Natalia B. Morozova

Saturated Vapor Pressure and Crystal Structure of Bis-(2-imino-4-pentanonato)copper(II)

A comprehensive study of copper(II) bis-ketoiminate including tensimetric analysis of sublimation and structure solution has been carried out. The temperature dependence of saturated vapor pressure over Cu(ki)2 crystals derived by the flow method is expressed by the equation lnP(atm)} = 25.31-13750/T, ΔHsubl = -114.2 ± 1.3 kJ· mole-1,Δ Ssubl =210.2 ± 3.0> J· mole-1 · K-1. Crystal data for CuO2N2C10H16: a=15.143(3), b=16.681(8), c=13.795(32) Å, space group Ccca, Z=12, dcalc = 1.47 g/cm3, R=0.029. The structure is molecular and consists of crystallographically independent Cu(ki)2 complexes of two types, one with a cis structure and the other with a cis–trans disordering. The copper atom has a plane square environment of two oxygen and two nitrogen atoms. In the cis isomer, Cu–O 1.938 and Cu–N 1.895 Å; in the disordered complex, all four Cu–O(N) distances are 1.901 Å.

SYNTHESIS AND CRYSTAL STRUCTURE DETERMINATION OF IRIDIUM(III) ACETYLACETONATE AND ITS BR- AND I-SUBSTITUTED ANALOGS

Abstractγ-Halogen-substituted iridium(III) acetylacetonates of general formula Ir(acacX)3,where acacX = CH3-CO-CX-CO- CH3,X =Br, I, were synthesized. The compounds are characterized by melting points and chemical analysis data for C, H, Br, and I. An X-ray diffraction analysis was performed for iridium(III) acetylacetonate and its y-substituted analogs, crystal data were obtained, and crystal structures were determined. The crystals are monoclinic;the structures are molecular. Crystal data: Ir(acac)3- IrO6C15H21,a = 13.900(2), b = 16.440(3), c = 7.494(2) å, γ =98.63(2)‡, V= 1693.2 å3,space group P21/b,Z = 4, dcalc =1.92 g/cm3,sin θ/λmax= 0.703, Fhkl= 2841, R = 0.044. Ir(acacBr)3- IrBr3O6C15H18,a = 12.794(2), b = 15.753(2), c = 9.990(2) å Β = 105.76(2)‡, V= 1937.6 å3,space group P21/n,Z =4, dcalc =2.49 g/cm3, sinθ/λmax= 0.702, Fhkl= 1748, R = 0.048. Ir(acacI)3- M3O6C15H18,a = 12.855(2), b = 10.136(2), c =16.338(3)å, Β = 104.6(2)‡, V=2059.8å3,space group P21/n, Z =4, dcalc = 2.79g/cm3, θmax =25‡, Fhkl= 2817, R =0.032. The Ir..Ir distances were estimated to be > 7.49 å for Ir(acac)3 and > 8.10 å for Ir(acacBr)3 and Ir(acacl)3.If the estimate is limited to 10 å, the intermolecular coordination number (ICN) in the structures is 10.

Synthesis, structure, and thermal properties of fluorinated cesium beta-diketonates

Four fluorinated cesium beta-diketonates, Cs(CF3COCHCOCF3) (Cs(hfac)), Cs(CF3COCHCOCH3) (Cs(tfac)), Cs(OH2)((Me)3CCOCHCOCF3) (Cs(OH2)(ptac)), and Cs(OH2)(PhCOCHCOCF3) (Cs(OH2)(btfac)), were synthesized by interaction of the corresponding beta-diketone and Cs2CO3 in Et2O. The formation of Сs(CF3C(OH)2CH2C(OH)2CF3)(CF3COO) or Cs(CF3C(OH)2CH2COCH3)(tfac) was shown to be dependent on the reaction conditions. The compounds were characterized by elemental analysis, single crystal X-ray diffraction, and TG/DTA analysis. All compounds have ionic structures organized into pseudo chains (in the case of Cs(hfac) and Cs(CF3C(OH)2CH2COCH3)(tfac)) or pseudo layers (in other cases). According to the TG data Cs(hfac), Cs(tfac), Cs(OH2)(ptac,) and Cs(OH2)(btfac) decompose in inert atmosphere within the temperature range 30–550 °C.

Thermal properties of volatile ruthenium(III) complexes

Complexes of ruthenium(III) with the following beta-diketone derivatives: 2,4-pentanedione (Ru(acac)3), 1,1,1,6,6,6-hexafluoro-2,4-pentanedione (Ru(hfac)3), and 2-methoxy-2,6-dimethyl-3,5-heptanedione (Ru(mdhd)3) were synthesized, purified, and identified by chemical analysis and melting points. By difference-scanning calorimetry (DSC) in vacuum the thermodynamic characteristics of melting processes were defined. Using the static method with quartz membrane zero-manometer, the temperature dependencies of saturated and unsaturated vapor pressure were obtained for Ru(hfac)3. The standard thermodynamic characteristics of vaporization processes enthalpy ∆HT* and entropy ∆S°T* were determined.

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

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].

Synthesis of ruthenium(iii) and rhodium(iii) tris-acetylacetonates and palladium(ii) bis-ketoiminate using microwave heating

Preparation of ruthenium(iii) and rhodium(iii) tris-acetylacetonates and palladium(ii) bisketoiminate (Pd(i-acac)2) under microwave irradiation using different synthetic conditions, both in the solid-phase and in solution, was studied with precise control of parameters. In the solid-phase systems, the preparation of the target product was hindered. The efficiency of the microwave heating increased when liquid phases of the reagent mixtures were used. For Pd(i-acac)2, the highest yield was achieved under elevated temperature of the process, with the reaction time decreasing to several minutes. A laboratory procedure for the microwave synthesis of ruthenium(iii) and rhodium(iii) tris-acetylacetonates and palladium(ii) bis-ketoiminate in aqueous solutions was developed, which allowed us to obtain them in 85, 55, and 80% yields, respectively. These yields are higher than those reported in the literature, with the process becoming considerably less time consuming and laborious.

Chemical Composition and Structure of Thin Films Produced by Chemical Vapor Deposition

This paper reports results from studies of the chemical composition and structure of semiconducting, dielectric, and metallic films produced from molecular precursors by the chemical vapor deposition method. A study was made of films of zinc sulfides, mixed copper, cadmium, and zinc sulfides, boron nitride, carbonitride, silicon carbonitride, and iridium films. It is shown that the use of metal compounds with different ligands (zinc and manganese) enables production of zinc sulfide films in which manganese ions are uniformly incorporated into the zinc sulfide crystal lattice to substitute zinc at the lattice sites. For the films of simple and mixed cadmium, copper, and zinc sulfides, the film structure depends on the type of substrate. The thin layers of mixed cadmium and zinc sulfides are asubstitution solution with a hexagonal structure. The thin layers of boron nitride produced from borazine exhibit a nanocrystalline structure and are a mixture of cubic and hexagonal phases. Composite layers were produced from alkylamine boranes and their mixtures with ammonia. Depending on synthesis conditions, the layers are mixtures of hexagonal boron nitride, carbide, and carbonitride or pure boron nitride. Using silyl derivatives of asymmetric dimethylhydrazine containing Si—N and C—N bonds in the starting molecule, we produced silicon carbonitride films whose crystal habit belongs to a tetragonal structure with lattice parameters a = 9.6 Å and c = 6.4 Å. The iridium films obtained by thermal decomposition of iridium tris‐acetylacetonate(III) on quartz substrates in the presence of hydrogen have a polycrystalline structure with crystallite sizes of 50 to 500 Å. A method for determining grain‐size composition was proposed, and grain shapes for the iridium films were analyzed. The influence of substrate temperature on the internal microstructure and growth of the iridium films is demonstrated. At the iridium–substrate interface, a transition layer forms, whose composition depends on the substrate material and deposition conditions.