Umetani, Shigeo published the artcileRole of the intramolecular hydrogen bond and ligand rigidity in the complexation of trifluoroacetylcycloalkanones with lanthanides: novel strategy for the design of organic ligands of high selectivity, Recommanded Product: 5-Methyl-2-phenyl-4-(2,2,2-trifluoroacetyl)-1H-pyrazol-3(2H)-one, the main research area is intramol hydrogen bond ligand rigidity complexation; trifluoroacetylcycloalkanone lanthanide complexation extraction.
Trifluoroacetylcyclopentanone (1), -cyclohexanone (2) and -cycloheptanone (3) were synthesized and the complexation with lanthanides (La3+, Pr3+, Eu3+, Ho3+ and Yb3+) was studied via the solvent extraction technique. The strength of the intramol. hydrogen bond depends on the distance between the two donating oxygens in the enol form estimated by semi-empirical MNDO/H and ab initio calculations The O-O distance for 1 is larger than those for 2 and 3 as predicted from their cyclic structures. The strength of the intramol. hydrogen bond increases in the order, 1<2≈3, which is also supported by 1H NMR and IR spectra. The acid dissociation constants (pKa) were measured by potentiometric titration in 30 dioxane-water. The pKa values increase in the order, 1<2≤3, reflecting the strength of the intramol. hydrogen bond. Lanthanides were readily extracted by 1 owing to its strong acidity. However, better separation for lanthanides was achieved with 2 and 3. The extractability and separability were discussed in terms of the ligand rigidity and the intramol. hydrogen bond originating from the distance between the two donating oxygens. Inorganica Chimica Acta published new progress about Complexation. 1691-93-6 belongs to class pyrazoles-derivatives, name is 5-Methyl-2-phenyl-4-(2,2,2-trifluoroacetyl)-1H-pyrazol-3(2H)-one, and the molecular formula is C12H9F3N2O2, Recommanded Product: 5-Methyl-2-phenyl-4-(2,2,2-trifluoroacetyl)-1H-pyrazol-3(2H)-one.
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics