Homoleptic versus Heteroleptic Formation of Mononuclear Fe(II) Complexes with Tris-Imine Ligands

Leoní A. Barrios (1) , Carlos Bartual-Murgui (2, 1) , Eugènia Peyrecave-Lleixà (1) , Boris Le Guennic (3) , Simon J. Teat , Olivier Roubeau (2) , Guillem Aromi (1)

1 Departament de Quimica Inorganica
2 ICMA-CSIC - Instituto de Ciencia de Materiales de Aragón [Saragoza, España]
3 ISCR - Institut des Sciences Chimiques de Rennes

We show a marked tendency of Fe(II) to form heteroleptic [Fe(L)(L')](ClO4)2 complexes from pairs of chelating tris-imine 3bpp, tpy, or 2bbp ligands. New synthetic avenues for spin crossover research become thus available, here illustrated with three new heteroleptic compounds with differing magnetic behaviors: [Fe(H4L1)(Cl-tpy)](ClO4)2·C3H6O (1), [Fe(H2L3)(Me3bpp)](ClO4)2·C3H6O (2), [Fe(H4L1)(2bbp)](ClO4)2·3C3H6O (3). Structural studies demonstrate that 1 is in the low-spin (LS) state up to 350 K, while complexes 2 and 3 are, by contrast, in the high-spin (HS) state down to 2 K, as corroborated through magnetic susceptibility measurements. Upon exposure to the atmosphere, the latter exhibits the release of three molecules of acetone per complex, turning into the solvent-free analogue [Fe(H4L1)(2bbp)](ClO4)2 (3a), through a single-crystal-to-single-crystal transformation. This guest extrusion process is accompanied by a spin switch, from HS to LS

Domaines: Chimie

Leoní A. Barrios, Carlos Bartual-Murgui, Eugènia Peyrecave-Lleixà, Boris Le Guennic, Simon J. Teat, et al.. Homoleptic versus Heteroleptic Formation of Mononuclear Fe(II) Complexes with Tris-Imine Ligands. Inorganic Chemistry, 2016, 55 (9), pp.4110-4116. ⟨10.1021/acs.inorgchem.5b02058⟩. ⟨hal-01304298⟩