Ferro- and ferrimagnetic chains ruled by polymorphism in a heptacoordinate manganese(II)-nitronyl-nitroxide-based complex

This work investigates the influence of polymorphism on the magnetic properties of two crystalline forms of a heptacoordinate Mn(II) nitronyl-nitroxide complex. Although both polymorphs share the same molecular structure, differences in crystal packing generate distinct magnetic exchange pathways, resulting in ferromagnetic and ferrimagnetic chain arrangements. Magnetic measurements combined with spin-Hamiltonian modeling and broken-symmetry DFT calculations reveal how subtle structural variations control the magnetic interactions. These results highlight the key role of crystal packing in tuning the magnetic behavior of molecule-based materials and provide valuable insight for the rational design of new molecular magnets.