Triarylboron-functionalized 8-hydroxyquinolines and their aluminium(iii) complexes

Enhanced Photoluminescence of Crystalline Alq3 Micro-Rods Hybridized with Silver Nanowires

An enhancement of the local electric field at the metal/dielectric interface of hybrid materials due to the localized surface plasmon resonance (LSPR) phenomenon plays a particularly important role in versatile research fields resulting in a distinct modification of the electrical, as well as optical, properties of the hybrid material. In this paper, we succeeded in visually confirming the LSPR phenomenon in the crystalline tris(8-hydroxyquinoline) aluminum (Alq₃) micro-rod (MR) hybridized with silver (Ag) nanowire (NW) in the form of photoluminescence (PL) characteristics. Crystalline Alq₃ MRs were prepared by a self-assembly method under the mixed solution of protic and aprotic polar solvents, which could be easily applied to fabricate hybrid Alq₃/Ag structures. The hybridization between the crystalline Alq₃ MRs and Ag NWs was confirmed by the component analysis of the selected area electronic diffraction attached to high-resolution transmission electron microscope. Nanoscale and solid state PL experiments on the hybrid Alq₃/Ag structures using a lab-made laser confocal microscope exhibited a distinct enhancement of the PL intensity (approximately 26-fold), which also supported the LSPR effects between crystalline Alq₃ MRs and Ag NWs.

Synthesis and Photophysical Properties of a Series of Dimeric Indium Quinolinates

A novel class of quinolinol-based dimeric indium complexes (1-6) was synthesized and characterized using ¹H and ¹³C(¹H) NMR spectroscopy and elemental analysis. Compounds 1-6 exhibited typical low-energy absorption bands assignable to quinolinol-centered π-π* charge transfer (CT) transition. The emission spectra of 1-6 exhibited slight bathochromic shifts with increasing solvent polarity (p-xylene < tetrahydrofuran (THF) < dichloromethane (DCM)). The emission bands also showed a gradual redshift, with an increase in the electron-donating effect of substituents at the C5 position of the quinoline groups. The absolute emission quantum yields (Φ_PL) of compounds 1 (11.2% in THF and 17.2% in film) and 4 (17.8% in THF and 36.2% in film) with methyl substituents at the C5 position of the quinoline moieties were higher than those of the indium complexes with other substituents.

Propeller-Shaped Aluminum Complexes with an Azaperylene Core in the Ligands

Tris(8-hydroxyquinoline) aluminum(III) (Alq3) and its derivatives, characterized by a propeller-shaped three-dimensionally π-conjugated structure, have been intensively studied in the few past decades on account of their potential utility in optoelectronic applications. Reported herein are the synthesis and properties of π-extended Alq3 complexes that contain an azaperylene core in each ligand. Intramolecular palladium-catalyzed direct C–H arylations or base-promoted arylations were employed to prepare these large Alq3 analogues. A single-crystal X-ray diffraction analysis of one of the obtained Al complexes revealed a unique three-dimensional packing structure within the crystal, i.e., a honeycomb packing along the ab-plane and columnar π-stacks along the c-axis. An Alq3 analogue with azaperylene-dicarboximide ligands exhibited deep blue color in solution with an intense absorption band that extended to 780 nm (λmax = 634 nm; ε = 58,000 M−1 cm−1).

Triarylborane conjugated dicyanovinyl chromophores: intriguing optical properties and colorimetric anion discrimination

Three new triarylborane conjugated dicyanovinyl chromophores (Mes2B-π-donor-DCV); donor: N-methyldiphenylamine () and triphenylamine ( and [with two BMes2 substitutions]) of type A-D-A (acceptor-donor-acceptor) are reported. Compounds exhibit intense charge transfer (CT) absorption bands in the visible region. These absorption peaks are combination CT bands of the amine donor to both the BMes2 and DCV units. This inference was supported by theoretical studies. Compound shows weak fluorescence compared to and . The discrimination of fluoride and cyanide ions is essential in the case of triarylborane (TAB) based anion sensors as a similar response is given towards both the anions. Anion binding studies of , and showed that fluoride ions bind selectively to the boron centre and block the corresponding CT transition (donor to BMes2) leaving the other CT transition to be red shifted. On the other hand, cyanide ions bind with both the receptor sites and stop both the CT transition processes and hence a different colorimetric response was noted. The binding of F(-)/CN(-) induces colour changes in the visible region of the electronic spectra of and , which allows for the naked-eye detection of F(-) and CN(-) ions. The anion binding mechanisms are established using NMR titration experiments.

Colorimetric and fluorimetric detection of fluoride and cyanide ions using tri and tetra coordinated boron containing chromophores

Two organoboron based fluorophores pyrazabole 3 and BODIPY 4 have been designed and synthesized by the Pd-catalyzed Sonogashira cross-coupling reaction and successfully employed for fluoride and cyanide ion sensing.

Two novel indolo[3,2-b]carbazole derivatives containing dimesitylboron moieties: synthesis, photoluminescent and electroluminescent properties

The OLED devices fabricated using two novel indolo[3,2-b]carbazole derivatives containing dimesitylboron groups as electroluminescent materials show reasonably good performance.

Selective activation of lanthanide luminescence with triarylboron-functionalized ligands and visual fluoride indicators

Two triarylboron-functionalized carboxylate ligands have been found to be highly effective in selective activation of Tb(III) and Eu(III) emission and enable the use of the Tb(III) and Eu(III) complexes as highly effective luminescent indicators for F(-) and CN(-) in solution and on a solid substrate.