Thermodynamic study of sublimation, melting and vaporization of scandium(III) dipivaloylmethanate derivatives

Metal-Organic Chemical Vapor Deposition Precursors: Diagnostic Check for Volatilization Thermodynamics of Scandium(III) β-Diketonates

“…The synthesis and characterization (CHF-analysis, 1 H NMR spectroscopy, X-ray diffraction analysis, melting point etc.) of the complexes were described in detail in our previous articles [14,31,32]. Before the start of the experiment, the compounds were subjected to additional purification by sublimation in a vacuum gradient furnace at a residual pressure of 1.33 Pa and temperatures of 318-453 K. During the transpiration experiment, elemental analyses of complex collected in the trap were also carried out to confirm the purity of the compound and reveal the absence of decomposition.…”

“…The mass loss rates dm•dt −1 for Sc(acac) 3 measured at different temperatures are given in Table S2. To date, sublimation and vaporization enthalpies are available for seven scandium(III) β-diketonates [6][7][8][9][10][11][12][13][14]32,40,[45][46][47][48][49][50]; the relevant literature data are compiled for evaluation together with the data obtained in this work (Table 2). Almost all crystal-gas and liquid-gas phase transition enthalpies have been derived from p-T measurements by using different methods also indicated in Table 2.…”

“…Since the required ∆ g cr,l C o p,m values were absent in the past, the first correct comparison of the available sublimation/vaporization enthalpies of the tris(β-diketonato)scandium(III) complexes has been performed (see Table 2) using the heat capacity differences given in Table S4. If the primary experimental vapor pressure data are available in the literature [11,14,32,48], we have treated them uniformly by using Equations ( 5) and (6). In cases, where only the ∆ g cr,l H o m (T) values are reported, we used Equations ( 13) or (14) to adjust these values to the reference temperature T = 298.15 K. The ∆ g cr,l H o m (298.15 K) values are provided by combined uncertainties including uncertainties associated with the experimental vapor pressure measurement conditions and temperature adjustment to T = 298.15 K as described elsewhere [37].…”