Metal–Organic Chemical Vapor Deposition (MOCVD) is a vigorously growing technique for film production. Accurate vapor pressure, as well as sublimation and fusion thermodynamics of the precursor used in MOCVD is paramount for achieving the desired film composition, growth rates, uniformity, and functionality. Herein, we present the results of thermodynamic study of magnesium heteroligand complexes with aromatic neutral ligands Q = bipy (2,2′-bipyridine) or phen (1,10-phenanthroline), and hfac (1,1,1,5,5,5-hexafluoropentane-2,4-dionate anion). The complexes have been synthesized, purified, and identified. Differential scanning calorimetry has been applied to measure the melting temperature and fusion enthalpy. Saturated vapor pressures over the solid compounds were measured by a transpiration method. Thermodynamic characteristics of enthalpy and entropy of the sublimation process have been calculated from the experimental data at average temperature and at 298.15 K; the p(T) equations operating over a wide temperature range have been derived. [Mg(bipy)(hfac)2] was tested as an MOCVD precursor. Thermodynamic simulation has been executed to outline the conditions for film deposition formation in various reactive atmospheres. The critical importance of precise thermodynamic data on sublimation has been highlighted through a set of MOCVD experiments on the production of MgF2 films.

New data are obtained on the thermal behavior and sublimation and melting of (pivaloyltrifluoroacetonato)(cyclooctadiene-1,5)iridium [Ir(cod)(ptac)]. The condensed phase is studied via differential scanning calorimetry, and the complex’s temperature of melting is determined along with its enthalpy and entropy of fusion: Tmelt = 405.9 ± 0.5 K; Δ_fusH_m^^∘ (Tmelt) = 20.4 ± 0.3 kJ mol−1; Δ_fusS_m^^∘ ; (Tmelt) = 50.3 ± 0.7 J mol−1 K−1. The temperature dependence of the saturated vapor pressure of [Ir(cod)(ptac)] in the 363–397 K range of temperatures is obtained from the flow. The thermodynamic characteristics of sublimation are calculated at the average temperature of the experimental range and 298.15 K: Δ_sublH_m^^∘ (Tav) = 102.0 ± 1.8 kJ mol−1; Δ_sublS_m^^∘ (Tav) = 188.5 ± 3.3 J mol−1 K−1; Δ_sublH_m^^∘ (298.15 K) = 107.3 ± 2.9 kJ mol−1; and Δ_sublS_m^^∘ (298.15 K) = 204.1 ± 5.7 J mol−1 K−1. The resulting values are compared to those of similar compounds of iridium(I) and other β-diketones, [Ir(cod)(β-dik)]. The results form the basis for developing a way of assessing the thermodynamic properties of complexes [M(cod)(β-dik)], which is needed when compounds (e.g., [Ag(cod)(β-dik)]) are hypersensitive to heating and it is impossible to determine reliable thermodynamic characteristics experimentally in order to establish the optimum conditions for the gas-phase deposition of etal-containing coatings.

Crystals of copper bis(heptafluorodimethyloctanedionate) (Cu(fod)2) have been grown by evaporation of solvent from solutions. Crystals of monoclinic syngony (I) have been obtained from toluene, while crystals of monoclinic (I) and triclinic (II) syngony have been obtained from acetonitrile. Crystallographic data: P21/c, a = 13.1863 (6), b = 9.8118 (4), c = 10.6997 (6), β = 113.633(2)° for I; 1̅ , a = 10.7941(12), b = 11.4759(14), c = 12.5263(13), α = 115.350(4)°, β = 102.957(4)°, γ = 100.999(4)° for II. Crystal packings I and II have the same structure of molecules. Crystal structures I and II are molecular and consist of discrete Cu(fod)2 molecules. Temperature dependences for saturated vapor pressure have been obtained by flow method for liquid and crystalline (phase I) Cu(fod)2 in the range 314–393 K. Thermal stability of the compound is determined, thermodynamic parameters of sublimation and evaporation have been established.

Разнолигандные комплексы магния со фторированными β-дикетонами и диаминами перспективны в качестве прекурсоров для получения тонких пленок MgF2 методом химического осаждения из газовой фазы (MOCVD). В настоящей работе проведено комплексное исследование наиболее летучего на данный момент представителя этого семейства, [Mg(tmeda)(ofhac)2] (tmeda = (CH3)2NCH2CH2CN(CH3)2, ofhac = C2F5COCHCOCF3–. Методом ДСК определены характеристики процесса плавления (Тпл. = 354.4 ± 0.6 K, ∆пл.Н = 23.3 ± 0.9 кДж/моль) и показано, что комплекс стабилен в конденсированной фазе как минимум до 473 K. Исследована температурная зависимость теплоемкости в интервале 298–403 K. Методом переноса в потоке гелия измерены температурные зависимости давления насыщенного пара над твердым (318–352 K) и жидким (358–393 K) комплексом. Определены термодинамические параметры сублимации и испарения. С помощью квантово-химических расчетов (B3LYP-D3(BJ) / def2-SVP, def2-TZVP и OPBE / TZ2P-J) проведено сравнение возможных изомеров комплекса (по положению C2F5-заместителей).

Mixed-ligand complexes of magnesium with fluorinated β-diketones and diamines are promising as precursors for the preparation of thin MgF2 films by metal-organic chemical vapor deposition (MOCVD). The currently most volatile representative of this family, [Mg(tmeda)(ofhac)2] (tmeda = (CH3)2NCH2CH2CN(CH3)2, ofhac = C2F5COCHCOCF _3^ - ), was studied. The melting process was characterized by DSC (Tm = 354.4 ± 0.6 K, ∆mH = 23.3 ± 0.9 kJ/mol). The complex was shown to be stable in the condensed phase up to at least 473 K. The temperature dependence of the heat capacity was studied in the range 298–403 K (DSC, using sapphire as a standard). The temperature dependences of the saturated vapor pressure over the solid (318–352 K) and liquid (358–393 K) complex were measured by transport in a helium flow. The thermodynamic parameters of sublimation and vaporization were determined. The possible isomers of the complex (based on the position of the C2F5 substituents) were compared using quantum-chemical calculations (B3LYP-D3(BJ)/def2-SVP, def2-TZVP, and OPBE/TZ2P-J).

The crystal structure of new isostructural complex Tb(thd)3 (1), Ho(thd)3 (2) (sp. gr. Pmn21) and Tb(thd)3 (3), Dy (thd)3 (4), Er(thd)3 (5), Yb(thd)3 (6) (sp. gr. Pna21) are determined. The crystal structures of 1-6 are molecular and consist of discrete monomeric Ln(thd)3 molecules (Ln = Tb, Ho, Dy, Er, Yb). The samples of Ln(thd)3 in the solid state have been investigated over the temperature range from 120 to 300 K using differential scanning calorimetry. DSC curves Ln(thd)3 exhibit a single endothermic peak of the crystal-to-crystal reversible phase transition. First-order phase transition is accompanied by an abrupt change in the volume of the unit cell. The quantum chemical calculations allow one to conclude that the electronic structures of the three modifications for Tb tris-2,2,6,6-tetramethylheptane-2,4-dionates are some different. It has been shown that for Tb(III) complexes with thd-ligands the modification I is energetically more stable.

Tensimetric studies were carried out to determine temperature-dependent saturated vapor pressures and calculate thermodynamic characteristics of vaporization for R3N·BH3 (R = Me or Et) alkylamine boranes. These compounds have sufficient volatility and thermal stability to be used as precursors in vapor deposition processes to produce films based on phases of the B–C–N system. Triethylamine borane (TEAB) was used to synthesize boron carbonitride films at 773 and 873 K. The resulting layers were characterized by ellipsometry, atomic force and scanning electron microscopy, FTIR, Raman, and energy dispersive spectroscopies. The conditions for the production of continuous homogeneous films consisting of nanoparticles 20–60 nm in size aggregated into larger pseudohexagonal particles were determined. The surfaces of the films have an average and root mean square roughness, equal to 0.8 and 1.0 nm, respectively.

We report an investigation into 1,4-Bis-N,N-(trimethylsilyl)piperazine (BTMSP) as a novel precursor for the synthesis of silicon carbonitride films by chemical vapor deposition (CVD). The thermal stability, temperature dependence of vapor pressure and thermodynamic constants of the evaporation process of BTMSP were determined by static tensimetry with a glass membrane zero manometer. The transformation of the compound in low-power (25 W) plasma conditions was investigated by optical emission spectroscopy. It was shown that BTMSP undergoes destruction, accompanied by H and CH elimination and CN formation. SiCN(H) films were deposited in a hot-wall plasma-enhanced CVD reactor. The optical properties of the films were studied by spectral ellipsometry (refractive index: 1.5–2.2; absorption coefficient: 0–0.12) and UV–Vis spectroscopy (transmittance: up to 95%; optical bandgap: 1.6–4.9 eV). Information on the aging behavior of the films is also provided. The transformation of the films occurred through water adsorption and the formation of Si–O bonds with the degradation of Si–H, N–H and Si–CHx–Si bonds.

Scandium(III) benzoyltrifluoroacetonate [Sc(btfac) 3 ] was synthesized, purified, and characterized by elemental analysis and 1 H NMR spectroscopy. Its structure was determined by single-crystal X-ray diffraction at 150 K. The complex has a molecular structure and is an axial isomer. All ligands in it are bidentate-cyclic coordinated; scandium is in a distorted octahedral environment, d (Sc–O) = 2.0681(2)–2.094(2) Å. There are two types of stacking interactions. The thermal properties in the condensed phase were studied by thermal analysis and differential scanning calorimetry (DSC). The temperature, enthalpy, and entropy of melting of the complex were determined as 399.1 ± 0.5 K, Δ_mH_T_m^^∘ = 36.8 ± 1.3 kJ/mol, and Δ_mS_T_m^^∘ = 92.2 ± 3.3 J/(K mol), respectively. The temperature-dependent saturated vapor pressure of [Sc(btfac) 3 ] was determined in the temperature range 413–443 K by the flow (transpiration) method. The thermodynamic characteristics of vaporization at an average temperature were calculated: Δ_vapH_430^^∘ = 135 ± 4 kJ/mol, and Δ_vapS_430^^∘ = 212 ± 9 J/(K mol). The structure and thermal properties of scandium benzoyltrifluoroacetonate were compared to those of similar scandium tris-β-diketonate complexes.

Crystal structure, thermal stability, and the process of scandium tris - methylcyclopentadienyl Sc(MeCp) 3 evaporation are studied. It is shown by XRD that crystals of this compound with the C 2/ c space group and the following parameters at 150 K are formed from the gas phase and from the solution: a = 7.9568(4) Å, b = 13.7620(6) Å, c = 28.239(2) Å, β = 107.4860(10)°, V = 2949.3(3) Å 3 , Z = 8, D calc = 1.217 g/cm 3 . The violation of the crystal packing order is manifested as diffuse scattering accompanied by single-crystal Bragg diffraction. The obtained data suggest that the complex has the Sc(η 5 -MeCp) 2 (η 1 -MeCp) structure with Sc– Z distances equal to 2.26-2.37 Å, where Z is the center of the η 5 -MeCp species or the C atom (for η 1 -MeCp). The NMR data obtained for the Sc(MeCp) 3 samples, which were kept for 7 days at 423 K, 453 K, and 483 K, indicate that the substance undergoes noticeable decomposition only at the highest temperature. Temperature dependences of the saturated vapor pressure of the complex are measured independently by the flow method (transpiration) (392-469 K) and by the static method (441-514 K). As a result of joint processing of the tensimetry data, the following thermodynamic parameters of Sc(MeCp) 3 evaporation are determined: Δ ev H 0 (458.5) = 82.5±1.1 kJ/mol, Δ ev S 0 (458.5) = 135±2 J/(mol·K).

Tensimetric studies were carried out to determine temperature-dependent saturated vapor pressures and calculate thermodynamic characteristics of vaporization for R 3 N·BH 3 (R = Me or Et) alkylamine boranes. These compounds have sufficient volatility and thermal stability to be used as precursors in vapor deposition processes to produce films based on phases of the B–C–N system. Triethylamine borane (TEAB) was used to synthesize boron carbonitride films at 773 and 873 K. The resulting layers were characterized by ellipsometry, atomic force and scanning electron microscopy, FTIR, Raman, and energy dispersive spectroscopies. The conditions for the production of continuous homogeneous films consisting of nanoparticles 20–60 nm in size aggregated into larger pseudohexagonal particles were determined. The surfaces of the films have an average and root mean square roughness, equal to 0.8 and 1.0 nm, respectively.

To expand the library of volatile magnesium precursors certified for effective use in chemical gas-phase deposition of the corresponding oxide or fluoride layers, a thermodynamic study of the mixed ligand complex Mg(tmeda)(btfac) 2 (tmeda is N , N , N ', N '-tetramethylethylenediamine, btfac is benzoyl trifluoroacetonate) have been performed. The melting process has been studied using DSC ( T m = 459.4 ± 0.3 K, Δ_mH_4594^^∘ = 42.9 ± 0.4 kJ/mol); the sublimation process has been studied using the flow (transfer) method in the temperature range 407–447 K ( Δ_sublH_427^^∘ = 163 ± 6 kJ/mol, Δ subl S 427 = 293 ± 14 J/(mol K)). The substance passes into the gas phase with partial decomposition. Thermodynamic modeling of the composition of condensed phases formed from Mg(tmeda)(btfac) 2 with the addition of H 2 or O 2 has been performed depending on the temperature (700–1300 K), total pressure (133–13 332 Pa), and the ratio of the reagent gas to the precursor (0–300). The data obtained can be used to determine the experimental parameters of the processes for obtaining functional layers. Comparison of the results with a similar trifluoroacetylacetonate complex made it possible to quantitatively reveal the effect of replacing the methyl group in the anionic ligand with a phenyl one.

Синтезирован, очищен и изучен методами элементного анализа и ПМР-спектроскопии бензоилтрифторацетонат скандия(III) [Sc(btfac) 3 ]. Методом РСА при 150 K определена его структура. Комплекс имеет молекулярное строение и является ос -изомером. Все лиганды координированы по бидентатно-циклическому типу, скандий находится в искаженно-октаэдрическом окружении, d (Sc–O) = = 2.0681(2)–2.094(2) Å. Реализуются два вида стэкинг-взаимодействий. Термические свойства в конденсированной фазе исследованы методами термического анализа и дифференциальной сканирующей калориметрии, определены температура (399.1 ± 0.5 K), энтальпия ( \({{\Delta }_{{{\text{{п}{л}}}}}}H_{{{{T}_{{{\text{{п}{л}}}}}}}}^{^\circ }\) = 36.8 ± 1.3 кДж/моль) и энтропия плавления ( \({{\Delta }_{{{\text{{п}{л}}}}}}S_{{{{T}_{{{\text{{п}{л}}}}}}}}^{^\circ }\) = 92.2 ± 3.3 Дж/(K моль)) комплекса. Методом потока (переноса) получена температурная зависимость давления насыщенного пара [Sc(btfac) 3 ] в интервале температур 413–443 K, на основании которой рассчитаны термодинамические характеристики процесса испарения при средней температуре: \({{{\text{\Delta }}}_{{{\text{{и}{с}{п}}}}}}H_{{430}}^{^\circ }\) = 135 ± 4 кДж/моль, \({{{\text{\Delta }}}_{{{\text{{и}{с}{п}}}}}}S_{{430}}^{^\circ }\) = 212 ± 9 Дж/(K моль). Проведено сравнение строения и термических свойств бензоилтрифторацетоната скандия(III) с трис -β-дикетонатными комплексами скандия.

To expand the library of volatile magnesium precursors certified for effective use in chemical gas-phase deposition of the corresponding oxide or fluoride layers, a thermodynamic study of the mixed ligand complex Mg(tmeda)(btfac)2 (tmeda is N,N,N',N'-tetramethylethylenediamine, btfac is benzoyl trifluoroacetonate) have been performed. The melting process has been studied using DSC (Tm = 459.4 ± 0.3 K,= 42.9 ± 0.4 kJ/mol); the sublimation process has been studied using the flow (transfer) method in the temperature range 407–447 K (= 163 ± 6 kJ/mol, ΔsublS427 = 293 ± 14 J/(mol K)). The substance passes into the gas phase with partial decomposition. Thermodynamic modeling of the composition of condensed phases formed from Mg(tmeda)(btfac)2 with the addition of H2 or O2 has been performed depending on the temperature (700–1300 K), total pressure (133–13 332 Pa), and the ratio of the reagent gas to the precursor (0–300). The data obtained can be used to determine the experimental parameters of the processes for obtaining functional layers. Comparison of the results with a similar trifluoroacetylacetonate complex made it possible to quantitatively reveal the effect of replacing the methyl group in the anionic ligand with a phenyl one.

Methods for the synthesis and purification of dimethyldi(allylamino)silane, ethyldi(allylamino)silane, and methyltri(allylamino)silane were developed. The individuality and structure of the compounds were confirmed by the data of elemental analysis, IR and 1H, 13C, 29Si NMR spectroscopy. According to tensimetric data, the obtained compounds have sufficient volatility and thermal stability to be used as as precursors in the chemical vapor deposition synthesis of films. The thermodynamic characteristics of the evaporation process were determined. The composition of possible phase complexes and temperature boundaries of their existence in equilibrium with the gas phase were determined by the thermodynamic modeling method. Ethyldi(allylamino)silane can be used to obtain highly transparent films of hydrogenated silicon carbonitride by the plasma-enhanced chemical vapor deposition method.

Thermogravimetry, differential scanning calorimetry, and flow methods were used to investigate thermal properties of a series of cobalt(II) β-iminoketonates [R2C(NR1)CHC(O)R2]. The consecutive order of their volatility was determined. The complexes do not decompose up to melting and do not undergo phase transitions. For the complex (R1 = Н, R2 = Me) the temperature dependence of sublimation ln (p/p0) = 32.02 ‒ 16822/T(K) at 402.6‒433.7 K was measured and the values of ΔsublH°Т* = 140±4 kJ/mol and ΔsublS°Т* = 266±10 J/(K·mol) were calculated.

The crystal structure of new isostructural complex Y(thd)(3) (I), Ho(thd)(3) (II), Tm(thd)(3) (III) and Lu(thd)(3) (IV) are determined: space group Pna2(1), Z = 8 (a = 41.956(8) angstrom, b = 17.837(4) angstrom, c = 9.742(2) angstrom, V = 7291(3) angstrom(3) for I; a = 41.778(2) angstrom, b = 17.8045(6) angstrom, c = 9.6862(3) angstrom, V = 7204.9(4) angstrom(3) for II; a = 41.884(5) angstrom, b = 17.758(2) angstrom, c = 9.672(1) angstrom, V = 7193.7(2) angstrom(3) for III, a = 41.942(8) angstrom, b = 17.712(4) angstrom, c = 9.711(2) angstrom, V = 7214(2) angstrom(3) for IV). The crystal structures of I-IV are molecular and consist of discrete monomeric Ln(thd)(3) molecules (Ln = Y, Ho, Tm, Lu). The highest quantum yields of luminescence are obtained for Tb(thd)(3) (77%), [Tb(thd)(3)](2) (25%) and Dy(thd)(3) (5%), [Dy(thd)(3)](2) (0.4%). Thermogravimetric investigations show that the volatility of complexes increases from Yb(thd)(3) to Pr(thd)(3). Melting points of the complexes are close to the known literature data. The complex compounds we synthesized were characterized by NMR in a CDCl3 solution. Quantum chemical calculations are shown that the phase of dimeric molecules is energetically more stable for the Y(III) complexes with thd-ligands. (C) 2021 Elsevier Ltd. All rights reserved.