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The total lifetime distributions for hydrogen bonds in snapshots of molecular dynamics simulations of water serve as a basis to identify a class of proper hydrogen bonds. Proper bonds emerge and break up when restructuring the surrounding area of the hydrogen bond networkwhich weakly depend on the properties of this individual bond, i.e., almost randomly. Therefore, the distribution of the bond lifetimes is described by an exponential function similar to the distribution of the mean free path time in gas. It is shown that proper hydrogen bonds are strong, long-lived, and tetrahedrally oriented bonds. They account for about 80% of the bonds in each snapshot. Thus, these bonds form the basis or framework of the hydrogen bond network of water. The other, improper bonds have a substantially shorter lifetime; these are weak, bifurcated, and quickly switching bonds.

X-ray diffractometry and positron annihilation life-time spectroscopy are applied to study the structural features of polymetallophenylsiloxane (PMOS) samples with the Si/M ratio corresponding to the metal valence state, namely, interplanar spacings ( d₀₀₁), coherentscattering region (CSR) sizes, cross-section areas of polymer chains ( s ) calculated by the Miller-Boyer method, and the degree of amorphousness (β). It is demonstrated that the direct proportional dependence between the logarithm of the interplanar spacing d₀₀₁ and the logarithm of the cross-section area s is observed for PMOSs. This is an inverse dependence relative to changes in the crystal chemical ion radius. The extraction of the iron ion from polyferrophenylsiloxane leads to a sharp decrease in the interplanar spacing, which turns out to be less than d ₀₀₁ in polyphenylsiloxanes, and also CSR increases due to a decrease in the diameter of the polymer chain. The positron annihilation life-time spectroscopy data show the observed direct dependence of the annihilation intensity ( I₃), the annihilation rate ( K₃), the degree of amorphousness on the PMOS cross-section area.

The results of a crystallographic analysis of the structures of CsFe₂S₃, Tl₂PbZrS₄, and Tl₂PbGeS₄ with a 1:1 cation-anion ratio are used to identify a joint F sublattice for Cs and S in the first compound and two separate F sublattices for cations and anions in the second compound (the PbS structural type). The substitution of the small Ge⁴⁺ (with its tetrahedral coordination by sulfur) for Zr⁴⁺ in the composition results in an increase in the unit cell volume, i.e., a decrease in the packing density for both cations and anions in the structure of the third compound. In the absence of regular F sublattices, there are “two-dimensional” orderings, typical of the PbS type, for the atomic positions in the projections of this structure.

A crystallographic analysis is conducted of the structures of orthorhombic mineral sicherite TlAg₂(As,Sb)₃S₆, monoclinic synthetic sulfide Tl₃Ag₃Sb₂S₆ , and triclinic mineral raberite Tl₅Ag₄As₆SbS₁₅. In the first two structures, the large and heavy Tl⁺ cation forms, together with the other cations, ordered “skeletal” frameworks with F and I cation sublattices that are close to cubic ones. In the structure of raberite, the Tl and Ag cations undergo, together with the sulfur anions, two-dimensional ordering by a zone of closely packed crystallographic planes, which generate a pseudohexagonal symmetry. The deviations from the 1 cation/anion stoichiometry are compensated: in the second structure, by a local consolidation of cations (to a distance Tl-Ag = 2.96 Å) and, in the third structure, through the formation of a dumbbell pair As-Ag (2.68 Å), which occupies one position in the sublattice.

A novel trinuclear nickel(II) ONO pincer complex [Ni(pydc)₂]₂[Ni(H₂O)₅]×2H₂O×2(C₆H₁₅N) (1) (H₂pydc = 2,6-pyridinedicarboxylic acid) is synthesized by the reaction between Ni(OAc)₂ and H₂pydc in acetonitrile in the presence of triethylamine. A detailed study through single crystal XRD reveals that the compound crystallizes in the triclinic space group P -1 with cell parameters a = 11.6646(3) Å, b = 14.0999(4) Å, c = 16.4633(5) Å, a = 80.189(2)°, b = 75.539(2)°, g = 67.017(2)°. Both terminal Ni(II) centers are coordinated to two ONO pincer ligands (pydc) bridged by the nickel penta aqua unit. Further, triethyl ammonium neutralizes the trinuclear complex.

The [Pd(dpa)(tsser)] complex (1) is prepared from the reaction of PdCl₂ and 2,2'-dipyridylamine (dpa) with 4-toluenesulfonyl-L-serine (tsserH₂). This complex is characterized by spectral methods (IR, UV-Vis, ¹H NMR, and luminescence), elemental analysis, thermal analysis (TG, DTA), and single crystal X-ray diffraction. X-ray structure determinations show that in this complex, Pd^II atoms are four-coordinated in a distorted square-planar configuration by two N atoms from a bidentate 2,2'-dipyridylamine ligand and one N atom and one O atom from a bidentate tsser^2- ligand.

For the first time, a mononuclear biligand complex of lanthanum nitrate with bicyclic bisurea (4,4,10,10-tetramethyl-1,3,7,9-tetraazospiro[5.5]undecane-2,8-dione, or spirocarbon, Sk) [La(C₁₁H₂₀N₄O₂)₂(H₂O)₂× ×(NO₃)₃] (I) is synthesized and its structure is determined by direct single crystal XRD. The crystals of I are monoclinic: space group P 2₁/ c , a = 11.1989(15) Å, b = 13.015(2) Å, c = 24.153(2) Å, b = 101.129(12)°, V = 3454.3(8) ų, d _calc = 1.618 g/cm³, Z = 4, CCDC 985760. The structure is molecular. The lanthanum cation is coordinated by two oxygen atoms of two organic ligand molecules, two water molecules, and three bidentate nitrate anions. The coordination number of lanthanum is ten; the coordination polyhedron is an irregular 10-vertex polyhedron. The crystal of I represents a non-merohedral twin with the components turned by 180° along the a axis; the relative weights of the components are 0.76:0.24. To confirm the purity of the sample of I, the powder XRD pattern was refined using the Rietveld method; the unit cell parameters at room temperature are as follows: a = 11.2777(4) Å, b = 13.0774(5) Å, c = 24.3453(9) Å, b = 101.129(3)°, V = 3523.0(2) ų.

The structure of xymedone iodo methylate is determined by X-ray crystallography. The molecular and crystal structure of the compound is analyzed in comparison with xymedone whose X-ray crystallographic data have been obtained previously. The molecular and electronic structures of both compounds and noncovalent interactions in the ionic pair of xymedone iodo methylate are analyzed using the data of the quantum topological calculations. It is shown that the presence of the iodine anion results in an increase in the delocalization of the p electron density inside the heterocyclic moiety, the charge redistribution inside the molecule, and consequently, in significant distinctions in crystal packings.

By small-angle X-ray scattering a gadolinium triacetate-undecane-water system is studied at hydrotrope concentrations of 0.05-0.5 М on the line of saturation with undecane at 298 K. In the ternary system mixed hydrotrope/undecane lamellar micelles form with lateral dimensions of hydrophilic and hydrophobic plates of 0.4 nm. It is shown that the Gibbs energy of the hydrophobic interaction and the micelle shape are determined by a joint (cooperative) effect of the hydrotrope and hydrocarbon on water.

The review includes comprehensive NMR data on platinum metals (^99,101Ru, ¹⁰³Rh, ¹⁰⁵Pd, ¹⁸⁷Os, ¹⁹⁵Pt) and ligand donor atoms (¹H, ¹³C, ^14,15N, ¹⁷O, ¹⁹F, ³¹P) of metal complexes in aqueous solutions. A systematic analysis of NMR spectroscopy techniques is presented with focus on the measurements of NMR parameters in these systems. A novel concept referred to as coordinate shift is introduced, allowing interpretation of NMR spectra of platinum metal complexes. The review contains an encyclopedic NMR database covering a period of over 50 years from the first measured NMR spectra of platinum metals to 2014.