylpyrrol-5-yl)]ethane}methane iodide (5), and N-methyl-2,5-[1-(N- methylpyrid-4-yl)ethen-2-yl]pyrrole iodide (6) have been synthesized and characterized. The neutral (1 and 2) and monomethyl salts (3 and 4) undergo chemisorptive reaction with iodobenzyl-functionalized surfaces to afford chromophore monolayers SA-1/SA-2 and SA-3/SA-4, respectively. Molecular structures and other physicochemical properties have been defined by 1H NMR, optical spectroscopy, and XRD. Thin-film characterization by a variety of techniques (optical spectroscopy, specular X-ray reflectivity, atomic force microscopy, X-ray photoelectron spectroscopy, and angle-dependent polarized second harmonic generation) underscore the importance of the chromophore molecular architecture as well as film growth method on film microstructure and optical/electrooptic response. [ABSTRACT FROM AUTHOR]

The SERS spectra of the aligned polypyrrole tubules were studied carefully. The oriented structure of the polymer chains was cautiously discussed and the conclusion was reached that the pyrrole ring lied parallel to the alumina template tubule wall and the orientation of the polymer chains was parallel to the axle of the tubules. The relationship between the structure and the unique properties was also well explained. [Copyright &y& Elsevier]

N-confused and N-fused porphyrins revealed quite unique photophysical properties arising from their perturbed π-conjugation pathways induced by structural modifications such as confusion and fusion of pyrrole rings compared with their parent porphyrin molecules. [ABSTRACT FROM AUTHOR]