Anionic Tuning of Spin Crossover in FeIII–Quinolylsalicylaldiminate Complexes. Issue 5 (26th November 2012)

• Record Type: Journal Article
• Authors: Sertphon, Darunee; Harding, David J.; Harding, Phimphaka; Murray, Keith S.; Moubaraki, Boujemaa; Cashion, John D.; Adams, Harry
• Other Names: Murray Keith S. sponsoringEditor.; Oshio Hiroki sponsoringEditor.; Real Jose Antonio sponsoringEditor.
• Is Part Of: European journal of inorganic chemistry. Issue 5/6(2013)
• Page Start: 788
• Page End: 795
• Publication Date: 2012-11-26
• Subjects: Spin crossover -- Iron -- X‐ray diffraction -- Magnetic properties -- Mössbauer spectroscopy; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201201066
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: 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 of1 and3 as solvent adducts were determined by X‐ray crystallography with LS Fe III centres found in both cases. π–π and C–H··· π interactions between the cations lead to 2D sheets that are linked to one another through C–H··· O and, in the case of3, C–H··· N/S interactions resulting in high cooperativity. Magnetic studies revealed abrupt and gradual spin crossover for3 and2, respectively. For3, spin crossover with possible thermal hysteresis was observed although solvent loss (CH2 Cl2 ) could occur. In contrast, 1 and4 were found to be low and high spin only, respectively. The results of Mössbauer spectroscopic studies are consistent with the magnetic susceptibility data and indicate that there are two low‐spin Fe III centres in2 . 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. Abstract : A series of new spin‐crossover Fe III complexes, [Fe III (qsal‐5‐OMe)2 ]Y [Y = BF4 (1 ), PF6 (2 ), NCS (3 ), BPh4 (4 )], are reported. Structural, magnetic and Mössbauer spectroscopic studies have revealed that the size and shape of the anion are crucial for controlling the nature or absence of spin crossover.