Synergistic Spin Transition between Spin Crossover and Spin-Peierls-like Singlet Formation in the Halogen-Bonded Molecular Hybrid System: [Fe(Iqsal) sub(2)][Ni(dmit) sub(2)]CH sub(3)CNH sub(2)O

To introduce halogen-bond interactions between a cation and an anion, a novel Fe super(III) complex from iodine-substituted ligands involving a paramagnetic nickel dithiolene anion was prepared and characterized. The compound exhibited the synergy between a spin-crossover transition and a spin-Peierls-like singlet formation. The halogen-bond interactions between the iodine and the sulfur atoms stabilized the paramagnetic state of pi -spins and played a crucial role in the synergistic magnetic transition between d- and pi -spins. In addition, the compound showed the light-induced excited spin state trapping effect.Original Abstract: Ein Fe super(III)-Komplex mit iodsubstituierten Liganden und einem paramagnetischen Nickeldithiolen-Anion als Gegenion zeigt Spin-Crossover und Spin-Peierls-artige Singulettbildung in synergistischer Weise. Die Halogenbruecken zwischen den Iod- und Schwefelatomen stabilisieren den paramagnetischen Zustand der pi -Spins und sind signifikant an dem synergistischen magnetischen Uebergang zwischen d- und pi -Spins beteiligt.