Synthesis and luminescent properties of europium(III) and Terbium(III) complexes with acylated derivatives of 2-aminobenzoic acid

The optimal conditions for complex formation in solutions and synthesis of solid Eu(III) and Tb(III) complexes with acylated derivatives of aminobenzoic acid have been determined. The character and degree of effect of organic solvents, additional ligands, and surfactants on the complex photoluminescence intensity have been established.     

Synthesis,Antibacterial and Antifungal Activity of New 3-Aryl-5H-pyrrolo[1,2-a]imidazole and 5H-Imidazo[1,2-a]azepine Quaternary Salts

A series of novel 3-aryl-5H-pyrrolo[1,2-a]imidazole and 5H-imidazo[1,2-a]azepine quaternary salts were synthesized in 58–85% yields via the reaction of 3-aryl-6, 7-dihydro-5H-pyrrolo[1,2-a]imidazoles or 3-aryl-6,7,8,9-tetrahydro-5H-imidazo[1,2-a]azepines and various alkylating reagents. All compounds were characterized by ¹H NMR, ¹³C NMR, and LC-MS. The conducted screening studies of the in vitro antimicrobial activity of the new quaternary salts derivatives established that 15 of the 18 newly synthesized compounds show antibacterial and antifungal activity. Synthesized 3-(3,4-dichlorohenyl)-1-[(4-phenoxyphenylcarbamoyl)-methyl]-6,7-dihydro-5H-pyrrolo[1,2-a]imidazol-1-ium chloride 6c possessed a broad activity spectrum towards Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Cryptococcus neoformans, with a high hemolytic activity against human red blood cells and cytotoxicity against HEK-293. However, compound 6c is characterized by a low in vivo toxicity in mice (LD₅₀ > 2000 mg/kg).     

Spectral-kinetic characteristics of lutetium-containing tetrapyrroles

The spectral-kinetic characteristics of the triplet states of tetraphenylporphyrin and triphenylcorrole complexes with an aminopolycarboxylic acid (EDTA or DTPA) or its complex with lutetium as a substitute and the corrole complex with Ga(III) as the central atom have been studied. The transient absorption spectra of the complexes in the triplet excited state (effective maximum at 460–470 nm) and the rate constants of triplet quenching by oxygen at room temperature (2 × 10⁸–7 × 10⁸ L mol^?1 s^?1) have been measured. The quantum yields (0.44–0.55) and the molar absorption coefficients of the triplet state (log ?_T = 4.81–4.89) have been determined for some of the derivatives. The efficiency of population and deactivation kinetics of the triplet states are determined by the structure of the porphyrinoid, in particular by the central ion, and depends slightly on the presence of a heavy atom at the periphery of the molecule. Possible uses of the new compounds for designing various optical devices are discussed.     

β-Chlorocinnamonitriles in a New Synthesis of 3-Functionally Substituted 6-amino-1,2-Dihydropyridin-2-ones

β-Chlorocinnamonitriles react with methylene-active compounds containing N-substituted carboxamide group in DMSO solution in the presence of potassium hydroxide, forming 3-functionally substituted 1,2-dihydropyridin-2-ones.     

Luminescent sol–gel materials based on lanthanide aminopolycarboxylates (Ln = Nd, Eu, Tb, Yb)

Luminescent organic–inorganic hybrid materials containing immobilized lanthanide(III) complexes (Ln = Nd, Eu, Tb, Yb) with modified ethylenediaminetetraacetic and diethylenetriaminepentaacetic acid were synthesized by sol–gel method. Obtained hybrids exhibit 4f-luminescence in the visible (Eu(III) and Tb(III)) and IR-region (Nd(III) and Yb(III)). The influence of the hybrid matrix on the lanthanide luminescence was established and it was shown, that the location of resonance level of Eu(III) is optimal for efficient energy transfer from matrix, while in the case of Tb(III) energy transfer does not occur and Tb(III) is able to absorb energy only due to its own week f–f transitions. It was also established that the inorganic matrix leads to elimination of nonradiative energy losses and increase of 4f-luminescence lifetimes. Covalent binding of Ln(III) aminopolycarboxylates in the matrix allows to consider obtained materials as promising for creation of photo- and chemically-stable luminescent sensors.