Combined Moessbauer and EPR studies of the S = 3 state of an exchange-coupled Fe sup III Cu sup II complex: Test for quantitative EPR analysis of integer spin systems
- Univ. of Minnesota, Navarre (USA)
- Univ. of Minnesota, Minneapolis (USA)
The authors have studied acetonitrile solutions of the bimetallic complex (Fe{sup III}Cu{sup II}(BPMP)Cl{sub 2})(BPh{sub 4}){sub 2}, where BPMP is the anion 2,6-bis((bis(2-pyridylmethyl)amino)methyl)-4-methylphenol, with Moessbauer and EPR spectroscopy. Both spectroscopic techniques show that the complex is ferromagnetically coupled (H = JS{sub 1} {center dot} S{sub 2}, J < 0) to yield a ground state spin S = 3. Analysis of the Moessbauer spectra taken in applied fields up to 6.0 T yielded for the Fe{sup III} site the zero-field splitting parameters D{sub 1} = +1.2 cm{sup {minus}1} and E{sub 1} = 0.11 cm{sup {minus}1}, the magnetic hyperfine coupling constant A{sub 0} = -28.8 MHz, quadrupole spitting {Delta}E{sub Q} = 0.67 mm/s, and isomer shift {delta} = 0.48 mm/s. The zero-field splitting term of the ferric ion mixes the excited S = 2 multiplet with the ground manifold, the mixing being proportional to D{sub 1}/J; by analyzing this mixing they have determined that {minus}2 cm{sup {minus}1} > J > {minus}5 cm{sup {minus}1}. The Fe{sup III}Cu{sup II} complex gives an x-band resonance at g = 12 which they have studied with a bimodal cavity in the temperature range from 2 to 50 K. They have analyzed the position and line shape of the g = 12 signal with a computer program in the framework of an S = 3 spin Hamiltonian, allowing a Gaussian distribution of the zero-field splitting parameters D and E. Finally, they have determined S = 3 spin concentration from spectral simulations relative to a known standard; the value obtained agrees with the optically determined concentration.
- OSTI ID:
- 5170928
- Journal Information:
- Journal of the American Chemical Society; (United States), Vol. 113:2; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COPPER COMPLEXES
ELECTRON SPIN RESONANCE
IRON COMPLEXES
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
MEASURING METHODS
MOESSBAUER EFFECT
COMPLEXES
DATA
INFORMATION
MAGNETIC RESONANCE
NUMERICAL DATA
RESONANCE
TRANSITION ELEMENT COMPLEXES
360602* - Other Materials- Structure & Phase Studies