Synthesis of 3,4-biaryl-2,5-dichlorothiophene through suzuki cross-coupling and theoretical exploration of their potential applications as nonlinear optical materials

We report herein the efficient one-pot synthesis of 3,4-biaryl-2,5-dichlorothiophene derivatives (2a-2i) via a palladium-catalyzed Suzuki cross-coupling reaction. A series of thiophene derivatives were synthesized, starting from 3,4-dibromo-2,5-dichlorothiophene (1) and various arylboronic acids using Pd(PPh₃)₄ and K₃PO₄ with moderate to good yields. For further insights about the structure and property relationship, density functional theory (DFT) calculations were performed. A relaxed potential energy surface (PES) scan was performed to locate the minimum energy structure. A frontier molecular orbitals analysis was performed to explain the reactivity of all synthesized derivatives. As the synthesized derivatives had extended conjugations, therefore the first hyperpolarizability (β_o) was calculated to investigate their potential as non-linear optical (NLO) materials and significant β_o values were found for the 2b and 2g derivatives.