Thiazole Boron Difluoride Dyes with Large Stokes Shift, Solid State Emission and Room-Temperature Phosphorescence

The small Stokes shift and weak emission in the solid state are two main shortcomings associated with the boron-dipyrromethene (BODIPY) family of dyes. This study presents the design, synthesis and luminescent properties of boron difluoro complexes of 2-aryl-5-alkylamino-4-alkylaminocarbonylthiazoles. These dyes display Stokes shifts (Δλ, 77-101 nm) with quantum yields (ϕ_FL ) up to 64.9 and 34.7 % in toluene solution and in solid state, respectively. Some of these compounds exhibit dual fluorescence and room-temperature phosphorescence (RTP) emission properties with modulable phosphorescence quantum yields (ϕ_PL ) and lifetime (τ_p up to 251 μs). The presence of intramolecular H-bonds and negligible π-π stacking revealed by X-ray crystal structure might account for the observed large Stokes shift and significant solid-state emission of these fluorophores, while the enhanced spin-orbit coupling (SOC) of iodine and the self-assembly driven by halogen bonding, π-π and C-H^… π interactions could be responsible for the observed RTP of iodine containing phosphors.

Blue highly fluorescent boron difluoride complexes based on phthalazine–pyridine

Synthesis and characterization of three blue fluorescent phthalazine–pyridine boron complexes with quantum yields up to 79%.

Synthesis, spectroscopic and catalytic properties of some new boron hybrid molecule derivatives by BF2 and BPh2 chelation

A new series of Schiff base ligands (L1-L3) and their corresponding fluorine/phenyl boron hybrid complexes [LnBF2] and [LnBPh2] (n=1, 2 or 3) have been synthesized and well characterized by both analytical and spectroscopic methods. The Schiff base ligands and their corresponding fluorine/phenyl boron hybrid complexes have been characterized by NMR ((1)H, (13)C and (19)F), FT-IR, UV-Vis, LC-MS, and fluorescence spectroscopy as well as melting point and elemental analysis. The fluorescence efficiencies of phenyl chelate complexes are greatly red-shifted compared to those of the fluorine chelate analogs based on the same ligands, presumably due to the large steric hindrance and hard π→π(∗) transition of the diphenyl boron chelation, which can effectively prevent molecular aggregation. The boron hybrid complexes were applied to the transfer hydrogenation of acetophenone derivatives to 1-phenylethanol derivatives in the presence of 2-propanol as the hydrogen source. The catalytic studies showed that boron hybrid complexes are good catalytic precursors for transfer hydrogenation of aromatic ketones in 0.1M iso-PrOH solution. Also, we have found that both steric and electronic factors have a significant impact on the catalytic properties of this class of molecules.

Efficient electrochemiluminescence of a readily accessible boron difluoride formazanate dye

Systematic studies of the electrochemiluminescence (ECL) of a boron difluoride formazanate dye reveal three distinct, voltage-dependent mechanisms of light emission.

Synthesis, structures and electrochemical and photophysical properties of anilido-benzoxazole boron difluoride (ABB) complexes

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 CH₂Cl₂) and in the solid-state (Φ_f = 0.07–0.37).

[N-((E)-2-{[2-(Dimethyl-amino)-eth-yl]imino-meth-yl}phen-yl)-N-(2,6-dimethyl-phen-yl)anilinido-κN,N',N'']ethyl-zinc

The title eth­yl–zinc complex, [Zn(C₂H₅)(C₁₉H₂₄N₃)], bears a tridentate anilinide–aldimine ligand and features one long Zn—N(amine) bond length, attributable to the crowded environment of the coordinated metal, arising from the dimethyl­phenyl group. The Zn^II ion adopts a distorted tetra­hedral geometry, the dihedral angle between the two benzene rings being 86.05 (16)°.

Tuning the intensity of metal-enhanced fluorescence by engineering silver nanoparticle arrays

It is demonstrated that silver nanoparticle (SNP) arrays fabricated by combining nanoimprint lithography and electrochemical deposition methods can be used as substrates for metal-enhanced fluorescence, which is widely used in optics, sensitive detection, and bioimaging. The method presented here is simple and efficient at controlling the nanoparticle density and interparticle distance within one array. Furthermore, it is found that the fluorescence intensity can be tuned by engineering the feature size of the SNP arrays. This is due to the different coupling efficiency between the emission of the fluorophores and surface plasmon resonance band of the metallic nanostructures.

Electroluminescent Properties of a Schiff-Base Aluminum Complex in Single Layer Polymer Light-Emitting Diodes

The Schiff-base ligand aluminum complex, [AlLMe2] [L = ortho-C6H4(NC6H3Me2-2,6)(CH=NC6H3Me2-2,6)], has been synthesised and characterised; its electroluminescent properties are reported. Electroluminescent devices were fabricated by doping [AlLMe2] in a polymer host of poly (vinylcarbazole) (PVK) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) using a simple solution spin-coating technique. The single-layer polymer organic light-emitter devices exhibited green emission, showed maximum current efficiency of 1.4 cd/A and maximum luminance of near 1000 cd/m2.