Variable-temperature 57Fe Mössbauer emission studies on tris (2-x-1,10-phenanthroline) 57Co(II)perchlorate (x=Cl, CH3O)
✍ Scribed by J. Fleisch; P. Gütlich
- Publisher
- Elsevier Science
- Year
- 1977
- Tongue
- English
- Weight
- 614 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Two paramagnetic 4Tt (Oh) diimine complexes of cobalt (II), [s7Co(2CH~O-phen)~ j(CIO& -Ha0 and js7Co(2CE phen)s ](ClO& -Hz0 (2-CHsO-phcn = 2-methoxyphenanthrohne, 2C1-phen = 2-chlorophenanthroline), have been prepared in polycrystalline form and investigated by 57Fe Mossbauer emission spectroscopy at variable temperatures versus 57Fe enriched K4 [Fe(CN)bJ -3H20 (298 K) as absorber. The emission spectra of the "weak-field" system with &CL-phen ligands agree with previously published absorption spectra of the iron analoguc in the whole temperature range of 293-S K. In case of the "intermediate-field" systerr, with Z-CHXO-phen ligands, however, anomalous spin quintet states of iron(H) have been observed in emission at low temperatures,
where the corresponding iron(H) complex, recently described as a typical spin cross-over system, exhibits mostly low-spin behaviour.