Ferromagnetic exchange coupling in a spiro-fused dinuclear nickel(II) complex with an approximate D2d symmetry

Ferromagnetic exchange coupling was operative between nickel(II) spins in a dinuclear nickel(II) complex [{Ni(hfac)2}2(py4C)] owing to the orthogonal arrangement of the magnetic orbitals (py4C = tetrakis(2-pyridyl)methane).