TY - JOUR

T1 - Thermochemical study of fluorinated magnesium BETA-DIKETONATE complexes: development of a promising class of volatile MOCVD precursors

AU - Zelenina, L. N.

AU - Nazarova, A. A.

AU - Vikulova, E. S.

AU - Макаренко, Александр Михайлович

AU - Урбах, Алина Андреевна

AU - Гельфонд, Н. В.

N1 - The static and DSC studies were carried out with the support of the Ministry of Science and Higher Education of the Russian Federation (project No. 125021001790-0). Measurements of vapor pressure using the transpiration method were carried out with financial support from the Russian Science Foundation (project number 24-79-10272, https://rscf.ru/project/24-79-10272).

PY - 2026/7

Y1 - 2026/7

N2 - Heteroligand fluorinated magnesium beta-diketonate complexes are favorable precursors for metal-organic chemical vapor deposition (MOCVD) due to their availability, stability, high volatility and versatility for producing both oxide and fluoride films. Quantitative and reliable thermal data for these compounds are needed both to design of new effective precursors and to optimize the vaporization conditions precisely. Therefore, a thermochemical study of two complexes of this type, Mg(tmeda)(hfac)2 and Mg(tmeda)(ptac)2 (tmeda = N , N , N ′, N -tetramethylethylenediamine, hfac = hexafluoroacetylacetonate, ptac = pivaloyltrifluoroacetonate), has been carried out for the first time. The thermal behavior of the complexes in the condensed phase was investigated by differential scanning calorimetry and the thermodynamic parameters of phase transitions ( T tr, Δtr H °T tr) were determined. The pressure of the saturated and unsaturated vapors of the complexes has been measured by the static method with a membrane-gauge manometer and a transpiration method in a wide interval of temperatures: 348–524 K for Mg(tmeda)(ptac)2 and 323–492 K for Mg(tmeda)(hfac)2. As a result of this study the thermal stability of compounds under study was established and based on the data on unsaturated vapors, it was concluded that both complexes pass into the gas phase in the form of a monomer. Equations approximating the dependences of saturated vapor pressure on temperature and also the enthalpies and entropies of sublimation (Δsub H °T, Δsub S °T) and vaporization (Δvap H °T, Δvap S °T) were determined from the experimental data. All thermodynamic values were obtained for the first time. In addition, thermodynamic simulation of MOCVD processes with the participation of the studied complexes as precursors was performed to provide a basis for selecting the conditions for the formation of MgF2 and MgO films using O2 and O2/H2O as co-reagents.

AB - Heteroligand fluorinated magnesium beta-diketonate complexes are favorable precursors for metal-organic chemical vapor deposition (MOCVD) due to their availability, stability, high volatility and versatility for producing both oxide and fluoride films. Quantitative and reliable thermal data for these compounds are needed both to design of new effective precursors and to optimize the vaporization conditions precisely. Therefore, a thermochemical study of two complexes of this type, Mg(tmeda)(hfac)2 and Mg(tmeda)(ptac)2 (tmeda = N , N , N ′, N -tetramethylethylenediamine, hfac = hexafluoroacetylacetonate, ptac = pivaloyltrifluoroacetonate), has been carried out for the first time. The thermal behavior of the complexes in the condensed phase was investigated by differential scanning calorimetry and the thermodynamic parameters of phase transitions ( T tr, Δtr H °T tr) were determined. The pressure of the saturated and unsaturated vapors of the complexes has been measured by the static method with a membrane-gauge manometer and a transpiration method in a wide interval of temperatures: 348–524 K for Mg(tmeda)(ptac)2 and 323–492 K for Mg(tmeda)(hfac)2. As a result of this study the thermal stability of compounds under study was established and based on the data on unsaturated vapors, it was concluded that both complexes pass into the gas phase in the form of a monomer. Equations approximating the dependences of saturated vapor pressure on temperature and also the enthalpies and entropies of sublimation (Δsub H °T, Δsub S °T) and vaporization (Δvap H °T, Δvap S °T) were determined from the experimental data. All thermodynamic values were obtained for the first time. In addition, thermodynamic simulation of MOCVD processes with the participation of the studied complexes as precursors was performed to provide a basis for selecting the conditions for the formation of MgF2 and MgO films using O2 and O2/H2O as co-reagents.

KW - DSC

KW - Magnesium beta-diketonates

KW - Melting and evaporation processes

KW - Static method with glass membrane gauge-manometer

KW - Thermodynamic characteristics

KW - Thermodynamic simulation

KW - Vapor pressure

UR - https://www.scopus.com/pages/publications/105031897303

UR - https://www.mendeley.com/catalogue/13dcabd3-5eca-32a5-b1f8-388f70096e4b/

U2 - 10.1016/j.jct.2026.107659

DO - 10.1016/j.jct.2026.107659

M3 - Article

VL - 216

JO - Journal of Chemical Thermodynamics

JF - Journal of Chemical Thermodynamics

SN - 0021-9614

M1 - 107659

ER -