Dimerized Spin‐Crossover Iron(II) Complexes as Supramolecular Anion Capsules. Issue 5 (16th January 2013)

• Record Type: Journal Article
• Authors: Shiga, Takuya; Oshiro, Emiko; Nakayama, Naoko; Mitsumoto, Kiyotaka; Newton, Graham N.; Nishikawa, Hiroyuki; Oshio, Hiroki
• 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: 781
• Page End: 787
• Publication Date: 2013-01-16
• Subjects: Spin crossover -- Magnetic properties -- Supramolecular chemistry -- Host–guest systems -- Iron; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201201365
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract: Two dimerized iron(II) complexes, [{Fe(L )(HL )2 }{Fe(HL )3 }](PF6 )(BF4 )2 · 5CH3 CN· 4H2 O (1 ) and [{Fe(L )(HL )2 }{Fe(HL )3 }](PF6 )(FeCl4 )2 (2 ) {HL = 3‐(2‐pyridyl)‐5‐[4‐(diphenylamino)phenyl]‐1 H ‐pyrazole}, supported by triphenylamine‐derivatized bidentate ligands and encapsulating hexafluorophosphate ions were synthesized. The complex iron ions have octahedral coordination geometries in which they interact with six nitrogen atoms from three bidentate ligands. Both compounds have capsule‐like dimerized supramolecular structures, in which the arrangements of the bulky ligands of two discrete mononuclear complexes create a central cavity in which a single hexafluorophosphate ion is captured. The bidentate ligands interact with the anionic guest molecules through the hydrogen atoms of the ligand pyrazole moieties. Cryomagnetic studies reveal that both compounds show spin‐crossover behavior. Complex1 showed quasi‐reversible spin‐crossover around 200–300 K, hindered by desolvation effects, whereas2 showed reversible gradual spin‐crossover behavior. The electronic states of the iron ions resulting from the spin‐crossover were confirmed by X‐ray structure analyses and Mössbauer spectra. Abstract : Two iron(II) complexes were synthesized using bulky capping ligands. They formed a dimerized capsulelike superstructure within which a hexafluorophosphate anion was encapsulated. The complexes were investigated by cryomagnetic studies, X‐ray structural analyses, and Mössbauer spectra.