Structure and Magnetic Properties of the Spin Crossover Linear Trinuclear Complex [Fe 3 (furtrz) 6 (ptol) 2 (MeOH) 4 ]·4(ptol)·4(MeOH) (furtrz: furanylidene-4H-1,2,4-triazol-4-amine ptol: p -tolylsulfonate)

摘要

The furan-functionalised 1,2,4-triazole ligand furanylidene-4H-1,2,4-triazol-4-amine (furtrz) has been incorporated into the trinuclear complex Fe 3 (furtrz) 6 (ptol) 2 (MeOH) 4 ]·4(ptol)·4(MeOH) (ptol = p -tolylsulfonate) composed of μ 1,2 -triazole bridges between iron(II) sites, as per one-dimensional chain materials, and terminally coordinated ptol anions and methanol molecules. Magnetic susceptibility measurements reveal a gradual single-step spin crossover (SCO) behavior of one third of the iron(II) sites per trinuclear unit. Single-crystal X-ray diffraction below the transition (90 K) shows the central iron(II) sites undergo a HS to LS transition and the peripheral ones remain HS (HS = high spin; LS = low spin). This is a rare example of a cationic trinuclear SCO material where the discrete unit includes bound anions.