On the Reactivity and Stability of Iodide–Nitride–Sulfide Clusters of Neodymium and Dysprosium

The thermal decomposition of cluster Nd₃I₅(S₂)(S₂N₂)(THF)10 (I) at 50–400°C affords a mixture of products among which tetrahydrofuran (THF), sulfur, diiodine, HI, H₂S, CS₂, S₃N₆, S₃N₅, MeI, thiophene, tetrahydrothiophene, diiodobutane, iodobutene, and NdI₃ are identified. The treatment of Ln₃I₅(S₂)(S₂N₂)(THF)₁₀ (Ln = Nd (I), Dy (II)) with phenanthroline (Phen) in THF at room temperature results in the partial substitution of ТНF to form new complexes Ln₃I₅(S₂)(S₂N₂)(THF)₄(Phen)₃. The dissolution of compound I in pyridine gives a pyridine (Py) complex Ln₃I₅(S₂)(S₂N₂)(THF)3(Py)₇. The dissolution of compounds I and II in acetonitrile at 20°C is accompanied by the fast rearrangement and fragmentation of the complexes to form LnI₃(MeCN)₆, [LnI(S₂)(MeCN)], and [LnI(S₂N₂)(MeCN)]. Complex I in THF does not react with white phosphorus, carbon monoxide, fullerene C₆₀, and chromium hexacarbonyl.     

Finite-element simulation of myocardial electrical excitation

Based on a single-domain model of myocardial conduction, isotropic and anisotropic finite element models of the myocardium are developed allowing excitation wave propagation to be studied. The Aliev-Panfilov phenomenological equations were used as the relations between the transmembrane current and the transmembrane potential. Interaction of an additional source of initial excitation with an excitation wave that passed and the spread of the excitation wave are studied using heart tomograms. A numerical solution is obtained using a splitting algorithm that allows the nonlinear boundary-value problem to be reduced to a sequence of simpler problems: ordinary differential equations and linear boundary-value problems in partial derivatives.     

Decacyclene Radical Anions Showing Strong Low‐energy Intramolecular Absorption and Magnetic Coupling of Spins in a Hexagonal Network

Two salts of the aromatic hydrocarbon decacyclene, {cryptand[2.2.2](Cs⁺)} (decacyclene^.?) ( 1 ) and {Bu₃MeP⁺}(decacyclene^.?) ( 2 ), were obtained. In both salts, decacyclene^.? radical anions formed channels occupied by cations. However, corrugated hexagonal decacyclene^.? layers could be outlined in the crystal structure of 1 with several side‐by‐side C???C approaches. The decacyclene^.? radical anions showed strong distortion in both salts, deviating from the C₃ symmetry owing to the repulsion of closely arranged hydrogen atoms and the Jahn‐Teller effect. Radical anions showed intense unusually low energy absorption in the IR‐range, with maxima at 4800 and 6000 cm^?1. According to the carculations, these bands can originate from the SOMO‐LUMO+1 and SOMO‐LUMO+2 transitions, respectively. Radical anions exhibited a S=1/2 spin state, with an effective magnetic moment of 1.72 μ_B at 300 K. The decacyclene^.? spin antiferromagnetically coupled with a Weiss temperature of ?11 K. Spin ordering was not observed down to 1.9 K owing to spin frustration in the hexagonal decacyclene^.? layers.     

Synthesis,structure and properties of N-aminosaccharin – A selective inhibitor of human carbonic anhydrase I

Previously unknown N-aminosaccharin was prepared in good yield via the one-step direct amination of saccharin sodium salt with hydroxylamine-O-mesitylenesulfonic acid (MSH) and its reactivity investigated. N-aminosaccharin and its derivatives were tested against hCA isoforms and the parent compound was identified to be a selective, low micromolar inhibitor (K_i = 8.8 μM) of hCA I. These findings provide a ligand-efficient starting point for the design of potent hCA I inhibitors – a promising drug target for retinal/cerebral edema treatment.     

Electrical and magnetic properties of nanodiamond and pyrocarbon composites

The electrical and magnetic properties of the nanodiamond composites comprising nanodiamond, pyrolytic carbon, and nanosized pores were studied. The composites are p-type semiconductors and their resistance decreases by 12 orders of magnitude as the pyrocarbon-to-diamond ratio γ increases from 0 to 80 wt %. Evidence for paramagnetic properties of the nanodiamond composites was obtained. The observed properties are explained by increased concentration of surface Tamm states. The paramagnetic properties are explained in terms of the electron spins localized on the nanodiamond surface in the composite.