1,4-Dihydropyrrolo[3,2-b]Pyrroles Containing New A-D-A System: Synthesis and Investigation of Their Photophysical Properties.

Herein, new tetraarylpyrrolo[3,2-b]pyrroles (TAPP) containing different substituents (4a-c, 5a-c) on the N-phenyl rings were synthesized in high yields using a one-pot method. The 3,6 positions of the pyrrolopyrol ring of the 4a-c compound were formylated by Vilsmeier-Haack reaction to synthesize a new pyrrolopyrol compound containing the acceptor-donor-acceptor (A-D-A) system (5a-c). The photophysical properties of all obtained derivatives were investigated in different solvents. According to the results obtained, the absorptions of derivatives 4a-c were recorded around 400 nm and their emission intensities appeared around 450 nm. The absorption intensities of derivatives 4b and 5b were recorded as 400 nm and 350 nm, respectively, while their emission intensities were observed as 455 and 440. In the A-D-A system formed as a result of the bonding of electron-withdrawing formyl groups at position 3,6 of the TAPP structure, a high Stokes shift occurred, while 50 nm hypsochromic shifts were observed in its absorption.