Synthesis and Spectroscopic Properties of Synthetic Chemical Polymerized 8-Hydroxyquinoline and Its Cu Complex 1 Yu Haihu, Chen Xiaoyu, Hu Weida, Yang Enyu, Li Honghui, Li Xiaoyu (Center for Optical Fiber Sensing Technology, Wuhan University of Technology, Wuhan, Hubei Province, China) It has also been found that the Cu (I) complexes of macromolecularized 8-hydroxyquinoline have strong fluorescence emission characteristics and good film forming properties. : 8-Hydroxyquinoline; Macromolecule; Cu(I) complexes; UV-Vis absorption spectroscopy; Fluorescence spectroscopy Organic small molecule metal complexes have been extensively studied in the field of electroluminescence, of which 8-hydroxy is of particular interest. Quinoline (abbreviated as 8Q) metal complexes. Tang et al. developed a green light-emitting electroluminescent device using 8-hydroxyquinoline aluminum (Alq3) with a luminous efficiency of 1.5 lm/W at a bias voltage of 5.5 V and a lifetime of approximately 100 h during continuous operation. Magnetic stirring in a water bath resulted in the precipitation of a yellow precipitate (h~3h). Filter, the filter cake washed with acetone three times, 40C ~ 50C vacuum drying to get 5C1CH28Q 11.63g triethylamine 13mL in a conical flask with 25mL of toluene dissolved 5g at about 65C magnetic stirring for about 30h, cooled to room temperature and filtered, the filtrate steamed Dry the solvent, the residue was washed with petroleum ether in chloroform multiple times, separated and evaporated to remove impurities. P20008Q. IR: = 3510 indicates the synthesis product is P2000-8Q. Preparation 0g dissolved in 10mL THF mixed brown precipitate, filtered, filtered The cake was washed with THF and dried in vacuo at 50C to give 2000-attribution to the hydroxyquinoline group, which was red-shifted relative to P2000-8Q. This was due to the coordination of the nitrogen atom with Cu and the decrease of the C=N bond force constant. In addition, the vibration peak 3510 (uH) (mh and 949 (0-1)+1 disappears because of the formation of CuO coordination bond, which results from the disappearance of 0H. u = 1 is attributed to the polymer ef-famine ED-2000 Compared with P20008Q, blue shift occurs because P2000-8Q forms Cu complex and the steric hindrance effect of the molecule increases. IR spectroscopy results show that the synthesized product is P20008QCu. A film is formed on the substrate, the substrate is quartz glass, and the substrate is Sonicate for 20 min in sonication, then sonicate in ethanol for 10 min, then sonicate in water for 10 min, rinse with ultrapure water, and dry for multiple times. Use the UV-vis absorption and fluorescence spectra of solutions and films.2 Results and discussion 2.1 P2000-8Q and P20008QCu water-soluble and film-forming P20008Q aqueous solution is brown-yellow, P2000-8QCu aqueous solution is yellow-green, their solubility in water is related to the pH of the solution, in which the solubility of P2000-8Q with alkaline With increasing and increasing, P2000-8QCu increases with the increase of acidity.Under alkaline conditions, the aqueous solution of P20008QCu is not stable, when the pH value exceeds 7, Cu(0H) precipitates out of the solution, indicating that under alkaline conditions P20008QCu is less stable than Cu(OH)2. P20008Q and P2000-8QCu have hydroxyl groups and can be prepared by sol-gel method, spin coating, etc. Each absorption peak also corresponds to the å…€5X transition in organic molecules. It can be seen that the absorption intensity of the P2000-8Q thin film is low, and there is an obvious absorption shoulder on the absorption curve of the P2000-8Q solution and the thin film, which corresponds to the transition between the electronic energy levels nn, which is a forbidden transition. , is due to molecules The absorption of the lone pair of electrons in the heteroatom substituted group to the antibonding orbital.The absorption intensity of the P20008QCu film is higher than that of the P2000-8Q film.The absorption peak of the film is slightly red-shifted. See the absorption curve of the P20008QCU film. Absorption bands that do not reach the MLCT (Meal Ligand Charge Transfer) transition show that this transition often occurs between the central metal ion of the complex and the ligand, that is, the transition of the electron from the electron-rich side to the electron-side transition in the metal complex P2000- 8QCu is forbidden.
It indicates that the absorption peak of P20008QCu film slightly shifts with the increase of pH value. From the absorption curve, it can also be seen that the absorption curves in the film and the solution correspond to each other, and no new absorption peak appears in the absorption spectrum, but the peak width and the peak position slightly change. This may be due to the multiplicity of vibrational energy levels in the two polyatomic molecules and the slight change in their aggregation in the solution and in the film.
The fluorescence spectrum of the liquid is as shown. After light energy absorption occurs in the P2000-8Q and P2000-8QCu solutions, the electrons transition from the ground state to the excited state, and after the higher excited state molecules are reduced in vibration to the lowest vibrational level of the excited singlet state, they are in the form of emitted light quanta. The transitions between n and intervening occur back to the ground state, and the wavelength of radiation corresponds to the absorption position. The emission peak of the synthesized P20008Q stock solution was at 553 nm, and the emission peak of the P20008Q aqueous solution dissolved in ultrapure water was blue shifted by about 50 nm from the original solution, indicating that the aggregation state of the molecule caused a great change in the position and intensity of the emission peak. The P2000-8Q solution emits fluorescence only at a certain range of pH values, and the fluorescence is weak under strong acid or alkali conditions. The P20008QCu solution is unstable under alkaline conditions and has strong fluorescence only under acidic conditions. The fluorescence emission band is around 470 nm, and the position and peak shape of the emission peak are not changed very much. It can be seen that the emission curves of P20008Q and P20008QCu have broad emission bands, but the emission peaks of the complexes show a blue shift and the absorption intensity is also strong. It was shown that the fluorescent effect of the ligand P2000-8Q was weaker, and complexes with Cu2+ formed a complex with a cyclic structure, which increased the rigidity of the molecule and had a coplanar character, thereby greatly reducing the probability of no radiative transition and resulting in a radiative transition probability. improve.
Comparing the fluorescence spectra of the liquid and the P2000-8QCu film, it can be found that there is a big difference between the two. For P2000-8QCu solution, the emission peak gradually shifts to red with the increase of the concentration, but the peak shape is basically not due to the different aggregation state of the molecule.
The results of film formation and spectral characteristics of P20008Q and P200-8QCu show that P200-8QCu has good film-forming and photoluminescence properties and can be used as an electronic luminescent material for the development of organic electroluminescent devices.
3 Conclusions But the solubility is related to the pH, P20008QCu is not stable under alkaline conditions. The light absorption of the P20008Q and P2000-8QCu aqueous solutions occurs in the near-ultraviolet region, and the absorption peak corresponds to the electronic energy level transition. The aqueous solutions of P20008Q and P2000-8QCu can emit fluorescence under certain wavelength excitation, but the fluorescence emission of P2000-8QCu aqueous solution is obviously stronger than that of P2000-8Q and its aqueous solution. P20008Q is creamy and hard to form a solid film; P2000-8QCu has good film forming properties, and the film is a yellow uniform and transparent solid film and can be used as an electron type electroluminescent material. According to this experimental method, a macromolecular 8-hydroxyquinoline complex other than copper can also be prepared.
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