Synthesis, characterization, and fluorescence properties of a novel symmetric di-nuclear b-diketonate ligand and its Eu3+ ternary chelate complex was written by Yang, Qing;Tang, Rui-ren. And the article was included in Xuzhou Gongcheng Xueyuan Xuebao, Ziran Kexueban in 2013.Safety of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate The following contents are mentioned in the article:
A novel β-diketonate ligand: 2,6-Bis(3-methyl-1-phenyl-5-pyrazolone-4-yl) pyridine was prepared and characterized by elemental anal. and 1 H NMR spectra. The result of the 1H NMR spectroscopy showed that the ligand L existed as an enol form isomer, which was consistent with the result of IR anal. In addition, its corresponding dinuclear Eu3+ complex using 1,10-phenanthroline as the second ligand was prepared and characterized by elemental anal., IR spectra, UV-Vis spectra, and 1 H NMR. The fluorescence spectra indicated that the ligand had excellent antenna effect to sensitize the Eu3+ ions, and the emission spectra was very sharp and narrow, which would be considered as a valuable material in organic electroluminescence materials. This study involved multiple reactions and reactants, such as Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate (cas: 17355-75-8Safety of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate).
Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate (cas: 17355-75-8) belongs to pyrazole derivatives. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C).Pyrazole used as a ligand to prepare organometallic compounds. The presence of both electronegative nitrogen atoms in the pyrazole ring reduces the electron density of the C3- and C5-positions leaving electron density of C4-position unaltered. Thus the C4-position is vulnerable to electrophilic attack. The C3 electrophilic-position may undergo deprotonation in the presence of a strong base leading to ring opening.Safety of Ethyl 1,5-diphenyl-1H-pyrazole-3-carboxylate
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics