A Simple and Efficient Route to N-Functionalized Dithieno[3,2-b:2‘,3‘-d]pyrroles:  Fused-Ring Building Blocks for New Conjugated Polymeric Systems

Abstract

A general synthetic route has been developed for the simple and efficient preparation of N-functionalized dithieno[3,2-b:2',3'-d]pyrroles. These synthetic methods utilize N-functionalized N-(3'-thienyl)-3-aminothiophenes produced from the Pd-catalyzed amination of 3-bromothiophene with primary amines, followed by a one-pot bromination/cyclization process. This combination allows the convenient preparation of a variety of N-functionalized dithieno[3,2-b:2',3'-d]pyrroles (where substituent = hexyl, octyl, decyl, tert-butyl, and p-hexylphenyl) in good yield (65-82%). Characterization of the structure and reactivity of this class of compounds is also described, including electrochemical and photophysical data for all compounds and X-ray structural data for the octyl-, tert-butyl-, and p-hexylphenyl-functionalized compounds.

Synthesis and Chain‐Length Dependence of the Electronic Properties of π‐Conjugated Dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) Oligomers

“…DTP and its N-alkyl substituted derivatives have been reported to have very low emission quantum yield (f em ), typically 1-2 Â 10 À3 . [7,23] As shown in Figure 2, the emission spectra of compounds 2 and 3 exhibit a better resolved vibrational fine structure than absorption spectra, suggesting a more rigid geometry in the singlet excited state than in the ground state. Both compounds show high f em values (37 and 72% respectively), higher than the corresponding polymer (0.27).…”

“…(DTP) has recently attracted particular interest as donor building block for functional p-conjugated systems [7][8][9][10][11] and LG polymers. [4,[12][13][14][15] In addition to rigidifying the structure, the bridging electron donor amino group confers on the DTP structure some analogy with carbazole of triphenylamine and can thus be expected to contribute to improving the hole-transport properties of the material in which it is incorporated.…”

Electronic Structures and Spectroscopic Characters of Modified Oligo(alkylenedioxypyrrole)

“…5 The bond lengths of C (3)-O (6) and O(6)-C(7) in compound 1 are 0.138 and 0.144 nm, respectively. The energy gaps of compounds 1-5 (Table 1) are gradually decreased as the chain length increases.…”

“…3,4 The pyrrole structure in conjugated polymers can reduce the oxidation potential in the synthesis of dithienopyrrole. 5 Pyrrole and thiophene can be utilized to form lock copolymers, in which N-methylpyrrole rings cause large rotational defects. 6 Carboxylated pyrrole is successfully polymerized on a Pt electrode to get the deposition of the corresponding conductive polymer.…”

Synthesis and Polymerization of Fused‐Ring Thienodipyrrole Monomers

“…A promising strategy to generate semiconducting polymers with improved optoelectronic properties is the synthesis of polymers containing fused-ring building blocks. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] The incorporation of fused rings generates a more rigid and planar backbone, enhancing the π conjugation and lowering the band gap of the polymers. Benzo [1,2-…”