Anomalous Spin Crossover of Mechanically Strained Iron(II) Complexes with 1,10-Phenanthroline with Their Counterions, NCS− and PF−6
✍ Scribed by Naoko Tsuchiya; Atsushi Tsukamoto; Tadashi Ohshita; Tetsuhiko Isobe; Mamoru Senna; Naoki Yoshioka; Hidenari Inoue
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 237 KB
- Volume
- 153
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
E4ects of counterions on the change in the magnetic behavior due to mechanical amorphization have been examined on iron(II) complexes with 1,10-phenanthroline, Fe(phen) 2 (NCS) 2 , Fe(phen) 3 2 ' H 2 O, and [Fe(phen) 3 ](PF 6 ) 2 , at temperatures between 2 K and 300 K. Amorphization results in the increase in M T, where M is molar magnetic susceptibility and T is temperature, in two modes, i.e., a jump at temperatures below 20 K and a subsequent gradual increase. The 5rst mode is attributed to the mechanically induced high spin state ( 5 T g ) which is made metastable below 20 K. The second is the thermally induced transition from a low spin ( 1 A g ) to a high spin ( 5 T 2g ) state for the distorted complexes with the widened distribution of the ligand 5eld strength. The stabilization of the HS state is mainly due to the ligand 5eld distortion caused by mechanical amorphization. Coordination of ionic species, NCS ؊ and PF ؊ 6 , originally serving as counterions, plays a signi5cant role in the ligand 5eld distortion.