TY - JOUR

T1 - Structure and Thermal Properties of Tris-(methylcyclopentadienyl)Scandium

AU - Petukhova, D. E.

AU - Sartakova, A. V.

AU - Sukhikh, T. S.

AU - Afonin, M. Y.

AU - Sysoev, S. V.

AU - Vikulova, E. S.

N1 - This work was funded by the Ministry of Science and Higher Education of the Russian Federation, State Assignment No. 122111500007-6. Публикация для корректировки.

PY - 2023/12

Y1 - 2023/12

N2 - 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 C2/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) Å3, Z = 8, D calc = 1.217 g/cm3. 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(η5-MeCp)2(η1-MeCp) structure with Sc–Z distances equal to 2.26-2.37 Å, where Z is the center of the η5-MeCp species or the C atom (for η1-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: Δev H 0(458.5) = 82.5±1.1 kJ/mol, Δev S 0(458.5) = 135±2 J/(mol·K).

AB - 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 C2/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) Å3, Z = 8, D calc = 1.217 g/cm3. 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(η5-MeCp)2(η1-MeCp) structure with Sc–Z distances equal to 2.26-2.37 Å, where Z is the center of the η5-MeCp species or the C atom (for η1-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: Δev H 0(458.5) = 82.5±1.1 kJ/mol, Δev S 0(458.5) = 135±2 J/(mol·K).

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85180898530&origin=inward&txGid=c5b7f69c46f48df05e22dd4e249b1cb5

UR - https://www.mendeley.com/catalogue/ecb4a03d-c496-3210-be32-572fdbed2975/

U2 - 10.1134/s002247662312017x

DO - 10.1134/s002247662312017x

M3 - Article

VL - 64

SP - 2461

EP - 2471

JO - Journal of Structural Chemistry

JF - Journal of Structural Chemistry

SN - 0022-4766

IS - 12

ER -