Journal article
Computational Spectroscopy of the Cr-Cr Bond in Coordination Complexes
Inorganic chemistry, Vol.60(24), pp.19219-19225
12/20/2021
DOI: 10.1021/acs.inorgchem.1c03005
PMID: 34883014
Abstract
We report the accurate computational vibrational analysis of the Cr-Cr bond in dichromium complexes using second-order multireference complete active space methods (CASPT2), allowing direct comparison with experimental spectroscopic data both to facilitate interpreting the low-energy region of the spectra and to provide insights into the nature of the bonds themselves. Recent technological development by the authors has realized such computation for the first time. Accurate simulation of the vibrational structure of these compounds has been hampered by their notorious multiconfigurational electronic structure that yields bond distances that do not correlate with bond order. Some measured Cr-Cr vibrational stretching modes, v(Cr-2), have suggested weaker bonding, even for so-called ultrashort Cr-Cr bonds, while others are in line with the bond distance. Here, we optimize geometries and compute v(Cr-2) with CASPT2 for three well-characterized complexes, Cr-2(O2CCH3)(4) (H2O)(2), Cr-2(mhp)(4), and Cr-2(dmp)(4). We obtain CASPT2 harmonic v(Cr-2) modes in good agreement with experiment at 282 cm(-1) for Cr-2(mhp)(4) and 353 cm(-1) for Cr-2(dmp)(4), compute Cr-50 and Cr-54 isotope shifts, and demonstrate that the use of the so-called IPEA shift leads to improved Cr-Cr distances. Additionally, normal mode sampling was used to estimate anharmonicity along v(Cr-2), leading to an anharmonic mode of 272 cm(-1) for Cr-2(mhp)(4) and 333 cm(-1) for Cr-2(dmp)(4).
Details
- Title: Subtitle
- Computational Spectroscopy of the Cr-Cr Bond in Coordination Complexes
- Creators
- Toru Shiozaki - Simulation Technologies (United States)Bess Vlaisavljevich - University of South Dakota
- Resource Type
- Journal article
- Publication Details
- Inorganic chemistry, Vol.60(24), pp.19219-19225
- DOI
- 10.1021/acs.inorgchem.1c03005
- PMID
- 34883014
- NLM abbreviation
- Inorg Chem
- ISSN
- 0020-1669
- eISSN
- 1520-510X
- Publisher
- Amer Chemical Soc
- Number of pages
- 7
- Grant note
- OAC-1626516 / NSF; National Science Foundation (NSF) DE-SC0019463 / Department of Energy, Office of Science, Basic Energy Sciences; United States Department of Energy (DOE) DE-AC02-05CH11231 / National Energy Research Scientific Computing Center (NERSC), a U.S. Department of Energy Office of Science User Facility
- Language
- English
- Date published
- 12/20/2021
- Academic Unit
- Chemistry
- Record Identifier
- 9984618643602771
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