Synthesis, structures and electrochemical and photophysical properties of anilido-benzoxazole boron difluoride (ABB) complexes. Issue 3 (20th November 2014)

• Record Type: Journal Article
• Authors: Meesala, Yedukondalu; Kavala, Veerababurao; Chang, Hao-Ching; Kuo, Ting-Shen; Yao, Ching-Fa; Lee, Way-Zen
• Is Part Of: Dalton transactions. Volume 44:Issue 3(2015)
• Page Start: 1120
• Page End: 1129
• Publication Date: 2014-11-20
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c4dt03052d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Four-ring-fused anilido-benzoxazole boron difluoride (ABB) dyes were synthesized, and exhibited very bright luminescence in solution ( Φ f = 0.45–0.96 in CH2 Cl2 ) and in the solid-state ( Φ f = 0.07–0.37). Abstract : A new series of four-ring-fused π-conjugated anilido-benzoxazole boron difluoride (ABB) dyes were synthesized by employing an unsymmetrical bidentate ligand under a mild reaction condition. X-ray structural analysis demonstrated that the four-ring-fused π-conjugated skeleton is nearly coplanar, and almost orthogonal to the side anilido phenyl group with dihedral angles of 74–86°. The synthesized complexes exhibit very bright luminescence in solution ( Φ f = 0.45–0.96 in CH2 Cl2 ) and in the solid-state ( Φ f = 0.07–0.37). These complexes show a larger Stokes shift (56–128 nm) than the well-known boron dipyrromethene dyes (8–12 nm, in most cases). The role of molecular packing patterns elucidated by the assistance of their X-ray crystal structures rationalizes the solid-state fluorescence. One of the tested compounds displayed aggregation induced emission (AIE). First-principle-based quantum-chemical studies were carried out on complexes1–6 . Time-dependent DFT (TD-DFT) calculations support the experimental results. The participation of the anilido phenyl moiety and the fluorine atoms was found to be negligible in the LUMO orbitals.