Polymer supported palladium nanoparticles, generated in situ by Pd(II) reduction under reaction conditions, catalyzed the hydrogenation of nitroarenes to anilines with high efficiency in water at room temperature in the presence of NaBH4. The protocol proved to be highly selective and generally favored the formation of the desired aniline as single product in high yields with short reaction times. TEM analyses revealed that the size distribution of the formed Pd nanocrystals was regulated by the reductant agent. In details, when 1 atm H2 was used as the nitroarene reductant, the in situ generated polymer supported palladium nanoparticles were crystallites with diameters ranging from 6 to 10 nm. On the contrary, when the reaction was carried out in the presence of NaBH4 in water under N2 or air, the formation of Pd nanocrystallites was observed as well, but this time they were smaller (mean size diameter ca. 3 nm) and catalytically more active compared to the palladium nanoparticles formed under 1 atm H2 in the absence of NaBH4. The catalyst displayed excellent recyclability over twelve cycles and no leaching of metal into solution occurred, which made the overall system eco-friendly and economic.

This work demonstrates how the directing ability of the azetidine ring could be useful for regioselective ortho-C-H functionalization of aryl compounds. Robust polar organometallic (lithiated) intermediates are involved in this synthetic strategy. The reagent n-hexyllithium emerged as a safer, yet still effective, basic reagent for the hydrogen/lithium permutation relative to the widely used reagent nBuLi. Two different reaction protocols were discovered for regioselective lithiation at the ortho positions adjacent to the azetidine ring, which served as a toolbox when other competing directing groups were installed on the aromatic ring. The coordinating ability of the azetidine nitrogen atom, as well as the involvement of dynamic phenomena related to the preferential conformations of 2-arylazetidine derivatives, were recognized to be responsible for the observed reactivity and regioselectivity. A site-selective functionalization of the aromatic ring was achieved for aryl azetidines with either coordinatively competent groups (e.g. methoxy) or inductively electron-withdrawing substituents (e.g. chlorine and fluorine). By fine-tuning the reaction conditions, regioselective introduction of several substituents on the aromatic ring could be realized. Several substitution patterns were accomplished, which included 1,2,3-trisubstitution, 1,2,3,4-tetrasubstitution, and 1,2,3,4,5-pentasubstitution, up to the exhaustive substitution of the aromatic ring.

The manuscript describes the design, preparation and characterization of two structurally isomeric random poly(arylene−vinylene)s, the properties of which have been optimized for their use as donor materials in BHJ solar cells. The structure of the polymers was aimed at broadening as much as possible their absorption profile. Poly[9,9-dioctylfluorene− vinylene-co-4,7-dithiophen-2-yl-benzo[1,2,5]thiadiazole−vinylene] (P1) and poly[2,7-dithiophen-2-yl-9,9-dioctylfluorene−vinylene- co-4,7-benzo[1,2,5]thiadiazole−vinylene] (P2) were prepared using the Suzuki−Heck polymerization. The polymers were characterized by elemental analysis, NMR, UV−vis absorption and photoluminescence, cyclic voltammetry, and GPC. The electrochemical characterization of P1 and P2 revealed similar HOMO/LUMO energy levels, although the UV−vis absorption profile of P2 is markedly broader than the one exhibited by P1. The more panchromatic absorption of P2 was explained by DFT and TDDFT calculations showing that the model systems, contributing together to the description of the random polymeric structure, exhibited different calculated excitation energies, that cover a broader portion of the absorption spectrum. In BHJ solar cells, the broadness of the absorption strongly influences the BHJ solar cell performances of P2 compared to P1 leading to higher short circuit currents and to a 3-fold higher power conversion efficiency. The PCE value (0.6%) obtained with P2 is in line with those obtained for other poly(heteroarylene−vinylene)s donors and is amenable to improvement by optimizing the device construction (PC61BM amount in the blend or use of annealing processes). These results demonstrate how combination of a suitable choice of the sequence of aryl units together with the potentialities offered by random polymers, can be useful tools in the design of new light-harvesting polymers in BHJ.

Extensive intramolecular π-conjugation is considered to be requisite in the design of organic semiconductors. Here, two inkjet pigments, epindolidione and quinacridone, that break this design rule are explored. These molecules afford intermolecular π-stacking reinforced by hydrogen-bonding bridges. Air-stable organic field effect transistors are reported that support mobilities up to 1.5 cm2/Vs with T80 lifetimes comparable with the most stable reported organic semiconducting materials.

OFETs based on new solution-processed ester functionalized 9,10-ter-anthrylene-ethynylenes show a mobility increase of four orders of magnitude, leading to mobilities as high as 4.9 × 10-2 cm 2 V-1 s-1 if the deposited film is annealed before contact deposition. The behavior is ascribed to an increase in film order at the dielectric/semiconductor interface as revealed by X-ray studies.

The organocatalytic synthesis of new α-acyloxy-3-arylpropionic thioesters has been accomplished providing some enantioenriched important aryllactic acid derivatives in good yield and enantioselectivities.

Organic pigments such as indigos, quinacridones, and phthalocyanines are widely produced industrially as colorants for everyday products as various as cosmetics and printing inks. Herein we introduce a general procedure to transform commercially available insoluble microcrystalline pigment powders into colloidal solutions of variously sized and shaped semiconductor micro- and nanocrystals. The synthesis is based on the transformation of the pigments into soluble dyes by introducing transient protecting groups on the secondary amine moieties, followed by controlled deprotection in solution. Three deprotection methods are demonstrated: thermal cleavage, acid-catalyzed deprotection, and amine-induced deprotection. During these processes, ligands are introduced to afford colloidal stability and to provide dedicated surface functionality and for size and shape control. The resulting micro- and nanocrystals exhibit a wide range of optical absorption and photoluminescence over spectral regions from the visible to the near-infrared. Due to excellent colloidal solubility offered by the ligands, the achieved organic nanocrystals are suitable for solution processing of (opto)electronic devices. As examples, phthalocyanine nanowire transistors as well as quinacridone nanocrystal photodetectors, with photoresponsivity values by far outperforming those of vacuum deposited reference samples, are demonstrated. The high responsivity is enabled by photoinduced charge transfer between the nanocrystals and the directly attached electron-accepting vitamin B2 ligands. The semiconducting nanocrystals described here offer a cheap, nontoxic, and environmentally friendly alternative to inorganic nanocrystals as well as a new paradigm for obtaining organic semiconductor materials from commercial colorants.

The regioselective lithiation-functionalization of 2-arylazetidines has been explored. The nature of the N-substituent is mainly responsible for a regioselectivity switch. ortho-Lithiation occurred, using hexyllithium as a greener base, in N-alkylazetidines, while α-benzylic lithiation has been observed with N-Boc azetidines.

A strategy for the stereoselective functionalization of thietane 1-oxide has been developed. Mono (C2 substituted) and doubly (C2, C4 disubstituted) functionalized thietanes have been obtained from the readily available thietane 1-oxide by using the corresponding organometallic intermediates that reacted with electrophiles leaving intact the 4-membered ring.

Among the metal oxide semiconductors, ZnO has been widely investigated as a channel in thin film transistors (TFTs) due to its excellent electrical properties, optical transparency and simple fabrication via solution processed techniques. Herein, we are reporting a solution processable ZnO based thin-film transistor, gated through a liquid electrolyte having an ionic strength comparable to that of a physiological fluid. The surface morphology and chemical composition of the ZnO films upon exposure to water and phosphate buffer solution (PBS), are discussed in terms of operation stability and electrical performance of the ZnO TFT devices. Improved device characteristics upon exposure to PBS are associated with the enhancement of the oxygen vacancies in ZnO lattice, possibly due to Na+ doping. Moreover, dissolution kinetics of ZnO thin film in liquid electrolyte opens to possible applicability of these devices as active element in “transient” implantable systems.