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A novel heteroleptic ruthenium complex carrying a heteroaromatic-4,4'-pi-conjugated 2,2'-bipyridine [Ru(II)LL'(NCS)(2)] (L = 4,4'-bis[(E)-2-(3,4-ethylenedioxythien-2-yl)vinyl]-2,2'-bipyridine, L' = 4,4'-(dicarboxylic acid)-2,2'-bipyridine) was synthesized and used in dye-sensitized solar cells, yielding photovoltaic efficiencies of 9.1% under standard global AM 1.5 sunlight.

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The first example of a heteroarylvinylene π-conjugated quaterpyridine Ru(II) sensitizer (N1044) was synthesized and used in dye-sensitized solar cells; the dye has an effective panchromatic absorption band, covering the entire visible spectrum up to the NIR region, and superior electrochemical characteristics (HOMO/LUMO and bandgap energies) with respect to previous representative Ru(II) bi- and quaterpyridine sensitizers. A record IPCE curve ranging from 360 to 920 nm has been measured with a maximum of 65% at 646 nm and still 33% efficiency at 800 nm; this leads to substantially increased photocurrent (19.2 mA cm(-2)) when compared to the prototype N719 Ru(II) sensitizer.

We report on the optical properties of polystyrene opals infiltrated with solutions of ad hoc synthesized heteroaromatic quadrupolar dyes endowed with strong nonlinear optical properties (two-photon absorption). Transmittance spectroscopy of opals infiltrated with dye water solutions shows both a bathochromic shift and a reduced width of the photonic crystal stop band. Moreover, variable angle transmittance spectra highlight the high energy dispersion of the stop band upon increasing the incidence angle. Photoluminescence spectra recorded at different emission angles with respect to the normal of the sample for such infiltrated opals show that the emission spectrum is strongly modified at the stop band according to the opal dispersion properties. A careful comparison of the intensity and spectral properties of photoluminescence in opals possessing a properly tuned photonic stop band is reported and discussed. Two different effects are observed: when concentrated solutions are used, emitted light filtering due to the photonic stop band is observed. On the other hand, by properly reducing solution self-absorption, directional enhancement of emission in the high energy side of the stop band is observed. Physical mechanisms responsible for this phenomenon are discussed.

Innovative mimics of lipid A were synthesized and shown to efficiently inhibit lipid A induced cytokine production in human dendritic cells and macrophages. These compounds, which consist of a D‐glucose unit functionalized with an amine, ammonium, or hydroxylamine group and a five‐membered ring at C6 (see structures) are promising leads for antisepsis‐drug development owing to their lack of toxicity and their selectivity for the TLR4 receptor.

Conotoxins are small, disulfide-rich peptides that have been isolated from Conus, a large genus of predatory marine snails. The primary structures of more than 100 conotoxins have been determined and classified into gene superfamilies on the basis of the amino acid sequences of the signal peptides of their a-Conotoxins from marine snails are known to be selective and potent competitive antagonists of nicotinic acetylcholine receptors. Here we describe the purification, structural features and activity of two novel toxins, SrIA and SrIB, isolated from Conus spurius collected in the Yucatan Channel, Mexico. As determined by direct amino acid and cDNA nucleotide sequencing, the toxins are peptides containing 18 amino acid residues with the typical 4 ⁄ 7-type framework but with completely novel sequences. Therefore, their actions (and that of a synthetic analog, [c15E]SrIB) were compared to those exerted by the a4 ⁄ 7-conotoxin EI from Conus ermineus, used as a control. Their target specificity was evaluated by the patch-clamp technique in mammalian cells expressing a 1 b 1 cd, a 4 b 2 and a 3 b 4 nicotinic acetylcholine receptors. At high concentrations (10 lm), the peptides SrIA, SrIB and [c15E]SrIB showed weak blocking effects only on a 4 b 2 and a 1 b 1 cd subtypes, but EI also strongly blocked a 3 b 4 receptors. In contrast to this blocking effect, the new peptides and EI showed a remarkable potentiation of a 1 b 1 cd and a 4 b 2 nicotinic acetylcholine receptors if briefly (2-15 s) applied at concentrations several orders of magnitude lower (EC 50 , 1.78 and 0.37 nm, respectively). These results suggest not only that the novel a-conotoxins and EI can operate as nicotinic acetylcholine receptor inhibitors, but also that they bind both a 1 b 1 cd and a 4 b 2 nicotinic acetylcholine receptors with very high affinity and increase their intrinsic cholinergic response. Their unique properties make them excellent tools for studying the toxin-receptor interaction, as well as models with which to design highly specific therapeutic drugs.Abbreviations a 1 b 1 cd, muscular nicotinic acetylcholine receptor; a 3 b 4 , peripheral nervous system nicotinic acetylcholine receptor; a 4 b 2 , central nervous system nicotinic acetylcholine receptor; Acm, S-acetamidomethyl; ACN, acetonitrile; [c15E]SrIB, synthetic a-conotoxin from Conus spurius; nAChR, nicotinic acetylcholine receptor; PTH, phenylthiohydantoin; SrIA, a-conotoxin IA from Conus spurius; SrIB, a-conotoxin IB from Conus spurius.

Two dimers of a heteroaromatic quadrupolar (acceptor-donor-acceptor) chromophore have been synthesized with different interchromophoric distances. Optical spectra of dimers in solution show a red shift of the linear absorption band upon decreasing the interchromophore distance, while fluorescence and two-photon absorption spectra are only marginally affected by the interactions. A bottom up approach is adopted to describe the spectra: via a detailed spectroscopic analysis of the monomeric species in solution, we define an essential-state model for the isolated chromophore and use this information to set up a model for the dimers also accounting for interchromophore electrostatic interactions. To discriminate between static screening governed by the static dielectric constant and dynamical screening at optical frequencies, we first solve the problem in the mean-field approximation and then define the excitonic Hamiltonian on the resulting best excitonic basis. Along this line, the evolution of spectral properties with the interchromophore distance is properly rationalized.