Anionic Tuning of Spin Crossover in Fe-III-Quinolylsalicylaldiminate Complexes

作者：Sertphon Darunee; Harding David J^*; Harding Phimphaka; Murray Keith S; Moubaraki Boujemaa; Cashion John D; Adams Harry

来源：European Journal of Inorganic Chemistry, 2013, 2013(5-6): 788-795.

DOI：10.1002/ejic.201201066

• Spin crossover
• Iron
• X-ray diffraction
• Magnetic properties
• Mossbauer spectroscopy

A series of Fe-III complexes, [Fe(qsal-5-OMe)(2)]Y [Y = BF4 (1), PF6 (2), NCS (3), BPh4 (4)], have been prepared and structurally and magnetically characterized. The low-temperature structures of 1 and 3 as solvent adducts were determined by X-ray crystallography with LS Fe-III centres found in both cases. pi-pi and C-H center dot center dot center dot pi interactions between the cations lead to 2D sheets that are linked to one another through C-H center dot center dot center dot O and, in the case of 3, C-H center dot center dot center dot N/S interactions resulting in high cooperativity. Magnetic studies revealed abrupt and gradual spin crossover for 3 and 2, respectively. For 3, spin crossover with possible thermal hysteresis was observed although solvent loss (CH2Cl2) could occur. In contrast, 1 and 4 were found to be low and high spin only, respectively. The results of Mossbauer spectroscopic studies are consistent with the magnetic susceptibility data and indicate that there are two low-spin Fe-III centres in 2. Finally, electrochemical studies showed reversible reduction to Fe-II at 0.22 V, whereas reversible oxidation of the qsal-5-OMe ligand was found to occur between 1.04-1.06 V.

• 出版日期2013-2