Fluorescent boron complexes based on newN,O-chelates as promising candidates for flow cytometry

Abstract

This study presents the synthesis and optical properties of a new class of bright green-yellow fluorescent dyes with potential applications in bioimaging. A facile synthetic route via the chelation of aryl(hetaryl)aminoacryloylthiophene scaffolds with a BF2 fragment is presented. The photophysical properties of the dyes are attributed to the nature and position of electron-donating and electron-withdrawing substituents. Upon coordination to a BF2 fragment, characteristic emission was observed, with λem ranging from 503 to 543 nm and quantum yields of 0.14-0.42. Compared with parent aryl(hetaryl)aminoacryloylthiophenes, a significant red shift in absorption (up to 480 nm in solution) and emission (up to 543 nm in solution and 610 nm in the solid state) and high chemical stability and photostability were observed. The electron-accepting character of the substituents on the terminal aromatic ring or replacing this fragment with pyridine or pyrazine moieties resulted in increased quantum yields. To gain insight into the electronic structures and optical properties, quantum mechanical calculations were performed. The results of (TD-)DFT calculations supported the structural and spectroscopic data and showed the features of electronic distribution in the frontier molecular orbitals and active electrophilic and nucleophilic sites in the compounds investigated. Synthesized BF2 complexes are promising dyes for cell imaging and flow cytometry owing to their ready penetration and accumulation in cells.

Tannic Acid as a Natural Ferroptosis Inhibitor: Mechanisms and Beneficial Role of 3’‐O‐Galloylation

“…As shown in Figure 7A, Fer‐1 substantially alters the UV spectra after mixing with the ferrous solution, implying the occurrence of ferrous complexation. However, no evident bathochromic shift is observed, suggesting that the ferrous ion insertion does not expand the conjugated aromatic system, and the energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital does not decrease significantly [33,34] . As Fer‐1 contains a single aromatic ring, ferrous ion insertion does not afford any color.…”

A highly fluorescent tri-nuclear boron complex with large Stokes shifts based on tripodal Schiff base: synthesis and photophysical properties

“…Quinine sulfate ( F = 0.54 in 0.1 M H 2 SO 4 ) was employed as standard. 28 The fluorescence quantum yields of 3 were determined in distinct organic solvents at room temperature and the obtained data were summarized in Table 1.…”

The synthesis, characterization and fluorescent properties of a new Schiff base-boron complex

“…A and A Std are the absorbances of the sample and standard corresponding to excitation wavelengths, and n 2 and n 2 Std are refer to refractive indices of solvents (n acetone : 1.36, n acetonitrile : 1.34, n chloroform : 1.44, n DCM : 1.42, n DMF : 1.43, n DMSO : 1.48, n THF : 1.41) in prepared solutions for the sample and standard, respectively. Quinine sulfate (Φ F = 0.54 in 0.1 M H 2 SO 4 ) was utilized as standard [23]. The absorbances of the solutions were adjusted to be between 0.04 and 0.05.…”