Low-temperature Mössbauer Spectroscopy Study of Some Partially Solvated Tris(dialkyldithiocarbamato)iron(III) Complexes
The possibility of stabilization of a spin-quartet ground state
The low-temperature, zero-field Mössbauer spectra of tris(morpholinecarbodithioato)iron(III), partially solvated with CHCl 3, CH 2Cl 2, or C 6H 6, and the pyrrolidyl analogue solvated with benzene are presented. Contrary to previous susceptibility studies in which limiting low-temperature magnetic moments of ∼4 μ B were used to suggest a sextet to ground quartet transition with decreasing temperature, the present Mössbauer spectra clearly indicate the presence of only spin-sextet and -doublet states; S = 3/2 is never the ground state. Slow paramagnetic relaxation spectra of the sextet fractions correspond to the expected limiting internal fields of ∼450 kG while the spin-doublet fractions exhibit no hyperfine splitting, again as expected. Previous susceptibility results are reinterpreted in terms of a combination of zero-field splitting of a “permanent” fraction of S = 5/2 state, population of the S = 1/2 state, and weak antiferromagnetic interactions of the discrete FeS 6 cores involving metal-electron spin density delocalized to the thio ligands. © 1981 American Chemical Society.
G. A. Eisman et al., "Low-temperature Mössbauer Spectroscopy Study of Some Partially Solvated Tris(dialkyldithiocarbamato)iron(III) Complexes," Inorganic Chemistry, American Chemical Society (ACS), Jan 1981.
The definitive version is available at http://dx.doi.org/10.1021/ic50224a065
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© 1981 American Chemical Society (ACS), All rights reserved.