Synthesis, Crystal Structure, and Photophysical Properties of Bromothiophene‐Functionalized BF2‐Curcuminoid as a Versatile Building Block

Abstract A novel bromothiophene‐functionalized BF 2 ‐curcuminoid (BTC‐BF 2 ) is synthesized by Knoevenagel condensation reaction. The structure of BTC‐BF 2 is determined by 1 H‐nuclear magnetic resonance ( 1 H NMR), 13 C‐nuclear magnetic resonance ( 13 C NMR), and high‐resolution mass spectrometry (HRMS). Moreover, a nearly coplanar single crystal structure is successfully obtained and form a mesh structure through intermolecular multiple C ─ H···F hydrogen bond interactions. As expected, as‐prepared BTC‐BF 2 exhibits solvent‐dependent photophysical properties in solvents with different polarity and an intense red solid‐state fluorescence. Density functional theory calculations further verify the relationships between its intrinsic electronic features and the photophysical properties. For its potential application aspect, BTC‐BF 2 shows a certain ability to generate singlet oxygen under irradiation with 530 nm green light. Moreover, BTC‐BF 2 can be utilized as versatile building block to construct novel far‐red or NIR BF 2 ‐curcuminoid complexes for widely biological applications.