Reaction of the PtIII complex, [Pt2(μ-NHCOMe)4Cl2], with 1,10-phenanthroline and solid-state thermolysis of 1,10-phenanthroline-containing platinum blues

Platinum blues with the composition Pt(phen)(NHCOMe)₂X (phen is 1,10-phenanthroline, X = NO₃ ^?, CF₃SO₃ ^?, or Cl^?), were synthesized starting from the complex [Pt₂(NHCOMe)₄Cl₂]. The resulting compounds apparently have a polymeric structure with metal centers in different valence states. The reaction of the complex Pt(phen)(NHCOMe)₂NO₃ with H₂O affords crystalline binuclear acetamidate [Pt^III ₂(phen)₂(??-NHCOMe)₂(NHCOMe)₂](NO₃)₂, whose structure was determined by X-ray diffraction. The reaction of the complex Pt(phen)(NHCOMe)₂NO₃ with HCF₃SO₃ leads to the decomposition of the starting compound, the reduction of the Pt atoms, and the formation of the complex [Pt^II ₂(phen)₄](CF₃SO₃)₄. The thermal decomposition of the resulting complexes, as well as the complexes [(phen)Pt-(??-NHCOMe)₂Pt(phen)]₂(NO₃)₄ and [Pt(phen)Cl₂], under an inert atmosphere was studied by DSC and TGA. Metallic platinum nanopowders are thermal decomposition products of the complexes under study.     

Some trends observed in [60]fullerene polymerization activated by butyllithium isomers

It was found that BuLi plays a dual role in the polymerization of [60]fullerene: the addition of a first molecule of BuLi makes C₆₀ tending to polymerize, while the addition of more BuLi molecules to the other reactive double bonds impedes this process.     

Structural parameters of glycine zwitterion hydration from the data of the integral equation method in the RISM approach

The structural parameters of glycine zwitterion in water were studied by means of the integral equation method in the framework of the RISM approximation. According to calculations, five water molecules are located in the nearest environment of the -NH ₃ ⁺ group, and two of them are the H-bonded with this group. At the same time, six water molecules are located in the nearest environment of the ?COO^? group, and three of them are the H-bonded with this group. The average number of water molecules in the first hydration shell of ?CH₂ group is four. It has been shown that the probability of hydrogen bond formation between water molecules and the hydrogen atom H1 of the ?NH ₃ ⁺ group is low, and there is no H-bonding between water molecules and the nitrogen atom the ?NH ₃ ⁺ group.     

Crystal structure and magnetic properties of Ba-ordered manganites Ln0.70Ba0.30MnO3−δ (Ln = Pr, Nd)

The structure and magnetic properties of the Ba-ordered state in solid solutions of manganites Ln_0.70Ba_0.30MnO_3?δ (Ln = Pr, Nd) with a cation ratio Ln³⁺/Ba²⁺ ? 1 are studied experimentally. The samples are obtained by two-stage synthesis. The initial stoichiometric Ba-disordered solid solutions Ln_0.70Ba_0.30MnO₃ synthesized in air according to traditional ceramic technology are characterized by the orthorhombic (Imma, Z = 4) perovskite-like unit cell and are ferromagnets with Curie temperatures T _C ≈ 173 and ≈ 143 K for Pr and Nd, respectively. The average size <D> of a crystalline in the initial samples is 5 μm. It is found that annealing of the initial samples in a vacuum of P[O₂] = 10^?4 Pa leads to their separation into three phases: (1) the anion-deficient ordered LnBaMn₂O₅ phase described by a tetragonal (P4/mmm, Z = 2) perovskite-like unit cell, as well as the phases (2) Ln₂O₃ (P $\bar 3$ m1, Z = 1) and (3) MnO (Fm $\bar 3$ m, Z = 2). Reduction leads to the formation of a nanocomposite with an average crystallite size <D> = 100 nm. Anion-deficient Ba-ordered phases of LnBaMn₂O₅ exhibit ferrimagnetic properties with Néel temperatures T _N ≈ 113 and ≈123 K for Pr and Nd, respectively. Annealing of anion-deficient samples in air at a moderate temperature of T = 800°C does not change the average size of the nanocrystallite, but noticeably alters their phase composition. Stoichiometric nanocomposites consist of two perovskite-like phases: (1) the Ba-deficient ordered stoichiometric phase LnBaMn₂O₆, which is described by a tetragonal (P4/mmm, Z = 2) unit cell and has the Curie temperatures T _C ≈ 313 (Pr) and ≈303 K (Nd), and (2) the Ba-disordered superstoichiometric phase Ln_0.90Ba_0.10MnO_3+δ, which is described by an orthorhombic (Imma, Z = 4) unit cell and has Curie temperatures T _C ≈ 138 (Pr) and ≈123 K (Nd). The two magnetic phases of the Ba-ordered nanocomposite are exchange-coupled. For the low-temperature magnetic phase, a temperature hysteresis is observed at ΔT ≈ 22 K in a field of 10 Oe and at ΔT ≈ 5 K in a field of 1 kOe. It is shown that states with different degrees of ordering of cations in the A sublattice can be obtained employing different technological conditions of treatment. The significant changes in the magnetic properties of Ba-ordered nanocomposites are explained on the basis of chemical phase separation taking into account the effect of compression, which is a consequence of the action of chemical (cation ordering) and external (surface tension) pressures.