Scalable Synthesis of Naphthothiophene and Benzodithiophene Scaffolds as π-Conjugated Synthons for Organic Materials

Anthradithiophene (ADT)-Based Polymerized Non-Fullerene Acceptors for All-Polymer Solar Cells

Realizing efficient all-polymer solar cell (APSC) acceptors typically involves increased building block synthetic complexity, hence potentially unscalable syntheses and/or prohibitive costs. Here we report the synthesis, characterization, and implementation in APSCs of three new polymer acceptors P1-P3 using a scalable donor fragment, bis(2-octyldodecyl)anthra[1,2-b : 5,6-b']dithiophene-4,10-dicarboxylate (ADT) co-polymerized with the high-efficiency acceptor units, NDI, Y6, and IDIC. All three copolymers have comparable photophysics to known polymers; however, APSCs fabricated by blending P1, P2 and P3 with donor polymers PM5 and PM6 exhibit modest power conversion efficiencies (PCEs), with the champion P2-based APSC achieving PCE=5.64 %. Detailed morphological and microstructural analysis by AFM and GIWAXS reveal a non-optimal APSC active layer morphology, which suppresses charge transport. Despite the modest efficiencies, these APSCs demonstrate the feasibility of using ADT as a scalable and inexpensive electron rich/donor building block for APSCs.

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 C₃-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.

A Sustainable Synthetic Approach to the Indaceno[1,2-b:5,6-b′]dithiophene (IDT) Core through Cascade Cyclization–Deprotection Reactions

Bulk heterojunction organic solar cells (BHJs) are competitive within the emerging photovoltaic technologies for solar energy conversion because of their unique advantages. Their development has been boosted recently by the introduction of nonfullerene electron acceptors (NFAs), to be used in combination with a polymeric electron donor in the active layer composition. Many of the recent advances in NFAs are attributable to the class of fused-ring electron acceptors (FREAs), which is now predominant, with one of the most notable examples being formed with a fused five-member-ring indaceno[1,2-b:5,6-b′]dithiophene (IDT) core. Here, we propose a novel and more sustainable synthesis for the IDT core. Our approach bypasses tin derivatives needed in the Stille condensation, whose byproducts are toxic and difficult to dispose of, and it makes use of cascade reactions, effectively reducing the number of synthetic steps.

Regioselective Synthesis of Naphthothiophenes by Pd Catalyzed Cross-Coupling Reactions and Alkyne-Carbonyl Metathesis

Naphthothiophenes were prepared from commercially available 2,3-dibromothiophenes in two steps by one-pot Suzuki/Sonogashira or Sonogashira/Suzuki coupling reactions, followed by intramolecular alkyne-carbonyl-metathesis reactions. The final cyclization reaction proceeds in the presence of p-toluenesulfonic acid and provides a rapid access to two series of isomeric naphthothiophenes.

Aminothiaindanone as an Accessible Scaffold for a Three-Point Chemical Diversity

Aminothiaindanone heterocycle appears to be a scaffold of interest in medicinal chemistry. To increase the chemical diversity in this series, the introduction of three-point chemical diversity on the cyclopenta[b]thiophen-4-one scaffold was explored. About thirty newly functionalized thiophene-containing bicycles were obtained using various chemical reactions, paving the way for novel possibilities in medicinal chemistry projects.