Spectroscopic and electrochemical properties of 1,3-diketonatoboron derivatives

Abstract

A series of tetracoordinated boron complexes derived from various 1,j-diketones and bidentate ligands (oxalato, malonato, catecholato and difluoro) were prepared. Their absorption, fluorescence and phosphorescence spectra, a t ambient temperature and 77 K, and cyclic voltammmetry in acetonitrile were studied. The boron complexes exhibited high molar absorptivity and fluorescence intensities as compared with the parent diketones; the phenomena are in agreement with the lowest singlet excited state possessing the z, z,* configuration with a rigid chelate structure. The redox potential differences correlate linearly with the lowest singlet (E,) as well as the triplet (ET) excited state energy with slopes lower than unity. These linear correlations re-state that the electron exchange and Coulombic integral also vary proportionally to the potential differences. From these correlations, it is possible to determine E , and E , of those boron complexes that do not give fluorescence and phosphorescence.

Alkyl chain length effects on solid-state difluoroboron β-diketonate mechanochromic luminescence

“…In CH 2 Cl 2 solution, all the samples displayed absorption maxima at 399 AE 1 nm and exhibited high extinction coefficients, ranging from 50 100 to 66 200 (M À1 cm À1 ), similar to related boron diketonate dyes. 17,18,21 They showed emission maxima at 435 AE 1 nm (fwhm z 52 nm), high quantum yields (F F > 0.82), and similar fluorescence lifetimes ($2.0 ns) that were fitted to single exponential decay ( Fig. S1 and Table S1 †).…”

“…Further study of the relationship between molecular structure and mechanochromic behavior is merited. 1 Difluoroboron diketonates (BF 2 bdks) are classic dyes possessing impressive luminescent properties such as large extinction coefficients, [17][18][19] two-photon absorption cross-sections, 20 high fluorescence quantum yields, [17][18][19] and unusual room-temperature phosphorescence 21 (RTP) in solid-state media (e.g. polymers).…”

Two‐photon confocal imaging study: Cell uptake of two photon dyes‐labeled PAMAM dendrons in HeLa cells

“…For further purified the final compound was re-crystallized from acetone and hexane (1:3). Yield 82%, dark yellow solid, IR cm À1 : 1644 (C¼ ¼O, carboxyl), 1631 (C¼ ¼O, complexified with B), 3400 (AOH), 1…”

Two-photon excited fluorescence of BF2complexes of curcumin analogues: toward NIR-to-NIR fluorescent organic nanoparticles

“…Curcuminoid ligands have been used as labels in various imaging applications, [42][43][44] including those based on TPA. 45,46 Whereas there exists a variety of BF 2 complexes of molecules containing the acetylacetonate moiety showing unique optical and electronic properties, [47][48][49][50][51][52][53][54][55] TPA properties, 23,56,57 and potential for biological imaging, 58 reports on borondiuoride-containing curcuminoids are still scarce. 41,[59][60][61] Recently, related water-soluble derivatives have allowed bioimaging based on OPEF emission in the visible region.…”