Chun Keun Jang

Synthesis and optical properties of tetrapyrazino-porphyrazines containing camphorquinone group

2,3-dicyanopyrazine and metallophthalocyanines were synthesized with magnesium containing (±)camphorquinone substituent. 2,3-dicyanopyrazine was prepared by condensation reaction of diaminomaleonitrile (DAMN) with 1,7,7-trimethylbicyclo[2.2.1]heptane-2,3-dione (1). The tetrapyrazinoporphyrazine was characterized by a combination of UV-visible spectroscopy, fluorescence spectroscopy, infrared radiation, elemental analysis, MALDI-TOF-MS and 1H NMR spectroscopy.

Synthesis and spectral characterisation of dicyanopyrazine-related cyanoheterocycles

Four dicyanopyrazine-related cyanoheterocycles have been synthesised and characterised; they show different absorption maxima values and molar absorptivity in absorption spectra. HOMO and LUMO energy levels have been obtained by electrochemical measurements and DMol3 calculation and show little difference in HOMO values but big differences in LUMO values. Their UV-Vis absorbance and fluorescence spectra have been investigated in chloroform and toluene and their aggregation decreases as the concentration decreases in toluene.

Synthesis and optical properties of tetrapyrazinoporphyrazine containing phenylene dendron unit as a peripheral substituent

A dendritic shell can create a distinct micro-environment within its core. It also has the advantage of possessing unique photochemical, photophysical, electrochemical, and catalytic properties. Polyphenylene dendrons, which are characterized by their shape-persistent structures and out-of-plane twisted phenyl components, have previously been successfully attached to various functional groups. We have recently developed a convenient method for synthesizing a new type of porphyrazine that contains both flexible (linear) and more rigid (dendritic) groups. The synthesis of this completely aromatic and dendronic structure is unique in that it is based on a [2+4] Diels-Alder cycloaddition of tetraphenylcyclopentadienone to an ethynyl compound, followed by the elimination of carbon monoxide. In this study, tetrapyrazinoporphyrazinato metal and metal-free complexes were prepared by mixing 2,3-dicyano-5-polyphenylpyrazines with magnesium in n-butanol. The synthesized tetrapyrazinoporphyrazines were characterized by UV-visible spectroscopy, MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass) spectrometry, elemental analysis and 1H NMR spectroscopy.

2,3-Dicyanopyrazines Substituted Styryl Electron-Donor Group and Its Application for OLED Emitting Materials

2,3-Dicyanopyrazine were designed and synthesized via the Knoevenagel condensation of reaction 2,3-dicyano-5-methylpyrazines with 4-(diphenylamino)benzaldehyde. Their structure was characterized by 1H-NMR and FT-IR and elemental analysis. The electroluminescent (EL) performance of multi-layered organic light-emitting devices (OLEDs) fabricated with compound 3a as the emitting layer achieved a current efficiency of 1.57 cd/A with green region CIE coordinates of (0.37, 0.51) and 3b achieved a current efficiency of 0.238 cd/A with red region CIE coordinates of (0.54, 0.42).

Synthesis and characterization of novel blue azo‐dye derivatives containing acrylate group for dye‐based color filters

— Even though dyes have a fine resolution and good chromaticities, they are not widely used as coloring materials for color filters (CFs) due to their low thermal stability and chemical resistance. A series of azo-dye derivatives, which consist of two cross-linkable acrylate or methacrylate groups to improve thermal and chemical properties, have been synthesized and used to fabricate color filters. The spectral properties and chemical/thermal stabilities of the fabricated CFs were investigated by comparing dye-based CFs, without a complicated dispersion process, but with pigment-based CFs using dispersed pigment. Also, more properties including the development test and surface morphologies lithographic properties were studied. The synthesized azo dyes were characterized by elemental analysis, UV-visible spectra, IR, mass, and 1H-NMR spectra.

Synthesis and optical properties of tetrapyrazinoporphyrazines containing asymmetrical alkyl chains and t-butylphenyl groups

Tetrapyrazinoporphyrazine magnesium complexes with four long alkyl groups and four 4-tert-butyl phenyl groups at the peripheral positions were synthesized from 2,3-dicyano-5-(4-tert-butylphenyl)-6-alkyl pyrazine derivatives using freshly prepared solutions of magnesium butoxide in n-butanol. The corresponding metal-free derivatives were obtained through treatment with p-toluenesulfonic acid. The resulting chromophores contained alkyl chains substituted at their peripheries and showed good solubility in organic solvents. The fluorescence of the tetrapyrazinoporphyrazine magnesium complexes was greatly influenced by the intermolecular aggregation. Q band spectra of the porphyrazine magnesium complexes in DMF exhibited the characteristic patterns of the monomeric species, with fluorescence maxima at 653–658 nm. These new compounds were characterized using UV-visible spectroscopy, MALDI-TOF-MS and 1H NMR spectroscopy.

Synthesis and Characterization of Novel Tetrapyrazinoporphyrazine Derivatives Containing Morpholine and tert-Butyl Group

Tetrapyrazinoporphyrazine magnesium complexes were synthesized from 2,3-dicyano-5-(4-alkylphenyl)-6-(4-morpholinophenyl)pyrazine derivatives using freshly prepared solutions of magnesium butoxide in n-butanol. The corresponding metal-free derivatives were obtained by treatment with p-toluenesulfonic acid. Copper complexes were successfully synthesized using excess cuprous chloride and DBU (1,8-diazabicyclo[5,4,0]-7-undecene) as a catalyst in o-dichlorobenzene under reflux. The tetrapyrazinoporphyrazines were characterized by elemental analysis, UV-visible spectra, IR, MALDI-TOF Ms and 1H-NMR spectra.

Synthesis of perialkynylated tetrapyrazinoporphyrazines and its optical properties

Some phthalocyanines soluble in organic solvents have been developed by peripheral introduction of substituent groups. We report a new method for preparation of the polyphenyl-substituted dicyanopyrazines based on the [2 + 4] Diels-Alder cycloaddition of the tetraphenylcyclopentadienone to an ethynyl compound. The synthesised tetrapyrazinoporphyrazinato metal complexes were characterised by UV-visible spectroscopy, MALDI-TOF-Ms (matrix-assisted laser desorption ionisation time-of-flight mass) spectroscopy, and 1H NMR spectroscopy.

Synthesis and spectral properties of tetraquinoxalino-porphyrazines containing benzocrown-ether group

The synthesis and spectral properties of the metal-free and the Mg complex derivatives of crown-substituted tetraquinoxalinoporphyrazine are described. Porphyrazine 4 and 5 have satisfactory solubility in chlorinated hydrocarbons, THF and toluene, but are practically insoluble in alcohols. Porphyrazine 5 generally did not show aggregation in CHCl3 but aggregate in DMF.

Red-emitting materials derived from 2,3-dicyanopyrazine for organic light emitting devices

Styryl-substituted derivatives of 2,3-dicyanopyrazine were designed and synthesised by the Knoevenagel condensation of 2,3-dicyano-5-methylpyrazines with 4-(diphenylamino)benzaldehyde for use as red-emitting fluorescent dyes in organic light-emitting devices. Structural analysis of the red-emitting styryl fluorescent dyes was carried out using 1H NMR, FT-IR, and elemental analysis. The electroluminescent performance of multi-layered organic light-emitting devices fabricated with the triphenylamine-substituted dicyanopyrazine compound as the emitting layer achieved a current efficiency of 1.57 cd A-1 in the green region with CIE coordinates of (0.37, 0.51). However, the green emission (525 nm) observed from the tris-(8-hydroxyquinolinato)aluminum(III) (Alq3) electron-transport layer indicated the action of a recombination phenomenon between the emitting layer and the Alq3 electron-transport layer. The device fabricated with the tert-butylphenyl-substituted compound achieved a current efficiency of 0.238 cd A-1 in the red region with CIE coordinates of (0.54, 0.42) and showed no recombination phenomenon.