Structural and Magnetic Resolution of a Two‐Step Full Spin‐Crossover Transition in a Dinuclear Iron(II) Pyridyl‐Bridged Compound

摘要: A dinuclear iron(II) complex containing the new pyridyl bridging ligand, 2,5-di(2′,2′′-dipyridylamino)pyridine (ddpp) has been synthesised and characterised by single-crystal X-ray diffraction, magnetic susceptibility Mossbauer spectral methods. This compound, [Fe2(ddpp)2(NCS)4]⋅4 CH2Cl2, undergoes a two-step full spin crossover. Structural analysis at each of three plateau temperatures revealed molecule with states HS–HS, HS–LS LS–LS (HS: high spin, LS: low spin) for two centres. is first time that resolution metal centres in ordered state achieved spin-crossover compound. Thermogravimetric data show dichloromethane solvate molecules can be removed distinct steps 120 °C 200 °C. The partially de-solvated clathrate, [Fe2(ddpp)2(NCS)4]⋅CH2Cl2, one-step transition an increased temperature respect to as material. characterisation this material reveals subtle changes coordination geometries striking local environment complex. fully remains over all temperatures. Interestingly, solvent re-introduced into monosolvated solid achieve complete conversion back original crossover material, [Fe2(ddpp)2(NCS)4]⋅4 CH2Cl2.