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5Т 60 (3)
ИЗВЕСТИЯ ВЫСШИХ УЧЕБНЫХ ЗАВЕДЕНИИ. Серия «ХИМИЯ И ХИМИЧЕСКАЯ ТЕХНОЛОГИЯ»
2017
V 60 (3)
IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA
RUSSIAN JOURNAL OF CHEMISTRY AND CHEMICAL TECHNOLOGY
2017
DOI: 10.6060/tcct.2017603.5601
УДК: 539.27
МОЛЕКУЛЯРНАЯ СТРУКТУРА ТРИС-АЦЕТИЛАЦЕТОНАТА ЖЕЛЕЗА ПО ДАННЫМ МЕТОДА ГАЗОВОЙ ЭЛЕКТРОНОГРАФИИ И КВАНТОВО-ХИМИЧЕСКИХ РАСЧЕТОВ
А.А. Петрова, Н.В. Твердова, Н.И. Гиричева, Г.В. Гиричев
Анжелика Алексеевна Петрова, Наталия Вячеславовна Твердова, Георгий Васильевич Гиричев* Кафедра физики, Ивановский государственный химико-технологический университет, просп. Шереме-тевский, 7, Иваново, Российская Федерация, 153000 E-mail: [email protected], [email protected]*
Нина Ивановна Гиричева
Кафедра органической и физической химии, Ивановский государственный университет, ул. Ермака, 39, Иваново, Российская Федерация, 153025 E-mail: [email protected]
Структура молекулы трис-ацетилацетоната железа, Fe(acac)3, была определена в рамках синхронного электронографического/масс-спектрометрического эксперимента, а также с помощью квантово-химических расчетов методом DFT/UB3LYP/cc-pVTZ. Наилучшее согласие между рассчитанными и экспериментальными функциями интенсивности рассеяния электронов было достигнуто для модели молекулы симметрии D3 с высокоспиновым электронным состоянием. DFTрасчеты также указывают на высокоспиновое электронное состояние 6Al как основное при равновесной геометрической конфигурации молекулы D3 симметрии.
Ключевые слова: трис(ацетилацетонат) железа, спиновое состояние, молекулярная структура, дифракция электронов
UDC: 539.27
MOLECULAR STRUCTURE OF TRIS(ACETYLACETONATE)IRON STUDIED BY GAS-PHASE ELECTRON DIFFRACTION AND DFT CALCULATIONS
A.A. Petrova, N.V. Tverdova, N.I. Giricheva, G.V. Girichev
Angelika A. Petrova, Natalia V. Tverdova, Georgiy V. Girichev*
Department of Physics, Ivanovo State University of Chemistry and Technology, Sheremetevskiy ave., 7,
Ivanovo, Russia, 153000
E-mail: [email protected], [email protected]*
Nina I. Giricheva
Department of Organic and Physical Chemistry, Ivanovo State University, Ermaka str. 39, Ivanovo, Russia, 153025 E-mail: [email protected]
Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3
The molecular structure of tris(acetylacetonate)iron, Fe(O2CH?)3, has been determined by synchronous gas-phase electron diffraction and mass spectrometric experiment along with quantum chemical calculations at the DFT/UB3LYP/cc-pVTZ theory level. The best agreement between theoretical and experimental intensity curves of scattered electrons was obtainedfor the high spin model with the symmetry D3 of molecule. The DFT calculations also resulted in high spin electronic state 6A1 of the molecule Fe(O2CsH7)3 as the ground one at the geometrical configuration of D3 symmetry.
Key words: tris(acetylacetonate)iron, spin state, molecular structure, electron diffraction Для цитирования:
Петрова А. А., Твердова Н.В., Гиричева Н.И. Гиричев Г.В. Молекулярная структура трис-ацетилацетоната железа по данным метода газовой электронографии и квантово-химических расчетов. Изв. вузов. Химия и хим. технология. 2017. Т. 60. Вып. 3. С. 97-99. For citation:
Petrova A.A., Tverdova N.V., Giricheva N.I. Girichev G.V. Molecular structure of tris(acetylacetonate)iron studied by gasphase electron diffraction and DFT calculations. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 97-99.
Experimental studies of the structure of the iron (III) acetylacetonate complex in the gas phase have not been carried out so far. The purpose of this work is to determine the geometric structure of individual molecule Fe(acac)3 by gas-phase electron diffraction supported by DFT calculations. The electron diffraction patterns and the mass spectra of the iron complex were recorded simultaneously using the EMR-100/APDM-1 equipment complex [1] at T=388 (5) K. The mass spectral monitoring of the vapor at this temperature indicates that all the registered ions are formed from a single molecular form of Fe(acac)3.
Table 1
Structural parameters of Fe(acac)3 complex according to electron diffraction (GED) data and DFT calculations Таблица 1. Структурные параметры комплекса Fe(acac)3 согласно электронографическим (GED)
Parameters, À, deg DFT GED
re rh1
Fe-O 2.022 2.018(4)
O-C 1.269 1.268(3)
C-Cr 1.400 1.399(3)
C-Cm 1.508 1.507(3)
Cm-Haver 1.088 1.070(5)
ZOFeO 85.9 87.4(4)
ZCCrC 123.6 123.2(4)
ZFeOC 130.5 129.0(4)
ZOCCm 115.5 115.9(5)
T(HCmCO) 0.6 11(28)
j* 32.0 34.5(11)
Rf , % 5.5
The Fe(acac)3 complex within the framework of the crystal field theory can be represented as consisting of a triple-charged Fe3+ ion (3d5 electron configuration) surrounded by six oxygen atoms of three ligands forming the octahedral symmetry field.
In the case of a weak field, each of the five d-electrons occupies one of the d-AOs of the Fe3+ ion leading to a multiplicity of 6. The calculations DFT/UB3LYP/cc-pVTZ resulted in configuration of D3 symmetry corresponding to the minimum on the PES and electronic state 6Ai (Fig. 1).
Note: * ligand rotation about Fe-C axes from D3h symmetry Примечание: * вращение лиганда вокруг осей Fe-C D3h симметрии
Fig. 1. Molecular structure ofFe(acac)3 with D3 symmetry Рис. 1. Молекулярная структура Fe(acac)3 симметрии D3
98
Изв. вузов. Химия и хим. технология. 2017. Т. 60. Вып. 3
Изв. вузов. Химия и хим. технология. 2017. Т. 60. Вып. 3
Interpretation of the electron diffraction data was carried out for the model of molecule with D3 symmetry, which included 11 independent parameters (Table 1): internuclear distances r(Fe-O), r(O-C), r(C-Cr), r(Cr-H), r(Cm-H), the bond angles ZOFeO, Z FeOC, ZOCCm, ZCCmH and dihedral angles ф (the rotation angle of the ligands around the C2 axis passing through the Fe and Cr atoms, and у (the angle of rotation of the CH3-groups relative to the axis passing through the C and Cm atoms).
The structural parameters of the complex Fe(acac)3, corresponding to the best agreement between the experimental and theoretical curves of the
ЛИТЕРАТУРА
1. Гиричев Г.В., Шлыков С. А., Петрова В.Н., Субботина Н.Ю., Лапшина С.Б., Данилова Т.Г. Аппаратура и методика совместного электронографического и масс-спектрометрического эксперимента и их применение к исследованию молекул тригалогенидов титана. Изв. вузов. Химия и хим. технология. 1988. Т. 31. № 8. С. 46-51.
molecular scattering intensity, are given in Table 1 along with the parameters calculated by the DFT/UB3LYP/cc-pvtz method.
Analysis of Table 1 clearly shows that the geometric model of symmetry D3 is consistent with the results of the electron diffraction experiment. The obtained electron diffraction data do not contradict to the high-spin electronic state of 6A1 as the ground state of the iron tris-acetylacetonate complex in the gas phase under the conditions of the GED experiment.
Acknowledgements. This work was supported by the Russian Foundation for Basic Research (Grant No. 16-03-00855a).
REFERENCES
1. Girichev G.V., Shlykov S.A., Petrova V.N., Subbotina N.Yu., Lapshina S.B., Danilova T.G. Apparatus and technique of a joint electron diffraction and mass spectrometric experiment and their application to the study of molecules of titanium trihalides. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 1988. V. 31. N 8. P. 46-51 (in Russian).
Поступила в редакцию 11.01.2017 Принята к опубликованию 08.02.2017
Received 11.01.2017 Accepted 08.02.2017
