Electronic Structure and Magnetic Properties of a Low-Spin CrIIComplex: Trans-[CrCl2(dmpe)2] (dmpe = 1,2-Bis(dimethylphosphino)ethane)

Zolnhofer E, Opalade AA, Jackson TA, Heinemann FW, Meyer K, Krzystek J, Ozarowski A, Telser J (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Inorganic Chemistry American Chemical Society

DOI: 10.1021/acs.inorgchem.1c02471

Abstract

Octahedral coordination complexes of the general formula trans-[MX2(R2ECH2CH2ER2)2] (MII = Ti, V, Cr, Mn; E = N, P; R = alkyl, aryl) are a cornerstone of both coordination and organometallic chemistry, and many of these complexes are known to have unique electronic structures that have been incompletely examined. The trans-[CrCl2(dmpe)2] complex (dmpe = Me2PCH2CH2PMe2), originally reported by Girolami and co-workers in 1985, is a rare example of a six-coordinate d4 system with an S = 1 (spin triplet) ground state, as opposed to the high-spin (S = 2, spin quintet) state. The ground-state properties of S = 1 systems are challenging to study using conventional spectroscopic methods, and consequently, the electronic structure of trans-[CrCl2(dmpe)2] has remained largely unexplored. In this present work, we have employed high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy to characterize the ground-state electronic structure of trans-[CrCl2(dmpe)2]. This analysis yielded a complete set of spin Hamiltonian parameters for this S = 1 complex: D = +7.39(1) cm-1, E = +0.093(1) (E/D = 0.012), and g = [1.999(5), 2.00(1), 2.00(1)]. To develop a detailed electronic structure description for trans-[CrCl2(dmpe)2], we employed both classical ligand-field theory and quantum chemical theory (QCT) calculations, which considered all quintet, triplet, and singlet ligand-field states. While the high density of states suggests an unexpectedly complex electronic structure for this "simple"coordination complex, both the ligand-field and QCT methods were able to reproduce the experimental spin Hamiltonian parameters quite nicely. The QCT computations were also used as a basis for assigning the electronic absorption spectrum of trans-[CrCl2(dmpe)2] in toluene.

Authors with CRIS profile

Eva Zolnhofer Lehrstuhl für Anorganische und Allgemeine Chemie Frank Wilhelm Heinemann Lehrstuhl für Anorganische und Allgemeine Chemie Karsten Meyer Lehrstuhl für Anorganische und Allgemeine Chemie

Involved external institutions

University of Kansas (KU) US United States (USA) (US) Florida State University (FSU) US United States (USA) (US) Roosevelt University US United States (USA) (US)

How to cite

APA:

Zolnhofer, E., Opalade, A.A., Jackson, T.A., Heinemann, F.W., Meyer, K., Krzystek, J.,... Telser, J. (2021). Electronic Structure and Magnetic Properties of a Low-Spin CrIIComplex: Trans-[CrCl2(dmpe)2] (dmpe = 1,2-Bis(dimethylphosphino)ethane). Inorganic Chemistry. https://dx.doi.org/10.1021/acs.inorgchem.1c02471

MLA:

Zolnhofer, Eva, et al. "Electronic Structure and Magnetic Properties of a Low-Spin CrIIComplex: Trans-[CrCl2(dmpe)2] (dmpe = 1,2-Bis(dimethylphosphino)ethane)." Inorganic Chemistry (2021).

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