Synthesis, characterization and optoelectronic properties of pyrrolopyrazine based Y-shaped color-tunable dipolar molecules

A regioselective approach for the synthesis of functionalized dipolar Y-shaped chromophores is demonstrated. A series of dipolar pyrrolopyrazine based molecules were prepared in a straightforward manner. The key step in the preparation of the chromophores involves two-fold Sonogashira coupling reaction between the pyrrolopyrazine core and acetylene derivatives. Different electron -donors, including, NH2, NMe2 OMe and CF3, CN acceptors were incorporated into the chromophores. By adjusting the substituents at 2, 3, and 6-position of the pyrrolopyrazine, dipolar tunable molecules with wide emission band are synthesized. The optical, thermal, and electrochemical properties of the materials are analysed and the results are supported with the DFT calculations. The preliminary studies of these engineered Y-shaped molecules indicate their potential as new building blocks in the fields of optoelectronic devices.