The photosynthetic reaction center (RC) from the purple Rhodobacter (R.) sphaeroides bacterium is a protein with unique photoconversion capability that can be exploited in hybrid systems for energy conversion. We have developed a tailored aryleneethynylene organic fluorophore (AE750) acting as efficient light harvesting antenna and successfully bioconjugated it to the photosynthetic RC. We have also demonstrated that, under suitable conditions, the biohybrid AE750-RC system can outperform the energy photoconversion ability of the native protein.

An alkoxy-substituted poly(phenylene thiophene) is used in order to suspend single-walled carbon nanotubes in an organic solvent. The suspension is spread on the air water interface of a Langmuir trough and the floating film is characterized by means of Brewster angle microscopy and UV-visible reflection spectroscopy and the compression isotherm is recorded. The polymer/carbon-nanotube blend is transferred onto different substrates using the Langmuir-Blodgett technique. AFM measurements indicate the formation of globular structures for the samples transferred at low surface-pressure values and a tubular morphology for high-pressure-deposited samples. AFM analysis is repeated on a sample exposed to soft X-rays for about 5 h and a highly organized structure of bundles of carbon nanotubes rises up. Samples with different numbers of layers are transferred onto ITO substrates by means of the Langmuir-Blodgett method and are tested as photocathodes in a photo-electrochemical cell. A V(oc) of 0.18 V, an I(sc) of 85.8 mA, FF of 40.0%, and eta of (6.23 x 10(-3))% are obtained.

Humankind is in great need of new energy sources. The use of solar radiation for powering the planet would fulfil the energy requirements of Earth's inhabitants as well as greatly mitigate tension flares arising from the uneven distribution of fossil fuels and environmental problems associated to their extraction procedures. How to proceed than? Easy to say! Mother Nature is inspiring: all life on earth is based on the conversion of the solar radiation into high energy molecules, including gas and oil human beings are consuming these days, by mean of the so-called primary photoconverters, i.e. the photosynthetic organisms, plants, algae and some kind of bacteria. So, let's learn from Nature and assemble in our laboratories artificial systems capable of exploiting solar energy for photocatalysis and electrical energy production, i.e. mimic photosynthesis. Not an easy task of course, but a large number of laboratory are heavily involved since the last 25 years in the field of artificial photosynthesis and are obtaining encouraging results. The photosynthetic apparatus used by photosynthetic organisms to convert solar energy and drive their metabolism is the photochemical core where photoconversion takes place, and is constituted by a protein portion allocating several pigments directly involved in the harvesting of solar light and in the subsequent sequence of electron transfer reactions which eventually lead to the formation of an electron-hole couple to be used for any energy requiring process. In artificial photosynthesis the role of the protein scaffold in often ignored and attention is devoted to assembly molecular system for optimising light harvest and electron-transfer reactions, focussing to the "less-complex" portion of the photosynthetic apparatus. What would be a different paradigm in artificial photosynthesis? Assemble artificial photoconverters using genuine natural components formed by hybrid organic-biologic systems. The hybrids have a central protein, the so-called photosynthetic reaction center (RC) that converts sunlight into a charge-separated state having a lifetime sufficient to allow ancillary chemistry to take place. The RCs can be eventually garnished with opportune organic moieties to be used for different applications.The state of the art of these hybrid organic-biologic photosynthetic assemblies will be reviewed.

The reconstitution of the integral membrane protein photosynthetic reaction center (RC) in polymersomes, i.e. artificial closed vesicles, was achieved by the micelle-to-vesicle transition technique, a very mild protocol based on size exclusion chromatography often used to drive the incorporation of proteins contemporarily to liposome formation. An optimized protocol was used to successfully reconstitute the protein in a fully active state in polymersomes formed by the tri-block copolymers PMOXA<inf>22</inf>-PDMS<inf>61</inf>-PMOXA<inf>22</inf>. The RC is very sensitive to its solubilizing environment and was used to probe the positioning of the protein in the vesicles. According to charge-recombination experiments and to the enzymatic activity assay, the RC is found to accommodate in the PMOXA<inf>22</inf> region of the polymersome, facing the water bulk solution, rather than in the PDMS<inf>61</inf> transmembrane-like region. Furthermore, polymersomes were found to preserve protein integrity efficiently as the biomimetic lipid bilayers but show a much longer temporal stability than lipid based vesicles.

The covalent functionalization of photosynthetic proteins with properly tailored organic molecular antennas represents a powerful approach to build a new generation of hybrid systems capable of exploiting solar energy. In this paper the strategy for the synthesis of the tailored aryleneethynylene organic fluorophore (AE) properly designed to act as light harvesting antenna is presented along with its successful bioconjugation to the photosynthetic reaction center RC from the bacterium Rhodobacter sphaeroides

The aggregation behavior of two D-glucose-substituted phenyleneethynylenes, an alternate copolymer (AP) and a homooligomer (HO), has been investigated by means of UV-vis absorption, circular dichroism (CD) and fluorescence spectroscopy. CD reveals superior capability to detect the early stages of aggregation and to provide information about aggregate geometries. The multiband CD spectrum of the AP and of analogous chiral PPEs is rationalized on the basis of the exciton coupling between vibronic transitions localized on proximate portions of the chromophoric chains.

A high-throughput crystallographic investigation on several crystals of photosynthetic reaction center covalently bound to an ad-hoc synthesized artificial antenna (AE600) is presented. The investigation did not show a preferential binding site of the antenna molecule AE600 to the reaction center in the solid phase. An accurate crystallographic study allowed identifying a lysine residue sitting on periplasmic side of the protein as one of the bioconjugation sites. The residue sits on subunit M of the protein, in close proximity to the bacteriochlorophylls of the reaction center involved in the light absorption and conversion processes. Distances obtained from the crystallographic structure confirm that energy transfer between the antenna and the protein proceed with the Förster resonance mechanism.

the paper is a communication there is no abstract.

The synthetic conjugated poly(1, 4-arylene-2, 5-thienylene) containing benzo[c][2,1,3]thiadiazolemonomeric units (Bz-PAT) is proposed as active layer for the selective detection of mercuric ions. TheBz-PAT polymer chemical structure induces the formation of a disordered film with numerous vacanciesand the size of these defects could be exploited for a reversible trapping of mercuric ions. For thesereasons the Langmuir-Schaefer (LS) deposition method has been employed for transferring Bz-PATlayers with the desired accurate bi-dimensional organization control of the layer and with a high controlof the deposition parameters. In this contribution, the frequency variation of a quartz crystal microbalancewith 10, 20, 30 and 40 LS runs of Bz-PAT has been investigated in response to the injection of aqueoussolutions of HgCl2, Pb(NO3)2, NiCl2, CdCl2 and ZnSO4 at different concentrations (0.5 mM, 1 mM, 5mM). An almost linear dependence on the number of the LS layers and hence on the film thickness,measured by means of ellipsometric spectroscopy, has been found in terms of sensor response toconcentration of Hg2+ ions fluxed. By means of UV-Vis spectroscopy, the variations in the ?-?*absorption band of the polymer, attributed to the thiophene segment, induced by HgCl2 injection has beenanalyzed and explained as a consequence of the electron transfer from the mercuric ion to the polymersolid film. These results, together with the linear relation found between the number of deposited layersand LS film thickness, suggest that the sensing mechanism can be explained both by an electroninteraction active layer and analyte and a diffusion mechanism of Hg2+ into the solid film that reaches anasymptotic value at 30 runs (about 80 nm), then a higher number of layers does not influence the sensorsensibility.

Four linear terarylene molecules (i) 4-nitro-terphenyl-4?-methanethiol (NTM), (ii) 4-nitro-terphenyl-3?,5?-dimethanethiol (NTD), (iii) ([1,1?;4?,1?] terphenyl-3,5-diyl)methanethiol (TM), and (iv) ([1,1?;4?,1?] terphenyl-3,5-diyl)dimethanethiol (TD) have been synthesized and their self-assembled monolayers (SAMs) have been obtained on polycrystalline gold. NTM and NTD SAMs have been characterized by X-ray photoelectron spectroscopy, Kelvin probe measurements, electrochemistry, and contact angle measurements. The terminal nitro group (-NO2) is irreversibly reduced to hydroxylamine (-NHOH), which can be reversibly turned into nitroso group (-NO). The direct comparison between NTM/NTD and TM/TD SAMs unambiguously shows the crucial influence of the nitro group on electrowetting properties of polycrystalline Au. The higher grade of surface tension related to NHOH has been successfully exploited for basic operations of digital ?-fluidics, such as droplets motion and merging.

Light machine: The simplest photosynthetic protein able to convert sunlight into other energy forms is covalently functionalized with a tailored organic dye to obtain a fully functional hybrid complex that outperforms the natural system in light harvesting and conversion ability

The bioconjugation of photosynthetic proteins with efficient organic light harvesting antennas is a very intriguing approach to build novel hybrid organic-biological machineries that, mimicking nature, employ solar energy to generate photocurrents or to drive thermodynamically unfavoured reactions, reaching efficiencies higher than those obtainable by their natural conterparts. Such hybrid systems are potentially useful as active materials in new generation devices for photovoltaics and biosensing. In the frame of our studies on organic-biological hybrids for solar energy conversion,[1] here we present the design, synthesis and preliminary characterization of a series of heptamethine cyanine dyes (such as Cian-1 in Figure 1a) particularly suitable as light harvesting antennas for the photosynthetic Reaction Center (RC) of the purple bacterium Rhodobacter sphaeroides strain R26. These molecules have been properly tailored to have efficient light absorption in the visible spectral range, where the RC absorbance is very low, and efficient emission in the near infrared region, in correspondence of the highest RC absorption peaks.Moreover, the charged sites within their molecular structure make these molecules highly soluble in detergent aqueous environment where the RC is stable, this allowing them to approach the bioconjugation sites of the protein. Finally, the synthesized cyanines are endowed with a carboxylic moiety useful for their covalent binding to the amino groups of the RC lysine residues. Our preliminary results show that the bioconjugation of these organic antennas to the RC is expected to be a very profitable strategy to afford highly efficient organic-biological hybrids for solar energy conversion.

Photosynthesis is responsible for the photochemical conversion of light into the chemical energy that fuels the planet Earth. The photochemical core of this process in all photosynthetic organisms is a transmembrane protein called the reaction center. In purple photosynthetic bacteria a simple version of this photoenzyme catalyzes the reduction of a quinone molecule, accompanied by the uptake of two protons from the cytoplasm. This results in the establishment of a proton concentration gradient across the lipid membrane, which can be ultimately harnessed to synthesize ATP. Herein we show that synthetic protocells, based on giant lipid vesicles embedding an oriented population of reaction centers, are capable of generating a photoinduced proton gradient across the membrane. Under continuous illumination, the protocells generate a gradient of 0.061 pH units per min, equivalent to a proton motive force of 3.6 mV.min(-1). Remarkably, the facile reconstitution of the photosynthetic reaction center in the artificial lipid membrane, obtained by the droplet transfer method, paves the way for the construction of novel and more functional protocells for synthetic biology.

Single-walled carbon nanotubes (SWCNTs)were suspended in 1,2-dichloroethane by noncovalentfunctionalization with a low-band-gap conjugated polymer 1alternating dialkoxyphenylene-bisthiophene units with benzo-[c][2,1,3]thiadiazole monomeric units. The suspended 1/SWCNT blend was transferred onto different solid substratesby the Langmuir-Schaefer deposition method, resulting infilms with a high percentage of aligned nanotubes. Photoelectrochemical characterization of 1/SWCNT thin films on indium-tinoxide showed the benefits of SWCNT alignment for photoconversion efficiency.

We describe the synthesis of two novel poly(1,4-arylene-2,5-thienylene)s P1 and P2 containing benzo[c][2,1,3]thiadiazole monomeric units via Suzuki-Miyaura polymerization of a thiophene diboronic ester with aryl diiodides. The use of a catalyst complex consisting of Pd(OAc)(2) in combination with the electron-rich biaryl phosphine S-Phos resulted in efficient polymerization reactions. The polymers synthesized, P1 and P2, were characterized by UV-vis spectroscopy and cyclic voltammetry. Theoretical calculations and electrochemical measurements on P1 suggested a favorable position of the molecular orbitals for employment in polymer solar cells in combination with PCBM. Devices containing P1:PCBM 1:2 in the active layer showed an efficiency of 1.2% by simple spin casting from chloroform. (C) 2011 Elsevier B.V. All rights reserved.

A new set of linear oligoarylene thiol molecules, namely (40-(Thiophen-2-yl)Biphenyl-3,5-diyl)Dimethanethiol (TBD), (40-(Thiophen-2-yl)Biphenyl-4-yl)Methanethiol (TBM) and ([1,10;40,100]Terphenyl-3,5-diyl)Dimethanethiol (TD), were synthesized and used for functionalizing thepolycrystalline gold electrodes. Such molecules differ for the number of anchoring groups (TBM vs.TBD) and the terminal rings (TD vs. TBD). As shown by electrochemical measurements, they formhomogeneous and pinholes-free self-assembly monolayers (SAMs) when deposited on the goldelectrode. Moreover, the wettability of the functionalized surface and the morphological changes ofpentacene films grown on SAMs were investigated by contact angle and atomic force microscopy,respectively. OTFT has been used as organic gauge for investigating the metal-SAM-organicsemiconductor structure. Charge carriers mobility, threshold voltage, contact resistance were measuredin both air and vacuum to assess the influence of the anchoring groups and the terminal rings to thetransistor performance. Although these SAMs do not show an improvement of mobility due to anincrease of contact resistance, they allow a better modulation of the current flowing across theelectrode-organic semiconductor (OS) interface, pointing out the structural differences between thethree SAMs in terms of resistance drop combined with the critical voltage.

Photosynthetic Reaction Center (RC) is a transmembrane photoenzyme capable of converting absorbed photons into electron-hole pairs with almost unitary efficiency. The unique properties of this natural photoconverter attract considerable interest for its use as functional component in nanomaterials and bioelectronics devices. Implementation of RC into nanostructures or anchoring on devices' electrode surfaces require the development of suitable chemical manipulation. Here we report our methods to embed this protein in soft nanostructures or to covalently attach it on surfaces without denaturating it or altering its chemical properties. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Four thiolated oligoarylene molecules (i) 4-methoxy-terphenyl-4 ''-methanethiol (MTM), (ii) 4-methoxy-terphenyl-3 '',5 ''-dimethanethiol (MTD), (iii) 4-nitro-terphenyl-4 ''-methanethiol (NTM), and (iv) 4-nitro-terphenyl-3 '',5 ''-dimethanethiol (NTD) were synthesized and self-assembled as monolayers (SAMs) on polycrystalline Au electrodes of organic field-effect transistors (OFETs). SAMs were characterized by contact angle and AC/DC electrochemical measurements, whereas atomic force microscopy was used for imaging the pentacene films grown on the coated electrodes. The electrical properties of functionalized OFETs, the electrochemical SAMs features and the morphology of pentacene films were correlated to the molecular organization of the thiolated oligoarylenes on Au, as calculated by means of the density functional theory. This multi-methodological approach allows us to associate the systematic replacement of the SAM anchoring head group (viz. methanethiol and dimethanethiol) and/or terminal tail group (viz. nitro-, -NO2, and methoxy, -OCH3) with the change of the electrical features. The dimethanethiol head group endows SAMs with higher resistive features along with higher surface tensions compared with methanethiol. Furthermore, the different number of thiolated heads affects the kinetics of Au passivation as well as the pentacene morphology. On the other hand, the nitro group confers further distinctive properties, such as the positive shift of both threshold and critical voltages of OFETs with respect to the methoxy one. The latter experimental evidence arise from its electron-withdrawing capability, which has been verified by both DFT calculations and DC electrochemical measurements

Nanostructured biosilica extracted from diatoms are extensively exploited in a wide number of applications including photonics, biosensing, and drug delivery.[1] Very recently diatoms biosilica has been investigated as smart multifunctional biomaterial for cell growth.[2] Based on these results, we focused on the in vivo engineering of diatoms frustules with sodium alendronate, an osteoclasts inhibitor and a bone cells proliferation enhancer. The obtained doped frustules could be developed as multifunctional scaffolds able to promote osteoblast cells adhesion and proliferation (Fig. 1). in vivo doped with sodium alendronate (NaAl ).

Phenylene-thiophene oligomers bearing peracetylated beta-D-glucose or N-BOC-L-phenylalanine as chiral substituents were synthesized in good yields by a versatile protocol based on the Suzuki-Miyaura cross-coupling reaction. Aryl iodides bearing the chiral biomolecules as substituents efficiently reacted with pinacol boronates of bi- or terthiophenes leading to the bio-functionalized oligomers in good yields. (C) 2010 Elsevier Ltd. All rights reserved.

Organic polymeric and molecular semiconductorsfunctionalized with biological molecules represent a veryinteresting class of materials for highly selective electrical andoptical sensors. Molecular design and synthetic approaches toseveral bio-substituted conjugated oligomers and polymers arediscussed, highlighting the impact of synthetic pathways on theproperties of the materials.

A novel class of tetrathiolated aryleneethynylene oligomers was obtained by the Cassar-Heck-Sonogashira coupling between S,S'-(5-ethynyl-1,3-phenylene) bis(methylene) diethanethioate (1) and aryl diiodides or dibromides. Although standard coupling conditions are effective in the case of iodo derivatives, the addition of free triphenylphosphane to the reaction mixture was required to overcome the slower reaction rate of dibromoarenes. Oligomers with an extended conjugated system could be obtained starting from a higher homologue of 1 by applying the same synthetic approach. These oligomers represent interesting molecular wires, potentially able to self-assemble on various substrates, including gold and other noble metals in the form of thin films or nanoparticles. The chelating arrangement of the thiol functionalities should ensure stable anchoring and would also represent an interesting novel feature in the study of single molecule conduction with respect to traditional monodentate systems.

Functionalization with fluorine atoms represents a versatile structural modification tofinely tune both the emission colour and the electronic properties of organic and organometallicelectroluminescent compounds. This paper reports an overview of our systematic investigation onthe design and synthesis of the fluorinated version of two important classes of materials for organiclight emitting diodes (OLEDs), namely poly(arylenevinylene)s and phosphorescent phenylpyridineIridium complexes. Synthetic pathways based on organometallic methodologies affordingselectively fluorinated molecular structures will be discussed together with a summary of the effectof fluorination on the optical properties of the resulting materials. In particular we will highlight thepossibilities offered by the organometallic methodologies as straightforward and resourceful toolsto provide a wide series of fluorinated molecular architectures with high regio- andstereoselectivity, mild experimental conditions and good yields.

The photosynthetic reaction center (RC) from the Rhodobacter sphaeroides bacterium has been covalently bioconjugated with a NIR-emitting fluorophore (AE800) whose synthesis was specifically tailored to act as artificial antenna harvesting light in the entire visible region. AE800 has a broad absorption spectrum with peaks centered in the absorption gaps of the RC and its emission overlaps the most intense RC absorption bands, ensuring a consistent increase of the protein optical cross section. The covalent hybrid AE800-RC is stable and fully functional. The energy collected by the artificial antenna is transferred to the protein via FRET mechanism, and the hybrid system outperforms by a noteworthy 30% the overall photochemical activity of the native protein under the entire range of visible light. This improvement in the optical characteristic of the photoenzyme demonstrates the effectiveness of the bioconjugation approach as a suitable route to new biohybrid materials for energy conversion, photocatalysis, and biosensing. © 2016 American Chemical Society.

Self-assembled monolayers (SAMs) derived of 4-methoxy-terphenyl-300,500-dimethanethiol (TPDMT) and 4-methoxyterphenyl-400-methanethiol (TPMT) have been prepared by chemisorption from solution onto gold thin films andnanoparticles. The SAMs have been characterized by spectroscopic ellipsometry, Raman spectroscopy and atomic forcemicroscopy to determine their optical properties, namely the refractive index and extinction coefficient, in an extendedspectral range of 0.75-6.5 eV. From the analysis of the optical data, information on SAMs structural organization hasbeen inferred. Comparison of SAMs generated from the above aromatic thiols to well-known SAMs generated from thealkanethiol dodecanethiol revealed that the former aromatic SAMs are densely packed and highly vertically oriented,with a slightly higher packing density and a absence of molecular inclination in TPMT/Au. The thermal behaviorof SAMs has also been monitored using ellipsometry in the temperature range 25-500
C. Gold nanoparticlesfunctionalized by the same aromatic thiols have also been discussed for surface enhanced Raman spectroscopyapplications. This study represents a step forward tailoring the optical and thermal behavior of surfaces as well asnanoparticles.

La presente invenzione riguarda dispositivi sensori analiti gassosi comprendenti transistor a film sottile organico e, in particolare, sensori in grado di effettuare la discriminazione enantiomerica di analiti gassosi. I film sottili organici sono caratterizzati dal fatto di comprendere un composto di formula (I).