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Electronic Structure of Tetracyanonickelate(II)

Oppenheim, Julius J. and McNicholas, Brendon J. and Miller, Jayce and Gray, Harry B. (2019) Electronic Structure of Tetracyanonickelate(II). Inorganic Chemistry, 58 (22). pp. 15202-15206. ISSN 0020-1669. doi:10.1021/acs.inorgchem.9b02135.

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Tetracyanonickelate(II) has been a poster child of ligand field theory for several decades. We have revisited the literature assignments of the absorption spectrum of [Ni(CN) ₄]²⁻ and the calculated ordering of orbitals with metal d character. Using low-temperature single-crystal absorption spectroscopy and accurate ab initio and density functional quantum mechanical methods (NEVPT2-CASSCF, EOM-CCSD, TD-DFT), we find an ordering of the frontier d- and p-orbitals of xy < xz, yz < z² < z < x²–y² < x, y and assign the d-d bands in the absorption spectrum to ¹A_(1g) → ³B_(1g) < ³E_g < ³A_(2g) < ¹B_(1g) < ¹E_g < ¹A_(2g). While differing from all previous interpretations, our assignments accord with an MO model in which strong π-backbonding in the plane of the molecule stabilizes d_(xy) more than out-of-plane bonding stabilizes d_(xz) and d_(yz).

Item Type:Article
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URLURL TypeDescription
Oppenheim, Julius J.0000-0002-5988-0677
McNicholas, Brendon J.0000-0002-3654-681X
Gray, Harry B.0000-0002-7937-7876
Additional Information:© 2019 American Chemical Society. Received: July 17, 2019; Published: November 7, 2019. Time on a computing cluster was provided by the Beckman Institute Materials and Process Simulation Center; absorption spectroscopy was performed in the BI Laser Center (with assistance from Jay Winkler). We thank Garnet Chan, Daniel Weitekamp, Thomas Gallup, Christopher Lamartina, Jonathan Chan, and Kaitlyn Takata for helpful discussions. Our work was supported by NSF CHE-1763429. The authors also appreciate and acknowledge a quote given in a lecture at the ICCC meeting in Vienna in 1964 by one of the authors of this paper (H.B.G.), where he announced: “As there are so many square planar d-orbital energy orderings in the literature, one must be correct, so all we need to do is to find who found it!” The authors declare no competing financial interest.
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Issue or Number:22
Record Number:CaltechAUTHORS:20191107-105330295
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Official Citation:Electronic Structure of Tetracyanonickelate(II). Julius J. Oppenheim, Brendon J. McNicholas, Jayce Miller, and Harry B. Gray. Inorganic Chemistry 2019 58 (22), 15202-15206 DOI: 10.1021/acs.inorgchem.9b02135
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99736
Deposited By: Tony Diaz
Deposited On:07 Nov 2019 19:00
Last Modified:16 Nov 2021 17:48

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