Microwave measurements and calculations on the molecular structure of tetracarbonyldihydroruthenium

T. Greg Lavaty, Pollyanna Wikrent, Brian J. Drouin, Stephen G Kukolich

Research output: Contribution to journalArticle

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Abstract

The microwave rotational spectra for seven isotopomers of tetracarbonyldihydroruthenium were measured in the 4-12 GHz range using a Flygare-Balle type microwave spectrometer. The measured transition frequencies could be fit to within a few kilohertz using a rigid rotor Hamiltonian with centrifugal distortion. The rotational constants for the most abundant isotopomer are A=1234.2762(4), B=932.7016(6), and C=811.6849(6)MHz. The dipole moment is aligned with the c axis of the complex. The 21 measured rotational constants were used to determine the following structural parameters: r(Ru-H)=1.710(23)Å, r(Ru-C1)=1.952(21)Å, r(Ru-C3)=1.974(28)Å, (H-Ru-H)=87.4(2.4)°, (C1-Ru-C2)=160.6(4.3)°, (C3-Ru-C4)=101.4(1.5)°, and (Ru-C1-O1)=172.6(7.6)°. The axial carbonyl groups are bent slightly toward the hydrogen atoms. These structural parameters are in excellent agreement with the substitution coordinates determined from the Kraitchman equations, and with the structural parameters calculated using density functional theory. There was no previous structural data on this complex. The results of the microwave data and theoretical calculations both indicate C2v molecular symmetry, and show that the H atoms are separated by about 2.36 Å. These results indicate that this complex is clearly a "classical dihydride" rather than an η2-bonded, "dihydrogen" complex. Fairly large deuterium isotope effects were observed for the Ru-H bond length and H-Ru-H angle. The r0, Ru-D bond lengths were observed to be 0.03(2) Å shorter than the r0, Ru-H bond lengths. The D-Ru-D angle is 1.1° less than the H-Ru-H angle indicating that the anharmonicity effects are comparable for the bond lengths and for the interbond angle. The new results on this complex are compared with previous results on the similar dihydride complexes, H2Fe(CO)4, and H2Os(CO)4.

Original languageEnglish (US)
Pages (from-to)9473-9478
Number of pages6
JournalThe Journal of Chemical Physics
Volume109
Issue number21
DOIs
StatePublished - 1998

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Microwave measurement
Bond length
Molecular structure
molecular structure
microwaves
dihydrides
Carbon Monoxide
Microwave spectrometers
Microwaves
Rigid rotors
microwave spectrometers
Hamiltonians
Atoms
rigid rotors
Deuterium
Dipole moment
microwave spectra
rotational spectra
Isotopes
isotope effect

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Microwave measurements and calculations on the molecular structure of tetracarbonyldihydroruthenium. / Lavaty, T. Greg; Wikrent, Pollyanna; Drouin, Brian J.; Kukolich, Stephen G.

In: The Journal of Chemical Physics, Vol. 109, No. 21, 1998, p. 9473-9478.

Research output: Contribution to journalArticle

Lavaty, T. Greg ; Wikrent, Pollyanna ; Drouin, Brian J. ; Kukolich, Stephen G. / Microwave measurements and calculations on the molecular structure of tetracarbonyldihydroruthenium. In: The Journal of Chemical Physics. 1998 ; Vol. 109, No. 21. pp. 9473-9478.
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title = "Microwave measurements and calculations on the molecular structure of tetracarbonyldihydroruthenium",
abstract = "The microwave rotational spectra for seven isotopomers of tetracarbonyldihydroruthenium were measured in the 4-12 GHz range using a Flygare-Balle type microwave spectrometer. The measured transition frequencies could be fit to within a few kilohertz using a rigid rotor Hamiltonian with centrifugal distortion. The rotational constants for the most abundant isotopomer are A=1234.2762(4), B=932.7016(6), and C=811.6849(6)MHz. The dipole moment is aligned with the c axis of the complex. The 21 measured rotational constants were used to determine the following structural parameters: r(Ru-H)=1.710(23){\AA}, r(Ru-C1)=1.952(21){\AA}, r(Ru-C3)=1.974(28){\AA}, (H-Ru-H)=87.4(2.4)°, (C1-Ru-C2)=160.6(4.3)°, (C3-Ru-C4)=101.4(1.5)°, and (Ru-C1-O1)=172.6(7.6)°. The axial carbonyl groups are bent slightly toward the hydrogen atoms. These structural parameters are in excellent agreement with the substitution coordinates determined from the Kraitchman equations, and with the structural parameters calculated using density functional theory. There was no previous structural data on this complex. The results of the microwave data and theoretical calculations both indicate C2v molecular symmetry, and show that the H atoms are separated by about 2.36 {\AA}. These results indicate that this complex is clearly a {"}classical dihydride{"} rather than an η2-bonded, {"}dihydrogen{"} complex. Fairly large deuterium isotope effects were observed for the Ru-H bond length and H-Ru-H angle. The r0, Ru-D bond lengths were observed to be 0.03(2) {\AA} shorter than the r0, Ru-H bond lengths. The D-Ru-D angle is 1.1° less than the H-Ru-H angle indicating that the anharmonicity effects are comparable for the bond lengths and for the interbond angle. The new results on this complex are compared with previous results on the similar dihydride complexes, H2Fe(CO)4, and H2Os(CO)4.",
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T1 - Microwave measurements and calculations on the molecular structure of tetracarbonyldihydroruthenium

AU - Lavaty, T. Greg

AU - Wikrent, Pollyanna

AU - Drouin, Brian J.

AU - Kukolich, Stephen G

PY - 1998

Y1 - 1998

N2 - The microwave rotational spectra for seven isotopomers of tetracarbonyldihydroruthenium were measured in the 4-12 GHz range using a Flygare-Balle type microwave spectrometer. The measured transition frequencies could be fit to within a few kilohertz using a rigid rotor Hamiltonian with centrifugal distortion. The rotational constants for the most abundant isotopomer are A=1234.2762(4), B=932.7016(6), and C=811.6849(6)MHz. The dipole moment is aligned with the c axis of the complex. The 21 measured rotational constants were used to determine the following structural parameters: r(Ru-H)=1.710(23)Å, r(Ru-C1)=1.952(21)Å, r(Ru-C3)=1.974(28)Å, (H-Ru-H)=87.4(2.4)°, (C1-Ru-C2)=160.6(4.3)°, (C3-Ru-C4)=101.4(1.5)°, and (Ru-C1-O1)=172.6(7.6)°. The axial carbonyl groups are bent slightly toward the hydrogen atoms. These structural parameters are in excellent agreement with the substitution coordinates determined from the Kraitchman equations, and with the structural parameters calculated using density functional theory. There was no previous structural data on this complex. The results of the microwave data and theoretical calculations both indicate C2v molecular symmetry, and show that the H atoms are separated by about 2.36 Å. These results indicate that this complex is clearly a "classical dihydride" rather than an η2-bonded, "dihydrogen" complex. Fairly large deuterium isotope effects were observed for the Ru-H bond length and H-Ru-H angle. The r0, Ru-D bond lengths were observed to be 0.03(2) Å shorter than the r0, Ru-H bond lengths. The D-Ru-D angle is 1.1° less than the H-Ru-H angle indicating that the anharmonicity effects are comparable for the bond lengths and for the interbond angle. The new results on this complex are compared with previous results on the similar dihydride complexes, H2Fe(CO)4, and H2Os(CO)4.

AB - The microwave rotational spectra for seven isotopomers of tetracarbonyldihydroruthenium were measured in the 4-12 GHz range using a Flygare-Balle type microwave spectrometer. The measured transition frequencies could be fit to within a few kilohertz using a rigid rotor Hamiltonian with centrifugal distortion. The rotational constants for the most abundant isotopomer are A=1234.2762(4), B=932.7016(6), and C=811.6849(6)MHz. The dipole moment is aligned with the c axis of the complex. The 21 measured rotational constants were used to determine the following structural parameters: r(Ru-H)=1.710(23)Å, r(Ru-C1)=1.952(21)Å, r(Ru-C3)=1.974(28)Å, (H-Ru-H)=87.4(2.4)°, (C1-Ru-C2)=160.6(4.3)°, (C3-Ru-C4)=101.4(1.5)°, and (Ru-C1-O1)=172.6(7.6)°. The axial carbonyl groups are bent slightly toward the hydrogen atoms. These structural parameters are in excellent agreement with the substitution coordinates determined from the Kraitchman equations, and with the structural parameters calculated using density functional theory. There was no previous structural data on this complex. The results of the microwave data and theoretical calculations both indicate C2v molecular symmetry, and show that the H atoms are separated by about 2.36 Å. These results indicate that this complex is clearly a "classical dihydride" rather than an η2-bonded, "dihydrogen" complex. Fairly large deuterium isotope effects were observed for the Ru-H bond length and H-Ru-H angle. The r0, Ru-D bond lengths were observed to be 0.03(2) Å shorter than the r0, Ru-H bond lengths. The D-Ru-D angle is 1.1° less than the H-Ru-H angle indicating that the anharmonicity effects are comparable for the bond lengths and for the interbond angle. The new results on this complex are compared with previous results on the similar dihydride complexes, H2Fe(CO)4, and H2Os(CO)4.

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