Pseudomorphic Transformation in Nanostructured Thiophene-Based Materials.

This study reveals the capability of nanostructured organic materials to undergo pseudomorphic transformations, a ubiquitous phenomenon occurring in the mineral kingdom that involves the replacement of a mineral phase with a new one while retaining the original shape and volume. Specifically, it is demonstrated that the postoxidation process induced by HOF·CHCN on preformed thiophene-based 1D nanostructures preserves their macro/microscopic morphology while remarkably altering their electro-optical properties by forming a new oxygenated phase. Experimental evidence proves that this transformation proceeds via an interface-coupled dissolution-precipitation mechanism, leading to the growth of a porous oxidized shell that varies in thickness with exposure time, enveloping the pristine smooth core.

Multifunctional Photoelectroactive Materials for Optoelectronic Applications Based on Thieno[3,4-b]pyrazines and Thieno[1,2,5]thiadiazoles.

In this study, we introduce a novel family of symmetrical thiophene-based small molecules with a Donor-Acceptor-Donor structure. These compounds feature three different acceptor units: benzo[c][1,2,5]thiadiazole (Bz), thieno[3,4-b]pyrazine (Pz), and thieno[1,2,5]thiadiazole (Tz), coupled with electron donor units based on a carbazole-thiophene derivative. Using Density Functional Theory (DFT), we investigate how the molecular geometry and strength of the central acceptor unit impact the redox and spectroscopic properties.

Ionic Push-Pull Polythiophenes: A Further Step towards Eco-Friendly BHJ Organic Solar Cells.

Four new conjugated polymers alternating benzothiadiazole units and thiophene moieties functionalized with ionic phosphonium or sulfonic acid salts in the side chains were synthesized by a postfunctionalization approach of polymeric precursors. The introduction of ionic groups makes the conjugated polymers soluble in water and/or polar solvents, allowing for the fabrication of bulk heterojunction (BHJ) solar cells using environmentally friendly conditions. All polymers were fully characterized by spectroscopic, thermal, electrochemical, X-ray diffraction, scanning electron, and atomic force techniques.

Spontaneous Coassembly of the Protein Terthiophene into Fluorescent Electroactive Microfibers in 2D and 3D Cell Cultures.

Protein-based microfibers are biomaterials of paramount importance in materials science, nanotechnology, and medicine. Here we describe the spontaneous in situ formation and secretion of nanostructured protein microfibers in 2D and 3D cell cultures of 3T3 fibroblasts and B104 neuroblastoma cells upon treatment with a micromolar solution of either unmodified terthiophene or terthiophene modified by mono-oxygenation (thiophene → thiophene -oxide) or dioxygenation (thiophene → thiophene ,-dioxide) of the inner ring. We demonstrate via metabolic cytotoxicity tests that modification to the -oxide leads to a severe drop in cell viability.

Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular Consensus on genetically modified cells. VI: Accreditation process.

The adherence to accreditation programs proves the institutions' voluntary effort to pursue the quality and safety of their products and services by meeting internationally accepted standards audited by experts in the field, external to the service. Meeting such standards often exceeds domestic legal requirements. However, service providers are not released from complying with the legal requirements, both local and international, pertinent to the field.

Human Serum Albumin-Oligothiophene Bioconjugate: A Phototheranostic Platform for Localized Killing of Cancer Cells by Precise Light Activation.

The electronic, optical, and redox properties of thiophene-based materials have made them pivotal in nanoscience and nanotechnology. However, the exploitation of oligothiophenes in photodynamic therapy is hindered by their intrinsic hydrophobicity that lowers their biocompatibility and availability in water environments. Here, we developed human serum albumin (HSA)-oligothiophene bioconjugates that afford the use of insoluble oligothiophenes in physiological environments.

Nanostructuring Iridium Complexes into Crystalline Phosphorescent Nanoparticles: Structural Characterization, Photophysics, and Biological Applications.

One of the key challenges in materials science is to control the properties of a material by directing its supramolecular arrangement. Here we show that iridium complexes, such as FIrpic, Ir-PPY, and Ir-MDQ, can be organized into crystalline and phosphorescent nanoparticles through the nanoprecipitation method, which allows thorough modification of their functional properties. Moreover, we found that it is possible to combine different iridium complexes into a single multicomponent nanostructure, thus creating nanoparticles whose photonic properties derive from the close spatial proximity of the electronic excited states of the different Ir complexes.

Thermodynamically versus Kinetically Controlled Self-Assembly of a Naphthalenediimide-Thiophene Derivative: From Crystalline, Fluorescent, n-Type Semiconducting 1D Needles to Nanofibers.

The control over aggregation pathways is a key requirement for present and future technologies, as it can provide access to a variety of sophisticated structures with unique functional properties. In this work, we demonstrate an unprecedented control over the supramolecular self-assembly of a semiconductive material, based on a naphthalenediimide core functionalized with phenyl-thiophene moieties at the imide termini, by trapping the molecules into different arrangements depending on the crystallization conditions. The control of the solvent evaporation rate enables the growth of highly elaborated hierarchical self-assembled structures: either in an energy-minimum thermodynamic state when the solvent is slowly evaporated forming needle-shaped crystals (polymorph α) or in a local energy-minimum state when the solvent is rapidly evaporated leading to the formation of nanofibers (polymorph β).

Titania nano-coated quartz wool for the photocatalytic mineralisation of emerging organic contaminants.

Many emerging contaminants pass through conventional wastewater treatment plants, contaminating surface and drinking water. The implementation of advanced oxidation processes in existing plants for emerging contaminant remediation is one of the challenges for the enhancement of water quality in the industrialised countries. This paper reports on the production of a TiO nano-layer on quartz wool in a relevant amount, its characterisation by X-ray diffraction and scanning electron microscopy, and its use as a photocatalyst under ultraviolet radiation for the simultaneous mineralisation of five emerging organic contaminants (benzophenone-3, benzophenone-4, carbamazepine, diclofenac, and triton X-100) dissolved in deionised water and tap water.

Poly(3-hexylthiophene) Nanoparticles Containing Thiophene-S,S-dioxide: Tuning of Dimensions, Optical and Redox Properties, and Charge Separation under Illumination.

We describe the preparation of poly(3-hexylthiophene-S,S-dioxide) nanoparticles using Rozen's reagent, HOF·CHCN, either on poly(3-hexylthiophene) (P3HT) or on preformed P3HT nanoparticles (P3HT-NPs). In the latter case, core-shell nanoparticles (P3HT@PTDO-NPs) are formed, as confirmed by X-ray photoelectron spectroscopy measurements, indicating the presence of oxygen on the outer shell. The different preparation modalities lead to a fine-tuning of the chemical-physical properties of the nanoparticles.

Versatile bisethynyl[60]fulleropyrrolidine scaffolds for mimicking artificial light-harvesting photoreaction centers.

Fullerene-based tetrads, triads, and dyads are presented in which [60]fulleropyrrolidine synthons are linked to an oligo(p-phenyleneethynylene) antenna at the nitrogen atom and to electron-donor phenothiazine (PTZ) and/or ferrocene (Fc) moieties at the α carbon of the pyrrolidine cycle through an acetylene spacer. Cyclic voltammetry and UV/ Vis absorption spectra evidence negligible ground-state electronic interactions among the subunits. By contrast, strong excited-state interactions are detected upon selective light irradiation of the antenna (UV) or of the fullerene scaffold (Vis).

Synergic Exfoliation of Graphene with Organic Molecules and Inorganic Ions for the Electrochemical Production of Flexible Electrodes.

A facile and efficient method based on electrochemistry for the production of graphene-based materials for electronics is demonstrated. Uncharged acetonitrile molecules are intercalated in graphite by electrochemical treatment, owing to the synergic action of perchlorate ions dissolved in acetonitrile. Then, acetonitrile molecules are decomposed with microwave irradiation, which causes gas production and rapid graphite exfoliation, with an increase in the graphite volume of up to 600 %.

Photoinduced processes in a dyad made of a linear and an angular perylene bisimide.

A dyad (PI0-PIa) made of a linear (PI0) and an angular (PIa) perylene biscarboximide is synthesized and its spectroscopic, electrochemical and photophysical properties investigated in solvents of various polarity. PIa is characterized by a high intersystem crossing. The spectroscopy and electrochemistry data point to a modest electronic coupling.

π-Core tailoring for new high performance thieno(bis)imide based n-type molecular semiconductors.

The synthesis and characterization of two thieno(bis)imide based n-type semiconductors with electron mobilities of up to 0.3 cm(2) V(-1) s(-1) are described. The relationships between the electronic features of the π-inner core and the functional properties of the new materials are also discussed.

Self-assembly and electrical properties of a novel heptameric thiophene-benzothiadiazole based architectures.

A novel semiconducting benzothiadiazole (BTZ)-thiophene (T) co-oligomer having an unprecedented BTZ-T alternated motif has been synthesized and self-assembled into micrometer sized fibers by simple solution processing. The electrical properties of these low-dimensional architectures have been characterized by integrating them in an organic field-effect transistor.

Photophysical and redox properties of perylene bis- and tris-dicarboximide fluorophores with triplet state formation: transient absorption and singlet oxygen sensitization.

A detailed photophysical characterization of a couple of new perylene imide derivatives, a carboxylic trisimide PIx, and an asymmetrically substituted carboxylic bisimide PIa is presented. PIx and PIa have the lowest singlet excited state just below 2.6 eV.

Thienopyrrolyl dione end-capped oligothiophene ambipolar semiconductors for thin film- and light emitting transistors.

The design, synthesis and structure-property investigation of a new thienopyrrolyl dione substituted oligothiophene material showing reduced band gap energy, low lying LUMO energy level and ambipolar semiconducting behaviour is described.

Graphene transistors via in situ voltage-induced reduction of graphene-oxide under ambient conditions.

Here, we describe a simple approach to fabricate graphene-based field-effect-transistors (FETs), starting from aqueous solutions of graphene-oxide (GO), processed entirely under ambient conditions. The process relies on the site-selective reduction of GO sheets deposited in between or on the surface of micro/nanoelectrodes. The same electrodes are first used for voltage-induced electrochemical GO reduction, and then as the source and drain contacts of FETs, allowing for the straightforward production and characterization of ambipolar graphene devices.

A successful chemical strategy to induce oligothiophene self-assembly into fibers with tunable shape and function.

Functional supramolecular architectures for bottom-up organic nano- and microtechnology are a high priority research topic. We discovered a new recognition algorithm, resulting from the combination of thioalkyl substituents and head-to-head regiochemistry of substitution, to induce the spontaneous self-assembly of sulfur overrich octathiophenes into supramolecular crystalline fibers combining high charge mobility and intense fluorescence. The fibers were grown on various types of surfaces either as superhelices or straight rods depending on molecular structure.

Trans-A2B-corroles bearing a coumarin moiety--from synthesis to photophysics.

Four dyads comprised of corrole and coumarin units have been synthesised. Three coumarincarboxaldehydes were synthesized and transformed into the corresponding trans-A(2)B-corroles by reaction with 5-(pentafluorophenyl)dipyrromethane. It has been proven that this type of direct condensation can lead to the corresponding corroles in moderate yields.

Light-driven charge separation in isoxazolidine-perylene bisimide dyads.

A series of arrays for light-driven charge separation is presented, in which perylene tetracarboxylic bisimide is the light-absorbing chromophore and electron acceptor, whereas isoxazolidines are colourless electron donors, the electron-releasing properties of which are increased with respect to the amino group by means of the alpha-effect. Charge separation (CS) in toluene over a distance ranging from approximately 10 to approximately 16 A, with efficiencies of approximately 95 to approximately 50 % and CS lifetimes from 300 ps to 15 ns, are demonstrated. In dichloromethane the charge recombination reaction is faster than charge separation, preventing accumulation of the CS state.

Excited-state dynamics in a dyad comprising terpyridine-platinum(II) ethynylene linked to pyrrolidino-[60]fullerene.

A hybrid [Pt((t)Bu(3)terpy)(C[triple bond]C-Ph-C(60))](+) complex (Pt-Fu) wherein a phosphorescent platinum center is linked to fullerene has been prepared using a copper(I)-promoted cross-coupling reaction. The electrochemical and spectroscopic properties were understood in light of the properties of the isolated building blocks and references compounds, Pt and Fu. In particular, in Pt-Fu, the electrochemical studies revealed that the first reduction process is fullerene-based and that the lowest-energy Pt(+)-Fu(-) charge-separated (CS) state lies in the range 2.

Alkylenesulfanyl-bridged bithienyl cores for simultaneous tuning of electronic, filming, and thermal properties of oligothiophenes.

DPY and DPE alkylenesulfanyl-bridged bithienyls were prepared by a highly effective ring-closing reaction via arylalkylsulfonium intermediate and used as inner cores in oligothiophenes. HOMO-LUMO energy levels, conformational flexibility, and intrinsic asymmetry of the cores are reflected in the electronic, film-forming, and thermal properties of the corresponding oligomers.

Polyvinyl-locked versus free quaterthiophene: effect of spatial constraints on the electronic properties of n-hexylquaterthiophene.

A soluble, low-weight fraction of poly(alpha-vinyl,omega-n-hexyl-quaterthiophene), PT4Hex, having n-hexylquaterthiophenes as side-chain groups, is prepared by free-radical polymerization of alpha-vinyl,omega-n-hexyl-quaterthiophene and the corresponding properties compared to those of free di-n-hexylquaterthiophene (T4Hex). Optical analysis (absorption and emission) and X-ray diffraction data indicate that in the polyvinyl-locked architecture the quaterthiophene pendants adopt a cofacial arrangement with a mutual distance close enough for pi-pi orbitals to overlap ( approximately 4 A). As a consequence of the close chain packing, a shift of the reduction potential of about 0.

cis-trans photoisomerization in [Ru(DIP)2(MeOH)2][OTf]2: synthesis, NMR, X-ray structure of the trans-isomer and photophysical properties.

The first trans-ruthenium complex trans-[Ru(DIP)2(MeOH)2][OTf]2 (1b, where DIP = 4,7-diphenyl-1,10-phenanthroline) incorporating a pi-extended ligand was prepared via two methods: either photolysis of cis-[Ru(DIP)2(OTf)2] in MeOH-Et(2)O or via crystallization from MeOH-Et(2)O in direct sunlight. The X-ray molecular structure of is reported and confirmed the trans geometry of the title compound. The cis-trans isomerization process was monitored by 1H-NMR and showed that 1b reverts back to cis-[Ru(DIP)2(MeOH)2][OTf]2 (1a) in methanol-d4 after 15 h at 55 degrees C or several days at room temperature.