Supramolecular Weaving by Halogen-Bonding in Functionality-Rich Hexasubstituted Aromatic Synthons.

Hexasubstituted benzenes are interesting platforms for the generation of functional materials, whose applications span from supramolecular recognition to organic electronics. Their synthesis is difficult to achieve by controlling multiple substitution steps of all hydrogen atoms on the aromatic benzene skeleton, so, often, cycloaddition reactions from disubsituted alkynes are used. In this work, we report a novel, straightforward route to -symmetrical hexasubstituted aromatic synthons with a diverse and rich pattern of functionalities, and we report about their packing mode in the crystals, in which, unprecedentedly, directional, strong halogen bonding interactions are capable of forming bidimensional supramolecular weaving.

Recent Advances in Non-Fullerene Acceptors of the IDIC/ITIC Families for Bulk-Heterojunction Organic Solar Cells.

The introduction of the IDIC/ITIC families of non-fullerene acceptors has boosted the photovoltaic performances of bulk-heterojunction organic solar cells. The fine tuning of the photophysical, morphological and processability properties with the aim of reaching higher and higher photocurrent efficiencies has prompted uninterrupted worldwide research on these peculiar families of organic compounds. The main strategies for the modification of IDIC/ITIC compounds, described in several contributions published in the past few years, can be summarized and classified into core modification strategies and end-capping group modification strategies.

One-Pot Regiodirected Annulations for the Rapid Synthesis of π-Extended Oligomers.

We demonstrate the broad applicability of the annulation protocol combining, in one pot, a direct arylation and cross aldol condensation for the straightforward synthesis at gram-scale of π-extended thiophene-based scaffolds. The regiospecific direct arylation drives the subsequent cross-aldol condensation proceed under the same basic conditions, and the overall protocol has broad applicability in the synthesis of extended aromatics wherein the thiophene ring is annulated with furans, pyridines, indoles, benzothiophenes, and benzofurans. These scaffolds can be further elaborated into π-extended, highly fluorescent oligomers with a central deficient benzothiadiazole unit with up to nine aromatic rings through coupling reactions.

A relatively wide-bandgap and air-stable donor polymer for fabrication of efficient semitransparent and tandem organic photovoltaics.

Organic photovoltaics (OPVs) have attracted tremendous attention in the field of thin-film solar cells due to their wide range of applications, especially for semitransparent devices. Here, we synthesize a dithiaindacenone-thiophene-benzothiadiazole-thiophene alternating donor copolymer named poly{[2,7-(5,5-didecyl-5H-1,8-dithia-as-indacenone)]-alt-[5,5-(5',6'-dioctyloxy-4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]} (PDTIDTBT), which shows a relatively wide bandgap of 1.82 eV, good mobility, and high transmittance and ambient stability.

Light Management in Organic Photovoltaics Processed in Ambient Conditions Using ZnO Nanowire and Antireflection Layer with Nanocone Array.

Low carrier mobility and lifetime in semiconductor polymers are some of the main challenges facing the field of organic photovoltaics (OPV) in the quest for efficient devices with high current density. Finding novel strategies such as device structure engineering is a key pathway toward addressing this issue. In this work, the light absorption and carrier collection of OPV devices are improved by employment of ZnO nanowire (NW) arrays with an optimum NW length (50 nm) and antireflection (AR) film with nanocone structure.

Synthesis of Dithienocyclohexanones (DTCHs) as a Family of Building Blocks for π-Conjugated Compounds in Organic Electronics.

The development and widespread application of organic electronic devices require the availability of simple and cost-effective suitable materials. In this study, the preparation of a new class of conjugated compounds on the basis of a dithienocyclohexanone (DTCH) core is reported. Several synthetic strategies for the preparation of dialkyl DTCH derivatives are explored, with special emphasis on the establishment of a sustainable synthetic access.

Domino Direct Arylation and Cross-Aldol for Rapid Construction of Extended Polycyclic π-Scaffolds.

Five-membered aromatic heterocycles are a ubiquitous skeleton of π-conjugated organic compounds, and their incorporation requires synthetic protocols that are not easily industrially sustainable or scalable. Improved methodologies for their insertion into π-scaffolds are therefore necessary. We report an efficient and scalable protocol involving a one-pot cross-Aldol direct arylation reaction protocol for the rapid construction of thiophene- and furan-based π-extended organic materials.

Direct Arylation Strategies in the Synthesis of π-Extended Monomers for Organic Polymeric Solar Cells.

π-conjugated macromolecules for organic polymeric solar cells can be rationally engineered at the molecular level in order to tune the optical, electrochemical and solid-state morphology characteristics, and thus to address requirements for the efficient solid state device implementation. The synthetic accessibility of monomers and polymers required for the device is getting increasing attention. Direct arylation reactions for the production of the π-extended scaffolds are gaining importance, bearing clear advantages over traditional carbon-carbon forming methodologies.

Conjugated Thiophene-Fused Isatin Dyes through Intramolecular Direct Arylation.

We report on the design, synthesis, and properties of innovative, planar, π-conjugated compounds in which a thiophene ring is fused with the skeleton of the naturally occurring dye isatin. The synthesis is achieved in high yields making use of an intramolecular direct arylation reaction as the key step, making the overall process potentially scalable. The synthetic sequence has been demonstrated also for an isatin bearing fluorine substituents on the aromatic ring.

Gold-catalyzed reactions of 2-alkynyl-phenylamines with alpha,beta-enones.

[reaction: see text] The gold-catalyzed reaction of 2-alkynyl-phenylamines with alpha,beta-enones represents a new general one-pot entry into C-3-alkyl-indoles by sequential reactions. Gold-catalyzed sequential cyclization/alkylation, N-alkylation/cyclization, or N-alkylation/cyclization/alkylation reactions leading to different indoles can be directed by changing the 2-alkynyl-phenylamine 1/alpha,beta-enone 3 ratio and the reaction temperature. Unusual gold-catalyzed rearrangement reaction of indoles are observed at 140 degrees C.

Sequential amination/annulation/aromatization reaction of carbonyl compounds and propargylamine: a new one-pot approach to functionalized pyridines.

A general one-pot synthesis of pyridines 4a-t from the reaction of dialkyl acyclic/cyclic ketones 1a-i, methyl, aryl/heteroaryl ketones 1m-r, and aldehydes bearing alpha-hydrogens 1s,t with propargylamine 2 is described. Gold and copper salts are efficient catalysts for the reaction of ketones with 2. The formation of the pyridines 4 is suggested to proceed through the sequential amination of carbonyl compounds followed by regioselective 6-endo-dig cyclization of the N-propargylenamine (N-propargyldienamine) intermediate 3(5) and aromatization reaction.