Diastereoselective intramolecular cyclization/Povarov reaction cascade for the one-pot synthesis of polycyclic quinolines.

The method for the synthesis of complex alkaloid-like aza-heterocycles has been developed through the Povarov reaction of in situ generated 2-oxoimidazolium cations. The reaction lead to the formation of 2 C-N, 2 C-C bonds and three stereocentres, and features excellent regio- and diastereoselectivity. Based on the controlled experiments and quantum chemistry data, the mechanism of the reaction cyclization was proposed and diastereoselectivity origins were rationalized. Additionally, a straightforward synthesis of hardly accessible 4,4'-bi(imidazol-2-one) derivatives has been achieved using the same methodology.

Temperature-sensitive emission of dialkylaminostyrylhetarene dyes and their incorporation into phospholipid aggregates: Applicability for thermal sensing and cellular uptake behavior.

A series of dialkylaminostyrylhetarene dyes constructed from electron-rich and electron-deficient moieties of various structures connected via vinylene π-bridges are introduced as temperature-sensitive luminophores. The temperature dependent emission of the dyes in the acidified dichloromethane solutions derives from temperature-induced shift of the equilibrium between neutral and protonated forms of the dyes. The heating-induced blue shift and intensification of emission of neutral form of the dyes make them a promising basis for development of nanoparticles exhibiting temperature-sensitivity in aqueous solutions at pH typical of biological liquids. Hydrophobicity-driven incorporation of the water insoluble dyes into L-α-phosphatidylcholine(PC)-based bilayers allows to obtain water dispersible dye-PC aggregates, and to follow their emission in the aqueous solutions. Structure of the dyes has strong impact on the efficacy of the dyes incorporation into the PC-based bilayers, temperature sensitivity of emission of the dye-PC aggregates and its reversibility under the heating/cooling cycles. This enables structural optimization of the dyes in order to obtain the dye-PC species demonstrating maximal temperature dependence and reversibility of their luminescence in aqueous solutions. The selected leader exhibits low cytotoxicity exemplified for M-HeLa and Chang Liver cell lines, while the efficient cell internalization of the dye, manifested in the staining of the cell cytoplasm, opens further opportunities for biosensing applications.

Chiral [16]-ane P4N2 macrocycles: stereoselective synthesis and unexpected intermolecular exchange of endocyclic fragments.

Chiral 1,9-diaza-3,7,11,15-tetraphosphacyclohexadecanes were stereoselectively synthesized as pure RPSPSPRP isomers via a one-pot Mannich-type condensation reaction of 1,3-bis(arylphosphino)propane, formaldehyde and optically active, as well as racemic, primary amines. An unprecedented intermolecular exchange of endocyclic amino fragments of 1,9-diaza-3,7,11,15-tetraphosphacyclohexadecanes was observed. The lability of the P-CH2-N fragment in macrocyclic aminomethylphosphines is the reason of the stereoisomerization, formation of products with medium-sized cycles as well as the exchange of endocyclic amino fragments. The mechanism of these transformations involving the formation of a methylenephosphonium intermediate and further intra- and intermolecular nucleophilic substitution is discussed.

The study of acute and chronic toxicity of the sodium-, calcium-, iron-polygalacturonate pharmacological substance in rabbits.

The purpose of this study is the assessment of the acute and chronic toxicity of pharmacological substance sodium, calcium, iron-polygalacturonate (PG Na,Ca,Fe) in rabbits as one of the stages of preclinical studies. We studied an acute and chronic oral toxicity of PG Na,Ca,Fe, which stimulates the process of hemopoiesis, in male and female rabbits of the "Chinchilla". According to the results of the study of acute toxicity of PG Na,Ca,Fe, treating with it the rabbits of both sexes in doses of 0.5-5 g/kg has no toxic effect (LD50 greater than 5 g/kg). The histostructure of studied organs of animals, treated with preparations in a dose of 5 g/kg, did not differ from that of the animals of the control group. This study allow to classify PG Na,Ca,Fe as a preparation of the 6th class with respect to harmless drugs. An estimate of the chronic toxicity of PG Na,Ca,Fe at administration of preparation in the form of boluses to rabbits in doses 0.025, 0.262 and 0.5 g/kg of the body weight demonstrated that the general condition and behavior of animals did not differ from the norm. The data of hematological and biochemical studies of blood serum and urine, electrocardiographic studies, the study of the mass coefficients of the internal organs of the experimental rabbits, treated with PG Na,Ca,Fe in the mentioned doses for 60 days, compared to those obtained in the 30-day post-observation period, did not show significant changes with respect to the control and intact group of rabbits.

The first representatives of tetranuclear gold(i) complexes of P,N-containing cyclophanes.

The first representatives of the tetranuclear gold(i) complexes of P,N-containing cyclophanes with two 1,5-diaza-3,7-diphosphacyclooctane rings incorporated into the macrocyclic core have been obtained. The complexation leads to a change in ligand conformations so that the diazadiphosphacyclooctane fragments of the complexes adopt twist-chair conformations, and two of the four gold(i) ions are located over and under the partially collapsed macrocyclic cavity. The complexes demonstrate moderate solid-state green emission.

Covalent self-assembly of the specific RSSR isomer of 14-membered tetrakisphosphine.

The first representative of the specific RSSR isomer of 14-membered tetrakisphosphine has been obtained instead of the RRRR/SSSS isomer predicted according to the empirical rule formulated recently. The geometry of the obtained 14-P4N2 is preorganized for the dicopper complex formation with the unique coordination mode in the row of P4N2 corands.

Oxygen reduction reaction catalyzed by nickel complexes based on thiophosphorylated calix[4]resorcinols and immobilized in the membrane electrode assembly of fuel cells.

The catalytic activity of the nickel complexes of thiophosphorylated calix[4]resorcinols for oxygen reduction in a polymer electrolyte membrane fuel cell (PEMFC) has been studied. The conformation of the macrocyclic ligand determines the morphology and catalytic properties of the resulting organometallic species.

Synthesis of novel pyridyl containing phospholanes and their polynuclear luminescent copper(i) complexes.

A novel type of cyclic P,N-ligands, pyridyl containing phospholanes, has been synthesized in a moderate yield by the reaction of primary phosphines with 1,4-dichlorobutane in a superbasic medium. A series of homo tetranuclear octahedral Cu4I4L2, dinuclear tetrahedral Cu2I2L3, and dinuclear "head-to-tail" Cu2I2L2 luminescent complexes with these ligands were obtained. All the compounds were characterized using a range of spectroscopic and computational techniques, and in the case of some Cu4I4L2 and Cu2I2L3 complexes, by single crystal X-ray diffraction. The structural diversity of the obtained complexes was reflected in their photophysical properties: phosphorescence spectra of the compounds display emission in broad spectral range of 471-615 nm. TD-DFT computations allow the assignment of a single emission band around 550 nm for Cu2I2L3 complexes and 471 nm for Cu2I2L2 complex to a vertical triplet-singlet transition from a metal-to-ligand and halide-to-ligand charge-transfer (3)(M + X)LCT excited state, whereas a second band at around 600 nm in the spectra of octahedral Cu4I4L2 complexes was assigned predominantly to Cu4I4 cluster-centered ((3)CC) excited state.

P,N-Containing cyclophanes with large helical hydrophobic cavities: prospective precursors for the design of a molecular reactor.

The highly effective self-assembly process between 2,4,6-tris(isopropyl)phenylphosphine or mesitylphosphine, formaldehyde and 1,4-bis(alpha-(4'-aminophenyl)isopropyl)benzene results in the formation of a novel type of heterocyclophane which is able to encapsulate organic molecules as well as being a potential ligand for transition metals inside the intramolecular cavity. Compounds of this type can be regarded as potential precursors for a new kind of molecular reactors.