Nature and strength of weak intermolecular interactions with metal atoms in crystals of square-planar nickel(<Emphasis Type="SmallCaps">ii</Emphasis>) complexes

The results of geometric analysis of 588 crystal structures of square-planar nickel complexes containing short intermolecular Ni…X contacts (X is a non-metal atom) are reported. The frequency of occurrence of Ni…X interactions of a particular type was evaluated depending on the nature of the X atom and geometric characteristics. The promolecular functions RDG and sign(λ₂)?ρ(r) were used to analyze the character of Ni…X interactions in attractive/repulsive terms. The relative strength of these interactions was determined as the function of the nature of the X atom and the direction of charge transfer.     

Primary photophysical and photochemical processes for Pt(SCN)<Subscript>6</Subscript><Superscript>2–</Superscript> complex

Photosolvation of a Pt^IV hexathiocyanate complex Pt(SCN)₆ ^2– in water and ethanol was studied by steady-state photolysis, nanosecond laser flash photolysis, and ultrafast kinetic spectroscopy. Complexes Pt(SCN)₅(H₂O)^– and Pt(SCN)₅(C₂H₅OH)^– were found to be the only reaction products. The quantum yields of photosolvation are independent of the excitation wavelength, being equal to 0.25 and 0.5 for the solutions of the complex in water and ethanol, respectively. Photosolvation proceeds by the mechanism of heterolytic metal—ligand bond dissociation without involvement of redox processes. The characteristic time of formation of the end products for both solvents is about 10 ps. Three successive intermediates detected on the picosecond time scale were interpreted as Pt^IV complexes. The nature of the intermediates and possible mechanisms of photosolvation are discussed.     

Phototransformations of azetidine radical cations stabilized in freonic matrices

It has been established that transformations of azetidine radical cations observed in freonic matrices under the action of light with λ = 436 nm (T = 77 K) are associated with C-N bond cleavage which corresponds to the cyclic form yielding a mixture of open distonic C-centered radical cations of the following structure: ·CH₂CH₂CH=NH ₂ ⁺      

Coinage metal complexes of 2-diphenylphosphino-3-methylindole

Coordination of P,N indolyl-phosphine ligands to Au(I), Ag(I) and Cu(I) metal ions under weakly basic conditions results in easy deprotonation of the indolyl N-H function and effective formation of a family of homo- and heterobimetallic complexes MM'(PPh(2)C(9)H(7)N)(2) (M = M' = Au (2), Ag (5); M = Au, M' = Cu (3), Ag (4)). The latter (4) exists as an inseparable mixture of four different complexes, which are in equilibrium driven by slow dynamics. The reaction of silver(I) and copper(I) ions with PPh(2)(C(9)H(8)N) affords a rare tetranuclear Z-shaped cluster Ag(2)Cu(2)(PPh(2)C(9)H(7)N)(4) (6), which exhibits red luminescence in solid state (650 nm) and a weak dual emission in solution with the main component in the near-IR region (746 nm).     

Finite-Dimensional Sturm–Liouville Vessels and Their Tau Functions

We introduce a theory of a class of finite-dimensional vessels, a concept originating from the pioneering work of Livšic (Soobshch Akad Nauk Gruzin SSSR 91(2):281–284, 1978). Our work may be considered as a first step toward analyzing and constructing Lax Phillips scattering theory for Sturm–Liouville differentiable equations on the half axis (0,∞) with singularity at 0. We also develop a rich and interesting theory of vessels with deep connections to the notion of the τ function, arising in non linear differential equations (LDE), and to the Galois differential theory for LDEs.     

(3 + 3)-Cyclodimerization of donor-acceptor cyclopropanes. Three routes to six-membered rings

The ability of donor-acceptor cyclopropanes to (3 + 3)-cyclodimerize is disclosed. It has been found that Lewis acid-induced transformations of 2-(hetero)arylcyclopropane-1,1-dicarboxylates containing electron-abundant aromatic substituents led to the construction of six-membered cyclic systems. Depending on the substrate properties and the Lewis acid applied, three types of products can be obtained: (1) 1,4-diarylcyclohexanes, (2) 1-aryl-1,2,3,4-tetrahydronaphthalenes, and (3) 9,10-dihydroanthracenes.     

Synthesis of Sb(VO3)3 and study of ternary system xNH4VO3?+?(1???x)(NH4)2HPO4?+?Sb2O3

Sb(VO₃)₃ has been synthesized by interaction between NH₄VO₃ and Sb₂O_3. The compound crystallizes in monoclinic system with lattice parameters: a = 17.150; b = 15.940; c = 14.600 Å and angle ?? = 90.50°. The scanning electronic microscopy shows thin flat plates measuring ~20 ??m along with detritus material. The synthesis was simulated by thermal analysis and the final product identified by X-ray diffraction. Thermal analyses of the ternary system xNH₄VO₃ + (1 ? x)(NH₄)₂HPO₄ + Sb₂O₃ lead to the formation of Sb(VO₃)₃ and SbPO₄ at 500 °C. At high temperature (900 °C), SbVO₄, SbOPO₄, VO and SbP₅O₁₄ are formed. The data of thermal analysis match with the composition of intermediate and final products. No solid solutions containing simultaneously PO ₄ ^?3 and VO ₄ ^?3 ions have been found.     

New Degree Spectra of Polish Spaces

Siberian Mathematical Journal - The main result is as follows: Fix an arbitrary prime $ q $ . A $ q $ -divisible torsion-free (discrete, countable) abelian group&nbsp; $ G $ has a&nbsp; $...     

Punctual definability on structures

We study punctual categoricity on a cone and intrinsically punctual functions and obtain complete structural characterizations in terms of model-theoretic notions. As a corollary, we answer a question of Bazhenov, Downey, Kalimullin, and Melnikov by showing that relational structures are not punctually universal. We will also apply this characterisation to derive an algebraic characterisation of relatively punctually categorical mono-unary structures.