Search

Distally substituted bis-1,3-diketone derivatives of calix[4]arene were synthesized, in which chelate groups are attached via a carbonyl carbon atom to the p-positions of phenolic fragments of a macrocycle fixed in 1,3-alternate isomeric form. 1,3-Diketone derivatives were obtained by acylation of magnesium enolate of a calix[4]arene ketone with 1-benzoylbenzotriazoles. In the synthesized compounds, 1,3-diketone groups are conjugated with the π-aromatic system of calix[4]arene. It was found by means of UV spectroscopy and NMR diffusion methods in combination with quantum chemical (DFT) calculations that a mononuclear complex with bis-chelate coordination of the lanthanide ion is predominantly formed in the solution. The formation of the complex leads to a decrease in the conjugation degree in the ligand. The most effective sensitization of Eu3+ luminescence, compared to the p-F- or p-CF3-phenyl-substituted complexes is observed for calix[4]arene complexes with H-phenyl-substituted 1,3-diketone groups. [ABSTRACT FROM AUTHOR]

The complex CuHL(NO3)2 · H2O, where HL = 3-acetylquinoxalin-2(1 H)-one was synthesized and studied. Elemental analysis, magnetochemistry, and ESR, electronic, and IR spectroscopy were used to show that this complex is a polymer with the copper ion having a distorted octahedral surrounding. Each ligand bidentately coordinates to one copper ion and monodentately coordinates to the second. [ABSTRACT FROM AUTHOR]

Distally substituted bis-1,3-diketone derivatives of calix[4]arene were synthesized, in which chelate groups are attached via a carbonyl carbon atom to the p-positions of phenolic fragments of a macrocycle fixed in 1,3-alternate isomeric form. 1,3-Diketone derivatives were obtained by acylation of magnesium enolate of a calix[4]arene ketone with 1-benzoylbenzotriazoles. In the synthesized compounds, 1,3-diketone groups are conjugated with the π-aromatic system of calix[4]arene. It was found by means of UV spectroscopy and NMR diffusion methods in combination with quantum chemical (DFT) calculations that a mononuclear complex with bis-chelate coordination of the lanthanide ion is predominantly formed in the solution. The formation of the complex leads to a decrease in the conjugation degree in the ligand. The most effective sensitization of Eu3+ luminescence, compared to the p-F- or p-CF3-phenyl-substituted complexes is observed for calix[4]arene complexes with H-phenyl-substituted 1,3-diketone groups. [ABSTRACT FROM AUTHOR]