POROUS METAL-ORGANIC FRAMEWORKS: FROM SYNTHESIS TO FUNCTIONAL PROPERTIES

Lying on the crossing of fundamental inorganic/organic chemistry and development of novel materials, metal-organic frameworks (MOFs) have become one of the most attractive research fields during the past two decades. MOFs can be self-assembled from a large number of metal ions/clusters with organic linkers and can be regarded as multifunctional materials due to a wide range of important properties. MOFs often combine properties caused by specific framework architecture, e.g. permanent porosity, selective gas sorption and separation, and chemical stability, with those ones related to the properties of inorganic building blocks, e.g. luminescence and magnetism. Here we describe our recent results on synthesis, structural characterization and investigation of multifunctional materials based on porous coordination polymers.This work was supported by the Russian Foundation for Basic Research (Grant No. 18-29-04001) and the Russian Science Foundation (Grant No. 19-73-20087)

Peculiarities of syntropic functional disorders of the digestive system against the ground of connective tissue dysplasia

A considerable occurrence of functional gastrointestinal disorders (FGID) in childhood, their frequent combination between themselves, the risk of transformation into organic pathology together with high collagen content in the digestive organs require investigation of pathophysiological relations of the pathology with collagen dysfunction. Objective of the study is to investigate the role of collagen disorders in FGID pathophysiology and assess their effect on clinical development of irritable bowel syndrome. 63 children suffering from FGID have been examined. Irritable bowel syndrome was diagnosed as a leading functional disorder of all the children examined. Syntropic functional biliary disorders were found in (38,46±6,13) % patients. By the results of molecular-genetic examination genetic polymorphism of COL3A1 rs1800255 with prevailing the genotype G/А – 47,62 % (95 % CІ 35,04 – 60,2) was determined, that was most reliably found (р = 0,008) in children with syntropic functional biliary disorders and was associated with a wide range of comorbid pathology (р = 0,002) and pronounced dysplastic signs (р = 0,034)

Understanding hysteresis in carbon dioxide sorption in porous metal-organic frameworks

Two new isostructural microporous coordination frameworks [Mn3(Hpdc)2­(pdc)2] (1) and [Mg3(Hpdc)2­(pdc)2] (2) (pdc2– = pyridine-2,4-dicarboxylate) showing primitive cubic (pcu) topology have been prepared and characterized. The pore aperture of the channels is too narrow for the efficient adsorption of N2; however, both compounds demonstrate substantially higher uptake of CO2 (119.9 mL·g–1 for 1 and 102.5 mL·g–1 for 2 at 195 K, 1 bar). Despite of their structural similarities, 2 shows a typical reversible type I isotherm for adsorption/desorption of CO2, while 1 features a two-step adsorption process with a very broad hysteresis between the adsorption and desorption curves. This behavior can be explained by a combination of density functional theory calculations, sorption, and X-ray diffraction analysis and gives insights into the further development of new sorbents showing adsorption/desorption hysteresis

Effective Field and the Bloch-Siegert Shift at Bihromatic Excitation of Multiphoton EPR

The dynamics of multiphoton transitions in a two-level spin system excited by transverse microwave and longitudinal RF fields with the frequencies w_{mw} and w_{rf}, respectively, is analyzed. The effective time-independent Hamiltonian describing the "dressed" spin states of the "spin + bichromatic field" system is obtained by using the Krylov-Bogoliubov-Mitropolsky averaging method. The direct detection of the time behavior of the spin system by the method of nonstationary nutations makes it possible to identify the multiphoton transitions for resonances w_{0} = w_{mw} + rw_{rf} (w_{0} is the central frequency of the EPR line, r = 1, 2), to measure the amplitudes of the effective fields of these transitions, and to determine the features generated by the inhomogeneous broadening of the EPR line. It is shown that the Bloch-Siegert shifts for multiphoton resonances at the inhomogeneous broadening of spectral lines reduce only the nutation amplitude but do not change their frequencies.Comment: 6 pages, 5 figure

Polymeric hybrid iodoplumbates and iodobismuthates containing mono- and bisalkylated derivatives of 1,2-bis(4-pyridyl)ethylene: Structural and optical features

© 2017 Elsevier B.V.Reactions of PbI2 with N-alkylated derivatives of 1,2-bis(4-pyridyl)ethylene (bpen) MeBpenI and Me2BpenI2 result in 1D-polymeric complexes [{Pb(MeBpen)I3}] (1) and (Me2bpen)[{PbI3}]2 (2). For both compounds, band gap values were determinated experimentally; 1 demonstrates weak red luminescence. Binuclear hybrid iodobismuthate [Bi2(MeBpen)2I8] (3) was obtained by the similar scheme using BiI3 instead of PbI2

Search for Branons at LEP

We search, in the context of extra-dimension scenarios, for the possible existence of brane fluctuations, called branons. Events with a single photon or a single Z-boson and missing energy and momentum collected with the L3 detector in e^+ e^- collisions at centre-of-mass energies sqrt{s}=189-209$ GeV are analysed. No excess over the Standard Model expectations is found and a lower limit at 95% confidence level of 103 GeV is derived for the mass of branons, for a scenario with small brane tensions. Alternatively, under the assumption of a light branon, brane tensions below 180 GeV are excluded