| Autor: |
W.M. Reif, J.E. Baldwin, H. Wong, J. Huff |
| Rok vydání: |
1977 |
| Předmět: |
|
| Zdroj: |
Inorganica Chimica Acta. 25:91-96 |
| ISSN: |
0020-1693 |
| DOI: |
10.1016/s0020-1693(00)95695-0 |
| Popis: |
The magnetic susceptibility of a four coordinate, approximately square planar iron(II) complex of a substituted octa-aza [14] annulene of known structure has been studied over the range 1.6 to 300 K. The compound contains an FeN 4 chromophore and exhibits essentially spin-only magnetic behavior (μ eff = 2.94 μ β at 300 K) to as low as 25 K. Below this temperature zero-field splitting is evident, D ∼ 14 cm −1 , with the effective moment decreasing to 1.34 μ β at 1.6 K. Zero-field Mossbauer spectra have been measured over the range 300–4.2 K and this system as well as another less hindered analogue are found to have the largest quadrupole interactions (∼4 mm/sec) yet reported for triplet iron(II) complexes. The Mossbauer spectra also suggest temperature dependence of the recoil free fraction (Goldanskii-Karyagin effect). The large quadrupole effect is consistent with either a 3 B or 3 E ground term (based on 3 T 2g of O h ) with negligible reduction of the electric field gradient by cocalency effets. A reevaluation of the current use of Mossbauer spectroscopy data in distinguishing spin-triplet versus singlet iron(II) is made. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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