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Magnetic anisotropy of a CoII single ion magnet with distorted trigonal prismatic coordination: theory and experiment

Peng, Yan; Bodenstein, Tilmann; Fink, Karin; Mereacre, Valeriu; Anson, Christopher E.; Powell, Annie K.

Abstract (englisch): The single ion magnetic properties of Co(II) are affected by the details of the coordination geometry of the ion. Here we show that a geometry close to trigonal prismatic which arises when the ligand 6,6′-((1Z)-((piperazine-1,4-diylbis(propane-3,1-diyl))bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol) coordinates to Co(II) does indeed lead to enhanced single-ion behaviour as has previously been predicted. Synthesis of the compound, structural information, and static as well as dynamic magnetic data are presented along with an analysis using quantum chemical ab initio calculations. Though the complex shows a slight deviation from an ideal trigonal prismatic coordination, the zero-field splitting as well as the g-tensor are strongly axial with D = −41 cm−1 and E < 0.01 cm−1. For the lowest Kramers doublet (S = 1/2) g∥ = 7.86 and g⊥ < 0.05 were found. In contrast, the second Kramers doublet possesses a rhombic g-tensor with g∥ = 2.75 and g⊥ = 4.35. Due to large spin–orbit coupling resulting in very different g tensors, it is not possible to simulate the temperature dependence of the magnetic susceptibility with a spin Hamiltonian of the form H = D(Sz2 − S(S + 1)/3) + E(Sx2 − Sy2) + μBgS·B using an effective spin S = 3/2. Calculations on model complexes show the influence of the coordinating atoms and the deviation from the ideal trigonal prismatic coordination. As the distortion is reduced towards idealised D3h, the zero field splitting increases and the g-tensor of the second Kramers doublet also becomes axial.

Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Institut für Anorganische Chemie (AOC)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.1039/C6CP03157A
ISSN: 1463-9076, 1463-9084
URN: urn:nbn:de:swb:90-630734
KITopen ID: 1000063073
HGF-Programm 43.21.04; LK 01
Erschienen in Physical chemistry, chemical physics
Band 18
Heft 43
Seiten 30135–30143
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