Orthogonal magnetic orbit-als in high spin Cu-VO units: structure, mag-netism and EPR study of aniso-tropic hetero-metallic com-plexes

Abstract

Molecular-based magnetic materials are expected to serve as building blocks for quantum bits. To realize high-dimensional Hilbert space and addressability, we constructed anisotropic multi-level systems based on CuII and VIV with orthogonal magnetic orbitals. The crystal structures and intramolecular magnetic cou-plings of four CuIIVOII com-plexes [{CuVO(appen)2}2], [{CuVO(fhma)2EDA}2], [{Cu-VO(hfca)2EDA}2] and [Cu-VO(hfca)2DPEDA]n are charac-terized. Due to the orthogonal magnetic orbitals of CuII and VIV, the Cu-V pairs in the four complexes have strong ferro-magnetic couplings, and the coupling strength is linearly related to the dihedral angle between the two equatorial planes of the two coordination polyhedra. Because of the triplet ground state, the sys-tem can be described by an effective Hamiltonian model consisting of two S = 1 spins coupled, the anisotropy pa-rameters of [{Cu-VO(hfca)2EDA}2] and [Cu-VO(hfca)2DPEDA]n were ob-tained by the simulation of X-band continuous wave elec-tron paramagnetic resonance (cw-EPR) spectra, confirming that both complexes have zero-field splitting addressable on the relative energy scale. The results indicate that con-structing multi-centre com-plexes based on orthogonal magnetic orbitals makes a promising strategy for design-ing multidimensional quantum bits.