title: Magnetic anisotropy of a CoIIsingle ion magnet with distorted trigonal prismatic coordination: theory and experiment.
abstract: 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-1and 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.
authors: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany. annie.powell@kit.edu and Institute of Nanotechnology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany. karin.fink@kit.edu.
authors: Yan
authors: Y
authors: Peng
authors: Institute of Nanotechnology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany. karin.fink@kit.edu and qLEAP Center for Theoretical Chemistry, Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark.
authors: Tilmann
authors: T
authors: Bodenstein
authors: Institute of Nanotechnology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany. karin.fink@kit.edu.
authors: Karin
authors: K
authors: Fink
authors: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany. annie.powell@kit.edu.
authors: Valeriu
authors: V
authors: Mereacre
authors: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany. annie.powell@kit.edu.
authors: Christopher E
authors: CE
authors: Anson
authors: Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany. annie.powell@kit.edu and Institute of Nanotechnology, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany. karin.fink@kit.edu.
authors: Annie K
authors: http://orcid.org/0000-0003-3944-7427
authors: AK
authors: Powell