Issue 12, 2015

Observation of the single-ion magnet behavior of d8 ions on two-coordinate Co(i)–NHC complexes

Abstract

The slow magnetic relaxation typical for single-ion magnets has been known for certain low-coordinate 3d metal complexes with d6, d7, and d9 electronic configurations, but never for d8 complexes. Herein, we report a study on two-coordinate d8 cobalt(I)–N-heterocyclic carbene complexes, for which slow magnetic relaxation behavior was observed for [Co(IMes)2][BPh4] (IMes: 1,3-dimesitylimidazol-2-ylidene) under an applied dc field. The system represents the first d8 single-ion magnet, and features a fitted energy barrier of Ueff = 21.3 cm−1 and pre-exponential factor of τ0 = 6.6 × 10−6 s. The analog two-coordinate cobalt(I) complexes with different NHC ligands, [Co(sIMes)2][BPh4] (sIMes: 1,3-dimesitylimidazolin-2-ylidene) and [Co(IAd)2][BArF4] (IAd: 1,3-dimesitylimidazol-2-ylidene; BArF4: tetra(3,5-ditrifluoromethylphenyl)borate), do not show such single-ion magnet behaviour. Ab initio calculations imply that the dihedral angle between the two NHC planes and the degree of unsaturation of the NHC ligands can dramatically alter the D value of the two-coordinate cobalt(I)–NHC ions, possibly via changing of the Co–NHC π-interactions, and hence affect the spin–orbit coupling splitting.

Graphical abstract: Observation of the single-ion magnet behavior of d8 ions on two-coordinate Co(i)–NHC complexes

Supplementary files

Article information

Article type
Edge Article
Submitted
19 Jul 2015
Accepted
10 Sep 2015
First published
10 Sep 2015
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2015,6, 7156-7162

Observation of the single-ion magnet behavior of d8 ions on two-coordinate Co(I)–NHC complexes

Y. Meng, Z. Mo, B. Wang, Y. Zhang, L. Deng and S. Gao, Chem. Sci., 2015, 6, 7156 DOI: 10.1039/C5SC02611C

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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