Synthesis and Characterization of Star‐Shaped Donor–Acceptor–Donor Structures

Abstract

A Sonogashira coupling reaction led to star‐shaped 1,3,5‐tris({5‐[7‐(thiophen‐2‐yl)benzo[c][1,2,5]thiadiazol‐4‐yl]thiophen‐2‐yl}ethynyl)benzene derivatives. The star‐shaped molecules were optically analyzed, and – depending on their substitution pattern – they displayed bathochromically shifted absorptions, which were compared to their nonlinked arm precursors. The materials displayed a highly interesting morphology in bulk when blended with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM). One derivative formed columnar structures and revealed prospective use in photodiodes.

The role of structural and electronic factors in shaping the ambipolar properties of donor–acceptor polymers of thiophene and benzothiadiazole

“…When BT is incorporated with electron donor units, the extension of the conjugated length appears, due to the occurrence of intarmolecular charge transfer (ICT) in D-A structure [28,29]. These conjugated materials have been synthesized and characterized to enhance the electrochemical and optical properties for instance low HOMO-LUMO gap values, fast switching time, high optical contrast and high conductivity [19,30,31].…”

Synthetic Approaches to Star‐Shaped Molecules with 1,3,5‐Trisubstituted Aromatic Cores

“…Holder and co‐workers established an efficient procedure for the construction of a variety of star‐shaped molecules ( 118 – 120 ) in which a 1,3,5‐triethynyl benzene core was directly connected to highly branched peripheral heteroaromatic units . The key precursors ( 115 – 117 ) were derived from 4,7‐dibromobenzothiadiazole ( 108 ) by employing Suzuki and Stille cross‐coupling reactions, followed by bromination with NBS (Scheme ).…”

“…In this regard, C 3 -symmetrical 1,3,5-triphenylbenzene (26)w as convertedi nto the corresponding1 ,3,5tris(4-iodophenyl)benzene ( 7)b yu sing iodine in the presence of orthoperiodic acid( H 5 IO 6 ). Next, triiodod erivative 7 was subjected to SM cross-coupling with 4-fluorophenylboronic acid (27)u nder palladium catalysis to provide compound 29.…”

Recent Developments in the Synthesis and Applications of 1,2,5-Thia- and Selenadiazoles. A Review

“…107,108 Hexylthiophene-and substituted fluorene-boronic acid pinacol esters 116 were successfully used in the reaction with dibromobenzothiadiazole (112) producing the corresponding 4,7-bis(aryl)-2,1,3-benzothiadiazoles 114 in high yields (Scheme 54). [109][110][111][112][113] …”

“…Sometimes instead of an organic base, a mixture of potassium carbonate and triphenylphosphine was used 155. In contrast to Suzuki and Stille couplings, monoalkynyl derivatives 130 can be obtained from 4,7-dibromo-2,1,3-benzothiadiazole(112) in high yields employing practically the same conditions as those used for the synthesis of dialkynyl benzothiadiazoles, with a smaller amount of terminal alkyne (Scheme 63) 156,157. It was shown that four ethynyl groups can be inserted to benzothiadiazole molecule in one step giving so called "carbon-rich BTD series."…”