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Polymorphism in the spin-crossover ferric complexes [(TPA)Fe III (TCC)]PF 6

2009; Wiley; Volume: 65; Issue: 4 Linguagem: Inglês

10.1107/s0108768109021508

1600-5740

Éric Collet, M.-L. Boillot, Johan Hébert, N. Moisan, Marina Servol, Maciej Lorenc, Loïc Toupet, Marylise Buron‐Le Cointe, Antoine Tissot, J. Sainton,

Electron Spin Resonance Studies

We have identified two polymorphs of the molecular complex [(TPA)Fe (III) (TCC)]PF 6 [TPA = tris(2-pyridylmethyl)amine and TCC = 3,4,5,6-tetrachlorocatecholate dianion]: one is monoclinic and the other is orthorhombic. By lowering the temperature both undergo a thermal spin-crossover between a high-spin ( S = 5/2) and a low-spin ( S = 1/2) state, which we detected by magnetic, optical and X-ray diffraction measurements. The thermal crossover is only slightly shifted between the polymorphs. Their crystalline structures consist of similar cation layers alternating with PF 6 anion layers, packed differently in the two polymorphs. The magnetic and optical properties of the polymorphs are presented.