Multi-state emission properties and the inherent mechanism of D–A–D type asymmetric organic boron complexes

Abstract

Fluorescence emission properties in the single molecule, crystalline and amorphous state are key factors determining the application fields and scope of luminogens.

Aggregation-induced emission enhancement (AIEE)-active boron-difluoride dyes with reversible mechanochromic fluorescence

“…13 Fluorescent dyes with AIEE properties have many advantages for practical application in the elds of analytical detection, uorescence imaging and luminescent devices. For AIEE-active boron-diuoride dyes, non-pyrrolebased ligands with asymmetrical structures were normally adopted, such as b-diketone or N-substituted b-diketone derivatives, [14][15][16][17][18] b-iminoenolate derivatives [19][20][21][22][23][24][25][26][27] and others. [28][29][30][31][32][33][34][35] All these dyes bear rotatable bulky aromatic groups, which promotes the non-irradiative decay in dilute solutions.…”

Effect of methyl at the 1-phenyl of tetraaryl substituted imidazole boron difluoride complexes: synthesis, characterization, photophysical and electrochemical studies

“…All 1 H and 13 C NMR spectra were referenced internally to solvent signals. 11 B NMR spectra were referenced externally to BF 3 · Et 2 O in CDCl 3 (δ = 0 ppm), and 19 F NMR spectra were referenced to α,α,α-trifluorotoluene (0.05% in CDCl 3 ; δ = -63.73 ppm). All NMR spectra were recorded at ambient temperature.…”

“…The B-O and B-N bond lengths are amenable to those other literature reported boron complexes. 7,10,32,33 N,O Chelation favors the six-membered boron ring with a twisted conformation. In such a twist the coplanarity is lost between the imidazole and phenolate rings.…”

“…Tetra-coordinated boron compounds as emissive dyes have gained research interest due to their potential applications in sensing, imaging, and organic light emitting diodes. [1][2][3][4][5][6][7][8][9][10][11][12][13] Much effort has been devoted to the development of N,N-coordinated boron dipyrromethene (BODIPY) derivatives because of their excellent photophysical properties and diverse chemistry. 14,15 However, very poor solid-state emission and small Stokes shift and low photostability limit its potential applications.…”

Osmaindenes: Synthesis and Reversible Mechanochromism Characteristics

“…It is well known that a change in fluorescence color is often accompanied by a change in the packing pattern. [31][32][33] Therefore, we analyzed the crystal packing arrangements of complexes 2, 3, and 5 and the possible interactions between these molecules in an effort to explain the reversible mechanochromism properties of 1-6 from a molecular perspective. Figures 7A, B, and C show crystal packing diagrams of complexes 2, 3, and 5, respectively.…”