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Upstream product

• 1887-60-1 5,6-dimethylbenzo-2,1,3-thiadiazole 
• 3171-45-7 4,5-dimethyl-1,2-phenylenediamine 

Relevant academic research and scientific papers

Chalcogen Bonding “2S–2N Squares” versus Competing Interactions: Exploring the Recognition Properties of Sulfur

Chalcogen bonding (CB) is the focus of increased attention for its applications in medicinal chemistry, materials science, and crystal engineering. However, the origin of sulfur's recognition properties remains controversial, and experimental evidence for supporting theories is still emerging. Here, a comprehensive evaluation of sulfur CB interactions is presented by investigating 2,1,3-benzothiadiazole X-ray crystallographic structures gathered from the Cambridge Structure Database (CSD), Protein Data Bank (PDB), and own laboratory findings. Through the systematic analysis of substituent effects on a subset library of over thirty benzothiadiazole derivatives, the competing interactions have been categorized into four main classes, namely 2S–2N CB square, halogen bonding (XB), S???S, and hydrogen-bonding (HB). A geometric model is employed to characterize the 2S–2N CB square motifs and discuss the role of electrostatic, dipole, and orbital contributions toward the interaction.

Functionalizing benzothiadiazole with non-conjugating ester groups as side chains in a donor-acceptor polymer improves solar cell performance

Herein, the effect of non-conjugated ester functionalization at the 5,6-position of 2,1,3-benzothiadiazole (BT) in a donor (D)-acceptor (A) conjugated polymer (CP) used for photovoltaic devices has been investigated. Positions 5 and 6 of BT were functionalized with methyl acetate groups and the structure property relationship was compared to BT with methyl groups at the 5 and 6 positions in four types of D-A CPs. Alternate co-polymers of newly synthesized methyl and methyl acetate derivatives of BT and Th-BT-Th with commonly used donors such as dithiophene (DTh) and benzodithiophene (BDT) were synthesized using Stille coupling reactions: namely, P(1,2,3,4)-Me and P(1,2,3,4)-Ac. All CPs were extensively characterized using GPC, UV-visible, 1H-NMR, 13C-NMR, TGA and CV. The optimized geometry, along with changes in the dihedral angle upon substitution with acetate groups, was analyzed by density functional theory (DFT) using B3LYP/6-31G(d,p). The side chain ester groups lower the dihedral angle, improve the optical and electrochemical properties of CPs in polymer solar cells (PSCs), improve phase separation of the active layer and performance of the fabricated PSCs compared to methyl counterparts, as investigated for P(1,2,3,4)-Me and P(1,2,3,4)-Ac. Upon fabrication of a BHJ solar cell with ITO/PEDOT:PSS/P-PC71BM/LiF/Al device geometry, CPs with methyl acetate functionalization (P2-Ac, P3-Ac and P4-Ac) resulted in higher PCEs of 1.36%, 1.17% and 0.35%, compared to their methyl counterpart CPs, P2-Me, P3-Me and P4-Me, which exhibited PCEs of 0.9%, 0.54% and 0.31%, respectively. With 1,8-diiodooctane (DIO) as an additive, a higher PCE of 1.96% was achieved for P3-Ac. Atomic force microscopy (AFM) and thin film X-ray diffraction (XRD) were used to determine the impact of side chain ester groups on π-π stacking distance among CP main chains in the film state and the morphology of the active layer of the fabricated PSCs, respectively.

Synthesis and characterization of carbazole-based copolymers containing benzothiadiazole derivative for polymer light-emitting diodes

A new thermally robust electroluminescent (EL) carbazole-based-conjugated copolymer, including poly[3,7-(N-hexylcarbazole)-co-4,7-{5,6-bis(3,7- dimethyloctylo-xymethyl)-2,1,3-(benzothiadiazole)}] (PCz-co-P2C10BT) was synthesized and used to fabricate the efficient polymer light-emitting diodes (PLEDs). The glass transition temperature of the PCz-co-P2C 10BT (105C) was found to be higher than that of poly(9,9- dialkylfluorene) derivatives. We fabricated PLEDs in ITO/PEDOT/light-emitting polymer/Alq3/LiF/Al configuration. The new copolymer was found to have green emission color (523nm). The maximum brightness and external quantum efficiency of PCz-co-P2C10BT were 260 cd/m2 at 14V and 0.22%, respectively.