Periodic trends for transition metal dihydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}xH{sub 2}, and tetrahydrides MH{sub 4} (M = Ti, V, and Cr)

Ma, B; Collins, L C; Schaefer, III, H F

doi:10.1021/ja951376t

Title: Periodic trends for transition metal dihydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}xH{sub 2}, and tetrahydrides MH{sub 4} (M = Ti, V, and Cr)

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Abstract

Ab initio quantum mechanical methods were employed to study the periodic trends of transition metal (M = Ti, V, and Cr) hydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}.H{sub 2}, and tetrahydrides MH{sub 4}. All three MH{sub 2}.H{sub 2} complexes are in the high-spin ground state. The low-spin dihydrides interact with the H{sub 2} moiety more strongly than do the high-spin species. The d {yields} {sigma}{sup *} back donation was so strong for the low-spin TiH{sub 2} that H{sub 2} dissociates without barrier upon contact with singlet TiH{sub 2} to form TiH{sub 4}. Due to the Jahn-Teller distortion the ground state of VH{sub 4} is the {sup 2}A{sub 1} electronic state having D{sub 2d} symmetry. TiH{sub 4} is predicted to lie 9 kcal mol{sup -1} lower in energy than its ground state MH{sub 2}.H{sub 2} isomer, whereas VH{sub 4} and CrH{sub 4} are higher in energy by 22 and 39 kcal mol{sup -1}, respectively, at the TZP CCSD level of theory. However, comparing MH{sub 4} and MH{sub 2}.H{sub 2} in the same spin state, MH{sub 4} is always lower in energy than its dihydrogen complex isomer, MH{sub 2}.H{sub 2}, on the low-spin potential energy surface. Comparison between the present workmore »« less

Authors:

Ma, B; Collins, L C; Schaefer, III, H F ^[1]

Univ. of Georgia, Athens, GA (United States)

Publication Date:: Wed Jan 31 00:00:00 EST 1996

OSTI Identifier:: 232490

DOE Contract Number:: FG09-87ER13811

Resource Type:: Journal Article

Journal Name:: Journal of the American Chemical Society

Additional Journal Information:: Journal Volume: 118; Journal Issue: 4; Other Information: PBD: 31 Jan 1996

Country of Publication:: United States

Language:: English

Subject:: 40 CHEMISTRY; 66 PHYSICS; HYDRIDES; CONFIGURATION INTERACTION; TITANIUM HYDRIDES; VANADIUM HYDRIDES; CHROMIUM HYDRIDES; CALCULATION METHODS; ENERGY LEVELS; GROUND STATES; JAHN-TELLER EFFECT; INFRARED SPECTRA; ELECTRONIC STRUCTURE; VIBRATIONAL STATES; EXPERIMENTAL DATA

Citation Formats


                    Ma, B, Collins, L C, and Schaefer, III, H F. Periodic trends for transition metal dihydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}xH{sub 2}, and tetrahydrides MH{sub 4} (M = Ti, V, and Cr).  United States: N. p., 1996. 
        Web.  doi:10.1021/ja951376t.

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                    Ma, B, Collins, L C, & Schaefer, III, H F. Periodic trends for transition metal dihydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}xH{sub 2}, and tetrahydrides MH{sub 4} (M = Ti, V, and Cr).  United States.  https://doi.org/10.1021/ja951376t

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                    Ma, B, Collins, L C, and Schaefer, III, H F. 1996.  
        "Periodic trends for transition metal dihydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}xH{sub 2}, and tetrahydrides MH{sub 4} (M = Ti, V, and Cr)".  United States.  https://doi.org/10.1021/ja951376t.

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@article{osti_232490,

  title        = {Periodic trends for transition metal dihydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}xH{sub 2}, and tetrahydrides MH{sub 4} (M = Ti, V, and Cr)},

  author       = {Ma, B and Collins, L C and Schaefer, III, H F},

  abstractNote = {Ab initio quantum mechanical methods were employed to study the periodic trends of transition metal (M = Ti, V, and Cr) hydrides MH{sub 2}, dihydride dihydrogen complexes MH{sub 2}.H{sub 2}, and tetrahydrides MH{sub 4}. All three MH{sub 2}.H{sub 2} complexes are in the high-spin ground state. The low-spin dihydrides interact with the H{sub 2} moiety more strongly than do the high-spin species. The d {yields} {sigma}{sup *} back donation was so strong for the low-spin TiH{sub 2} that H{sub 2} dissociates without barrier upon contact with singlet TiH{sub 2} to form TiH{sub 4}. Due to the Jahn-Teller distortion the ground state of VH{sub 4} is the {sup 2}A{sub 1} electronic state having D{sub 2d} symmetry. TiH{sub 4} is predicted to lie 9 kcal mol{sup -1} lower in energy than its ground state MH{sub 2}.H{sub 2} isomer, whereas VH{sub 4} and CrH{sub 4} are higher in energy by 22 and 39 kcal mol{sup -1}, respectively, at the TZP CCSD level of theory. However, comparing MH{sub 4} and MH{sub 2}.H{sub 2} in the same spin state, MH{sub 4} is always lower in energy than its dihydrogen complex isomer, MH{sub 2}.H{sub 2}, on the low-spin potential energy surface. Comparison between the present work and experimental IR spectra from the matrix isolation of the cocondensation of transition metal atoms (Ti, V, and Cr) with H{sub 2} molecules confirmed the existence of CrH{sub 2}.H{sub 2} by identifying a strong unique absorption at 1510 cm{sup -1}. 17 refs., 4 figs., 8 tabs.},

  doi          = {10.1021/ja951376t},

  url          = {https://www.osti.gov/biblio/232490},
  journal      = {Journal of the American Chemical Society},
number       = 4,

  volume       = 118,

  place        = {United States},

  year         = {Wed Jan 31 00:00:00 EST 1996},

  month        = {Wed Jan 31 00:00:00 EST 1996}

}

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