Bay-annulated indigo derivatives based on a core of spiro[fluorene-9,9′-xanthene]: Synthesis, photophysical, and electrochemical properties

Synthesis and Properties of a Bay-Annulated-Indigo Tetramer Based on Low-Cost Spiro[Fluorene-9,9′-Xanthene] Core

“…The maximum absorption peaks are located at 596 nm for the solution with a large molar absorption coefficient of 1.5 × 10 5 M −1 cm −1 and at 593 nm for the film, respectively. The almost identical peak positions of maximum absorptions imply weakened intermolecular interactions of 4BAI-SFX benefiting from the 3D molecular geometry [3,20]. According to the absorption edge of 4BAI-SFX in CHCl 3 solution, the band gap was calculated to be 1.80 eV.…”

“…Spiro[fluorene-9,9′-xanthene] ( SFX ) is a new class of 3D aromatic compound which has drawn great interest recently as a core backbone for “eco-friendly green organic semiconductors” due to its merits of “one-pot” preparation and the binary conjugation of fluorene moiety and xanthene moiety [18,19]. In our previous work, two BAI-dimers ( 2,7-BAI-SFX and 2′,7′-BAI-SFX ), appending BAI units on the 2,7- and 2′,7′-positions of SFX , were prepared and studied [20]. Herein, we would like to present the design, synthesis and properties of a BAI tetramer (denoted as 4BAI-SFX ; see Scheme 1 for structure) constructed on the SFX core; the results of photophysical, electrochemistry, and computational study imply that 4BAI-SFX possesses great potential as a low-cost and n -type 3D organic semiconductor.…”

Functional Organic Semiconductors Based on Bay‐Annulated Indigo (BAI)

“…Various aromatic groups can be coupled to 6,6’‐dibromo functionalized BAI through transition metal catalyzed Stille and Suzuki cross‐couplings (Figure ). Thienyl rings at the bay position can be selectively brominated at the 2‐position, opening up another avenue for derivatization . BAI can also be used as a monomer for the synthesis of conjugated polymers, which have been accomplished primarily through Stille coupling.…”