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Direct arylation of 5-octylthieno[3,4-c]pyrrole-4,6-dione with a series of functionalized aryl iodides via C–H bond activation is demonstrated in a deep eutectic solvent made of choline chloride and urea in non-anhydrous conditions and without exclusion of air. This is the first demonstration of a thiophene–aryl coupling via direct arylation in deep eutectic solvents.

In this article we discuss synthetic routes to organic conjugated oligomers and polymers bearing triple C-C bonds that have been recently developed in our laboratories, based on Pd-catalyzed Csp-Csp2 coupling reactions. Experimental protocols have been tuned to face synthetic challenges such as the presence in the main conjugated backbone of multifunctional substituents or uncommon conjugated units. The relevance of the obtained products in terms of properties and applications is also shortly mentioned.

This review reports a survey of our recent results on the synthesis of arylenevinylene polymers and oligomers selectively functionalized with fluorine atoms on aromatic and/or vinylene units. The synthetic methods developed are based on Pd-catalyzed organometallic cross-coupling reactions and in particular on the Stille coupling between vinyl organotin derivatives and aromatic halides. Several compounds have been synthesized, which differ for the number and position of the fluorine atoms on the conjugated backbone, even combined with other functional groups. The effects of fluorination on optical properties both in solution and solid state are discussed.

The interaction of hydrogen with gold nanoparticles (Au NPs) and gold thin films also functionalized with thiols is investigated. Au NPs deposited on silicon substrates by radio frequency sputtering of a gold target and gold thin films have been exposed to a remote H2plasma and subsequently functionalized by the aromatic (4-methoxyterphenyl-3″,5″-dimethanethiol) and aliphatic (dodecanethiol) thiols. The impact of hydrogenation on changes of the charge on gold surfaces and nanoparticles, on the kinetics of the thiol self-assembled monolayer (SAM) formation, and on the density of the resulting SAMs has been investigated combining spectroscopic ellipsometry (SE), Raman spectroscopy, and surface potential Kelvin probe microscopy (SP-KPM) in conjunction with noncontact atomic force microscopy (AFM). We found that remote H2plasma pretreatments of gold surfaces are effective in improving thiolate adsorption, making SAMs more uniform and densely packed. We also demonstrate that hydrogenation of nanoparticles improves stability of thiol functionalized Au NPs, avoiding their aggregation. Additionally, we demonstrate that a remote H2plasma processing is also effective in the selective removal of the carbon chain and of sulfur atoms from gold surfaces, therefore allowing tailoring of their optical and chemical properties.

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 1by 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.

There has been growing interest in developing new semiconducting polymers for applications in optoelectronics (OLEDs) due to their exceptional processability and appealing characteristic of manipulating electronic and optical properties by tuning of molecular structure and self-assembling. This study is an investigation on the interplay among supermolecular organization and optical properties of thin films of the poly[2-(2-ethylhexyloxy)-5-methoxy]-1, 4-phenylenedifluorovinylene (MEH-PPDFV) conjugated polymer, which has fluorinated vinylene units. This interplay is elucidated exploiting atomic force microscopy, spectroscopy ellipsometry, photoluminescence and electroluminescence. Thin films of MEH-PPDFV have been deposited by drop casting on indium-tin-oxide (ITO), quartz and glass substrates. The dependence of polymer chains self-organization and morphology on substrate surface is presented. Furthermore, it is demonstrated that the presence of F-atoms in the vinylene units of the MEH-PPDFV yields a blue optical band gap with the maximum of the fundamental HOMO-LUMO transition at 331 nm and photoluminescence at 458 nm. The OLED built with the above polymer shows a very stable blue-greenish electroluminescence that is also achieved at 504 nm.

Functionalization with fluorine atoms represents a versatile structural modification to finely tune both the emission colour and the electronic properties of organic and organometallic electroluminescent compounds. This paper reports an overview of our systematic investigation on the design and synthesis of the fluorinated version of two important classes of materials for organic light emitting diodes (OLEDs), namely poly(arylenevinylene)s and phosphorescent phenylpyridine Iridium complexes. Synthetic pathways based on organometallic methodologies affording selectively fluorinated molecular structures will be discussed together with a summary of the effect of fluorination on the optical properties of the resulting materials. In particular we will highlight the possibilities offered by the organometallic methodologies as straightforward and resourceful tools to provide a wide series of fluorinated molecular architectures with high regio- and stereoselectivity, mild experimental conditions and good yields.

A method of direct lipid analysis by MALDI mass spectrometry in intact membranes, without prior extraction/separation steps, is described. The purple membrane isolated from the extremely halophilic archaeon Halobacterium salinarumwas selected as model membrane. Lyophilized purple membrane were grinded with 9-aminoacridine (9-AA) as dry matrix, and the powder mixture was crushed in a mechanical die press to form a thin pellet. Small pieces of the pellet were then attached to the MALDI target and directly analyzed. In parallel, individual archaebacterial phospholipids and glycolipids, together with the total lipid extract of the purple membrane, were analyzed by MALDI-TOF/MS using 9-AA as the matrix in solution. Results show that 9-AA represents a suitable matrix for the conventional MALDI-TOF/MS analysis of lipid extracts from archaeal microorganisms, as well as for fast and reliable direct dry lipid analysis of lyophilized archaebacterial membranes. This method might be of general application, offering the advantage of quickly gaining information about lipid components without disrupting or altering the membrane matrix.

The synthesis and photophysical and electrochemical characterisation of new heteroleptic iridium complexes with electron‐withdrawing sulfonyl groups and fluorine atoms bound to phenylpyridine ligands are reported. The emission energy of these materials strongly depends on the position of the sulfonyl groups and on the number of fluorine substituents. A 90 nm wide tuning range of photoluminescence from the blue‐green (λem=468 nm) of iridium(III)bis[2‐(4′‐benzylsulfonyl)phenylpyridinato‐N,C2′][3‐(pentafluorophenyl)‐pyridin‐2‐yl‐1,2,4‐triazolate] to the orange (λem=558 nm) of iridium(III)bis[2‐(3′‐benzylsulfonyl)phenylpyridinato‐N,C2′](2,4‐decanedionate) has been achieved. Emission quantum yields ranging from 47 to 71 % have also been found for degassed solutions of the complexes, and a surprisingly high value of 16 % was recorded for iridium(III)bis[2‐(5′‐benzylsulfonyl‐3′,6′‐difluoro)phenylpyridinato‐N,C2′](2,4‐decanedionate) in air‐equilibrated dichloromethane. A unusual stereochemistry of the benzylsulfonyl‐substituted dimer and heteroleptic complexes has been detected by 1H NMR spectroscopy, and is characterised by the mutual cisdisposition of the pyridyl nitrogen atoms of the phenylpyridine ligands, which differs from the most common transarrangement reported in the literature.

Poly(arylenevinylene) polymers bearing fluorine atoms in the vinylene units were obtained by a Stille cross-coupling reaction of (E)-(1,2-difluoro-1,2-ethenediyl)bis(tributylstannane) with diiodoaryl derivatives. The introduction of fluorine atoms on the double bond of the stannane leads to polymers with relatively high molecular weights. Furthermore, the presence of fluorinated vinylene units changes the optical properties of the polymers and shifts the emission towards the blue region of the visible spectrum. A fluorinated analogue of MEH-PPV was obtained, and it shows photoluminescence that is considerably blueshifted, also in the solid state, relative to that found for nonfluorinated MEH-PPV and to other PPVs with fluorinated double bonds.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

There has been growing interest in developing new semiconducting polymers for applications in optoelectronics (OLEDs) due to their exceptional processability and appealing characteristic of manipulating electronic and optical properties by tuning of molecular structure and self-assembling. This study is an investigation on the interplay among supermolecular organization and optical properties of thin films of the poly[2-(2-ethylhexyloxy)-5-methoxy]-1, 4-phenylenedifluorovinylene (MEH-PPDFV) conjugated polymer, which has fluorinated vinylene units. This interplay is elucidated exploiting atomic force microscopy, spectroscopy ellipsometry, photoluminescence and electroluminescence. Thin films of MEH-PPDFV have been deposited by drop casting on indium-tin-oxide (ITO), quartz and glass substrates. The dependence of polymer chains self-organization and morphology on substrate surface is presented. Furthermore, it is demonstrated that the presence of F-atoms in the vinylene units of the MEH-PPDFV yields a blue optical band gap with the maximum of the fundamental HOMO-LUMO transition at 331 nm and photoluminescence at 458 nm. The OLED built with the above polymer shows a very stable blue-greenish electroluminescence that is also achieved at 504 nm.

Functionalization with fluorine atoms represents a versatile structural modification to finely tune both the emission colour and the electronic properties of organic and organometallic electroluminescent compounds. This paper reports an overview of our systematic investigation on the design and synthesis of the fluorinated version of two important classes of materials for organic light emitting diodes (OLEDs), namely poly(arylenevinylene)s and phosphorescent phenylpyridine Iridium complexes. Synthetic pathways based on organometallic methodologies affording selectively fluorinated molecular structures will be discussed together with a summary of the effect of fluorination on the optical properties of the resulting materials. In particular we will highlight the possibilities offered by the organometallic methodologies as straightforward and resourceful tools to provide a wide series of fluorinated molecular architectures with high regio- and stereoselectivity, mild experimental conditions and good yields.

2,5-Dialkoxypoly(p-phenyleneethynylene) (3) functionalized with N-t-BOC-l-phenylalanine molecules was synthesized by Pd-catalyzed reaction of dioctyloxybis(trimethylsilyl)ethynylbenzene (1) with aromatic diiodide 2linked to two amino acid units by six carbon atoms alkoxy chains. Optical properties were investigated both in solution and in the solid state (as thin films) by absorption, fluorescence and chiroptical spectroscopies (CD and CPL). Polymer 3, that represents one of few fully characterized dialkoxy-substituted PAEs, is also the first example of a poly(aryleneethynylene) (PAE) with amino acidic chiral pendants.

Solution processed Langmuir−Schäfer and cast thin films of regioregular poly(2,5-dioctyloxy-1,4-phenylene-alt-2,5-thienylene) are investigated as transistor active layers. The study of their field-effect properties evidences that no transistor behavior can be seen with a cast film channel material. This was not surprising considering the twisted conformation of the polymer backbone predicted by various theoretical studies. Strikingly, the Langmuir−Schäfer (LS) thin films exhibit a field-effect mobility of 5 × 10-4 cm2,5·s, the highest attained so far with an alkoxy-substituted conjugated polymer. Extensive optical, morphological, and structural thin-film characterization supports the attribution of the effect to the longer conjugation length achieved in the Langmuir−Schäfer deposited film, likely due to an improved backbone planarity. This study shows that a technologically appealing deposition procedure, such as the LS one, can be exploited to significantly improve the inherently poor field-effect properties of twisted conjugated backbones. This achievement could promote the exploitation for electronic, and possibly sensing, applications of the wealth of opportunities offered by the alkoxy substitution on the phenylene units for convenient tailoring of the phenylene−thienylene backbone with molecules of chemical and biological interest.

Homoleptic Ir(Fnppy)3and heteroleptic (Fnppy)2Ir(acac) complexes (n= 3: F3ppy = 2-(3′,4′,6′-trifluorophenyl)pyridine; n= 4: F4ppy = 2-(3′,4′,5′,6′-tetrafluorophenyl)pyridine; acac = acetylacetonate) have been synthesized and their spectroscopic properties investigated. The homoleptic complexes exist as two stereoisomers, facial (fac) and meridional (mer), that have been isolated and fully characterized. Their electrochemical and photophysical properties have been studied both in solution and in the solid state and electroluminescent devices have been fabricated. The emissive layers in devices have been obtained mixing the iridium complexes with a PVK [poly(9-vinylcarbazole)] host matrix, in the presence of the electron carrier Bu-PBD [2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole]. The application of a voltage (5.0–6.5 V) between the electrodes of devices leads to electro-generated blue luminescence which has similar energy to the solution emissions. Interestingly, the stability of the devices made with the homoleptic fluorinated iridium complexes strongly depends on the stereochemistry of these phosphors and high (up to 5.5%) external quantum efficiencies for the faccomplexes are measured.

The present report illustrates the response to osmotic stress of an extreme halophilic archaeon, Halorubrumsp., isolated from the saltern ponds of Margherita di Savoia in southern Italy. The hypotonic stress induces relevant changes in the membrane lipid composition: archaeal cardiolipin content markedly increases, whereas phosphatidylglycerol (PG) decreases. Membranes isolated from this archaeon after cell disruption by osmotic shock are highly enriched in archaeal cardiolipin and reveal the presence of a novel phospholipid. Electrospray ionization mass spectrometry and NMR analyses revealed that this novel lipid has the structure of a sulfo-diglyco-diether-phosphatidic acid, i.e., a phospholipid dimer or a novel cardiolipin analogue. As NMR analyses showed that the sugars in the novel phospholipid dimer are the same and in the same order of a sulfated diglycosyl diphytanylglycerol diether (S-DGD-5) present as a major lipid component in the archaeon membranes, the novel phospholipid dimer was named S-DGD-5-PA.

A copolymer of 2,3,5,6-tetrafluoro-1,4-phenylenevinylene and 2,5-dioctyloxy-1,4-phenylenevinylene [co(TFPV-DOPV)], containing more than 60% of tetrafluorophenylenevinylene monomeric units, was synthesized by the Stille cross-coupling reaction. Its linear and nonlinear optical properties were investigated. Linear absorption and photoluminescence measurements performed on thin films and solution indicate interchain migration upon excitation. The Z-scan technique was used to evaluate the third-order nonlinear susceptibility at λ = 1064 nm. A very high refractive nonlinearity (n2 = (−10 ± 2) × 10⁻¹² cm² · W⁻¹) was measured with a value one order of magnitude larger than that of the corresponding dialkoxy-substituted homopolymer.

The correlation between the optical properties and microstructural parameters of different poly(arylenephenylene) thin films, deposited by spin-coating, is investigated by spectroscopic ellipsometry. Conjugated polymer films are found to be anisotropic. They are birefringent, with a higher refractive index in the plane of the film than perpendicular to it. This anisotropy is due to a preferential in-plane orientation of the polymer chains. The dependence of both the in-plane and out-of-plane optical constants of the polymeric thin films and of the fundamental π−π* transition on the structure of the chain backbone are studied. The change of the π−π* transition energy of the polymers from solution to thin film and its correlation with the molecular structure are investigated as indicative of interchain interactions.

Results of special interest in the field of organometallic chemistry directed towards the synthesis of conjugated oligomers and polymers are reviewed. Methodologies widely employed in the synthesis of well-defined molecules and based on the transition metal catalyzed coupling reactions of various organometallic B, Sn, Si, Mg and Zn reagents have been more recently extended to build up poly- or oligo-meric conjugated molecular architectures. Although the focus of the present work is on transition metal cross-coupling or homo-coupling processes, other useful organometallic routes, such as metathesis reactions and acetylene polymerization, have also been dealt with. Owing to their higher versatility with respect to the non-organometallic processes commonly used for the synthesis of these materials, the approaches presented allow the realization of more complex molecular structures, which are nowadays required in many electronic and optoelectronic applications. The use of organometallic strategies has been discussed from a synthetic organic chemist's point of view, and advantages and limitations of the different methodologies reviewed have been highlighted. Some attention has also been paid to the properties of the resulting materials and to their dependence on the procedure followed and the framework obtained.

A new and general methodology for the synthesis of conjugated polymers presenting a variety of structural features is described. The methodology is based upon the palladium-catalyzed coupling reaction of a bis(1-trimethylsilylethenyl)benzene with arenebisdiazonium tetrafluoroborates. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2002)

In this study we show that thermotolerance and thermoresistance of the yeast Saccharomyces cerevisae is enhanced when cells are in colonial condition. We also describe a method to select stable thermoresistant mutants which produce colonies from single plated cells at a temperature 2.5 °C higher than the maximum growth temperature of their parental strain.

Palladium-catalysed cross-coupling between aromatic bis-organomagnesium reagents and aromatic dihalides has been experimentally evaluated as a general methodology for the synthesis of soluble conjugated polymers such as poly(p-phenylene)s 6 and 7, poly(p-terphenylenevinylene) 8, poly(phenylenethiophene) 9 and poly(phenylenepyridine) 10. Appropriate experimental conditions were first found in model reactions and then applied to the synthesis of polymers. Molecular mass values were determined both by GPC and by MALDI-TOF spectrometry. The latter technique also permitted accurate determination of the terminal groups of the polymeric chains. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)