Chemical Identity and Structure

4,7-Bis(5-bromo-4-octylthiophen-2-yl)-5,6-difluorobenzo[c][1,2,5]thiadiazole is a precision-engineered donor–acceptor (D-A) molecular building block. Its architecture places a strongly electron-withdrawing 5,6-difluorobenzo[c][1,2,5]thiadiazole (ffBT) unit at the centre, flanked symmetrically by two 5-bromo-4-octylthiophen-2-yl donor wings.

The two bromine atoms at the terminal positions of the thiophene rings serve as versatile handles for metal-catalysed cross-coupling reactions, including Stille polycondensation, Suzuki–Miyaura coupling, and direct arylation polymerisation (DAP). The n-octyl side chains impart sufficient solubility in common organic solvents (e.g., chloroform, chlorobenzene, THF), facilitating solution-phase polymer synthesis and thin-film processing. The compound is also catalogued under the reference code K0478 by Lumtec / Dairan Chemical.

Role of Fluorination in Electronic Performance

The introduction of two fluorine atoms onto the benzothiadiazole ring to give the ffBT acceptor unit is a well-established strategy in organic semiconductor design. Fluorine's strong electronegativity lowers the LUMO energy level of the acceptor unit relative to the non-fluorinated BT analogue, resulting in a reduced optical band gap and extended light-absorption into longer wavelengths — a desirable property for OPV active layers.

Beyond electronic effects, fluorine atoms participate in non-covalent interactions such as F···H, F···S, and F···π contacts. These non-covalent forces promote planar backbone conformations and closer π–π stacking distances in the solid state, both of which are known to enhance charge-carrier mobility in conjugated polymer films. Consequently, ffBT-based polymers frequently outperform their non-fluorinated BT counterparts in both OPV power conversion efficiency and OFET field-effect mobility.

Synthetic Applications and Cross-Coupling Compatibility

The two terminal C–Br bonds make B290485 a versatile AB₂-type monomer for constructing D-A conjugated polymers via:

• Stille coupling: paired with distannylated donor monomers (e.g., bis(trimethylstannyl)thiophene derivatives) under Pd catalysis.
• Suzuki–Miyaura coupling: paired with bisboronic ester donor monomers, suitable when tin-free conditions are required.
• Direct arylation polymerisation (DAP): exploiting C–H activation of complementary donor units, avoiding the need for pre-functionalised organometallic partners.

In small-molecule synthesis, one or both bromines can be selectively converted via mono-borylation or mono-stannylation to allow asymmetric elaboration. The n-octyl side chains ensure the resulting oligomers and polymers retain adequate solubility for gel-permeation chromatography (GPC) characterisation and solution deposition methods such as spin-coating or blade-coating.

Handling, Storage, and Safety Considerations

As a halogenated organic compound containing a thiadiazole heterocycle, B290485 should be handled in accordance with standard laboratory safety protocols for research-grade organic reagents:

• Storage: Store in a tightly sealed container under inert atmosphere (nitrogen or argon), away from light, heat, and moisture. Low-temperature storage (2–8 °C or −20 °C) is recommended to maintain long-term stability.
• Personal protection: Use nitrile gloves, safety glasses, and a lab coat. Handle in a well-ventilated fume hood.
• Disposal: Dispose of in accordance with local regulations for halogenated organic waste.

Note: A full Safety Data Sheet (SDS) should be consulted prior to use. Specific GHS hazard classifications for this compound should be verified with the current SDS provided by Aladdin Scientific.

Ordering Information

4,7-Bis(5-bromo-4-octylthiophen-2-yl)-5,6-difluorobenzo[c][1,2,5]thiadiazole is available from Aladdin Scientific under SKU B290485. This product corresponds to reference code K0478 in the Lumtec / Dairan Chemical catalogue. For pricing, availability, and bulk enquiries, please contact Aladdin Scientific's sales team or submit a request through the online portal. Researchers requiring a Certificate of Analysis (CoA) or Safety Data Sheet (SDS) may obtain these documents upon request.