P. P. Semyannikov

Saturated Vapor Pressure of Iridium(III) Acetylacetonate

The temperature dependency of the saturated vapor pressure of Ir(acac)3 has been measured by the method of calibrated volume (MCV), the Knudsen method, the flow transpiration method, and the membrane method. The thermodynamic parameters of phase transition of a crystal to gas were calculated using each of these methods, and the following values of ΔHT0 (kJ mol−1) and ΔST0 (J mol−1K−1), respectively, were obtained: MCV: 101.59, 156.70; Knudsen: 130.54, 224.40; Flow transpiration: 129.34, 212.23; Membrane: 95.45, 149.44Coprocessing of obtaining data (MCV, flow transportation method and Knudsen method) at temperature ranges 110−200°C as also conducted:ΔHT0 =127.9±2.1 (kJ mol−1 ); ΔST0 =215.2±5.0 (J mol−1 K−1 ).

Preparation of thin films of platinum group metals by pulsed MOCVD. II. Deposition of Ru layers

In situ high-temperature mass spectrometry is used to analyze the thermal decomposition of Ru(acac)3 and Ru(nbd)(allyl)2 vapor and possible schemes of thermal transformations on the heated surface. By pulsed MOCVD with in situ mass spectrometric control of deposition processes ultrathin Ru layers with a thickness of several nanometers are obtained. The role of the reaction medium, precursor nature, and deposition temperature in the formation of a nanocrystalline structure of the films is revealed. Ruthenium films with a compact continuous structure are formed from Ru(acac)3 and hydrogen at a deposition temperature of 340°C and below; an increase in the temperature results in the growth of nanogranular Ru layers. Regardless of deposition conditions, from Ru(nbd)(allyl)2 granular nanocrystalline Ru layers are formed

Preparation of metal-polymer composites through the thermolysis of Fe(II), Co(II), and Ni(II) maleates

Metal-polymer composites have been prepared through the thermolysis of the [M1(H2O)2(C4H2O4)] · H2O (M1 = Co(II), Ni(II)) neutral maleates and [M2(H2O)4(C4H3O4)2] (M2 = Fe(II), Co(II), Ni(II)) acid maleates. In the polymer matrix of the Fe-containing composite, we identified metal, Fe2O3, and Fe3O4 particles, with slight densification of the matrix around them. The polymer matrix of the cobalt maleate-derived composite contained four types of nanoparticles: α-Co, β-Co, and CoO in polymer shells and Co3O4 with no polymer shell. The decomposition of the nickel maleates yielded homogeneous nickel nanoparticles (4–5 nm) covered with two to five graphene layers. The Co-containing composite was found to be a dielectric. The Ni-containing composite exhibited variable range hopping conduction in the range T ≤ 50 K.

Transition-metal bimaleates and their solid solutions: Synthesis, structural, and thermoanalytical study

Transition-metal hydrogen maleates of composition M(C4H3O4)2 · 4H2O, where M = Mn, Fe, Co, and Ni, and their solid solutions were synthesized and characterized by X-ray crystallography, IR spectroscopy, mass spectrometry, and thermal analysis. X-ray crystallography and IR spectroscopy showed that both intramolecular and intermolecular H-bonds exist in these compounds. The generation of continuous substitutional solid solutions with cation substitution in these compounds was studied. The thermolysis mechanism was studied for both transition-metal hydrogen maleates and their solid solutions. The composite produced by thermolysis is stable up to 1200°C in flowing helium.

Synthesis and thermal properties of some lithium β-diketonates

Five new volatile lithium complexes were synthesized by reactions of lithium hydroxide monohydrate (LiOH · H2O) with β-diketones, namely, dipivaloylmethane (HDpm), hexafluoroacetylacetone (HHfa), trifluoroacetylacetone (HTfa), benzoyltrifluoroacetone (HBtfa), pivaloyltrifluoroacetone (HPta), and valeryltrifluoroacetone (HVta). The complexes obtained were studied by IR and electronic absorption spectroscopy, mass spectrometry, and comprehensive thermal analysis. The temperature dependence of the vapor pressure, which was obtained by the Knudsen effusion method with mass-spectrometric analysis of the vapor phase composition in the 400–450 K range, was used to calculate the standard thermodynamic parameters of the Li(Dpm) sublimation: ΔH°subl = 45.7 ± 1.7 kcal mol−1 and ΔS°subl = 77.9 ± 4.0 cal mol−1 K−1.

Novel N-Containing Precursors of Nickel(II) for Film Deposition by MOCVD

The synthesis of volatile nickel(II) complexes with Ncontaining ligands like R(O,N)C(CH3)CH2C(CH3)NR (R – H, radical group) was carried out in inert atmosphere. The substances were characterized by means of elemental analysis, IRand NMR-spectroscopy, melting point, mass spectrometry. The thermal behavior of the compounds in the solid state was investigated by the method of thermogravimetry and difference-scanning calorimetry (DSC) in vacuum and helium. The thermodynamic characteristics of the melting processes (m.p., ∆meltHm.p., ∆meltSm.p.) were also determined by DSC: m.p. 157.5 ± 2 and 247.2 ± 1,2oC, ∆meltHm.p. = 25 ± 2 and 41,7 ± 0,3 kDj/mol, ∆meltSm.p. = 58 ± 5 and 80,1 ± 1,2 Dj/mol K for Ni(N(Me)C(CH3)CHC(CH3)N(Me))2 and Ni(OC(CH3)CHC(CH3)NH)2 respectively. Using the Knudsen method with mass spectrometric registration of gas phase and static method with quartz zero-manometer the temperature dependences of saturated vapor pressure of complexes were studied, the standard thermodynamic parameters of enthalpy and entropy of sublimation process were determined (Fig.1). The standard thermodynamic parameters of ones of evaporation process were calculated from data on sublimation and melting processes. It was shown that complex with ketoamine ligand is more thermodynamically stable in solid state than diimine analogue whereas the last one is more volatile that O-containing compound. By means of in situ high temperature mass spectrometry the thermodecomposition process of Ni(N(Me)C(CH3)CHC(CH3)N(Me))2 vapor was studied in vacuum temperature range of destruction and gas byproducts were determined (Fig.2). At temperatures 130– 250oC the first step of decrease of ion current intensity for metal-containing ion is observed that is apparently connected with forming of oligomers on surface being accompanied by isolation of 2-methylamino-4methylimino-2-pentene to gas phase. The decomposition of just formed on surface structures is hypothetically beginning at temperatures upper 250oC and is accompanied by isolation of products pointed on Fig.2. to gas phase. On account of the analysis of temperature behavior of reaction products the scheme of mechanism of chemical transformation on heated surface was proposed. The complexes have been used as precursors for the Ni-containing film formation by Metal-Organic Chemical Vapor Deposition. The film decomposition conditions were chosen on the base of information about thermal behavior of complexes. The experiments were carried out in hydrogen at substrate temperature 320– 370oC. The films obtained were investigated by using different methods: SEM, XRD etc. 1,9 2,0 2,1 2,2 2,3 2,4 2,5 2,6 2,7 2,8 2,9 -3,5 -3,0 -2,5 -2,0 -1,5 -1,0 -0,5 0,0 0,5 1,0 1,5 2,0

Maleates of Mn(II), Fe(II), Co(II), and Ni(II) as precursors for synthesis of metal-polymer composites

Comparison was made for the structural, IR spectral, and thermoanalytical characteristics of normal [M1(H2O)2(C4H2O4)](H2O) (M1 = Co(II) and Ni(II)) and acid maleates [M2(H2O)4(C4H3O4)2] (M2 = Mn(II), Fe(II), Co(II) and Ni(II)). Only structures of acid maleates contain intramolecular asymmetric hydrogen bond whose asymmetry increases in the series of transition metal salts. Thermal decomposition of Co(II), Ni(II) normal maleates, and Mn(II), Fe(II), Co(II), Ni(II) acid maleates proceeds in three stages. Onset decomposition temperatures for the first and second stages decreases in the series of normal maleates Co(II) ≥ Ni(II) and increases in the series of acid maleates Fe(II) < Co(II) < Ni(II) ≈ Mn(II). Onset temperature of the third stage decreases in the series of both normal maleates Co(II) > Ni(II) and acid maleates Mn(II) > Fe(II) > Co(II) > Ni(II).

Thermal Properties of Some Volatile Titanium (IV) Precursors

The tensimetric study was carried out for TTIP, Ti[OEt]4 and Ti[DMAP]4 by means of static method with a quartz membrane zero-manometer and flow method using He as gas-carrier (the compounds were assumed to vaporize in a monomolecular form) in a wide range of temperatures. Temperature dependencies of saturated vapor pressure were measured; the evaporation thermodynamic parameters have been calculated (Table 1). Data obtained for TTIP can be compared with values calculated from literature data [1, 2].

Thermolysis of copper(II) salts of maleic acid. Synthesis of metal-polymer composites

The thermal decomposition of neutral ([Cu(H2O)(C4H2O4)]) and acidic ([Cu(H2O)4](C4H3O4)2) maleates can conventionally be divided into four stages: (1) dehydration, (2) polymerization, (3) isomerization of the maleate ion to the trans form with the simultaneous reduction Cu(II) → Cu(I), and (4) decarboxylation of copper(I) fumarate. The third and fourth stages of the decomposition of these salts coincide. The residue after the thermolysis of copper(II) maleates in a He flow is a composite consisting of aggregates from 50 nm to several microns in size. Spherical conglomerates (50–200 nm) containing many spherical Cu particles (5–10 nm) are incorporated into the organic polymer matrix of these aggregates.

Thermal decomposition of transition metal biphthalates [M(H2O)6](C8H5O4)2 (M = Fe, Co, Ni) and copper biphthalate [Cu(C8H5O4)2(H2O)2]. Synthesis of metal-polymer composites

The decomposition of transition metal biphthalates [M(H2O)6](C8H5O4)2 (M = Fe, Co, Ni) and copper biphthalate [Cu(C8H5O4)2(H2O)2] was studied by thermal analysis and mass spectrometry. The decomposition was shown to proceed in three stages: the temperature of the third stage of decomposition decreased in the series of iron, cobalt, nickel, and copper biphthalates from 365 to 275°C. The mass spectrometric study showed the evolution of CO2, diphenylene C12H8, and fluorene (C6H4)2CH2 that at this stage. It was shown by electron scanning microscopy, X-ray diffraction analysis, and chemical analysis that the final thermolysis product of transition metal biphthalates was a composite consisting of the polymer and incorporated into it round submicronic aggregates with metallic particles inside.