Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models

Glaser T, Beissel T, Bill E, Weyhermuller T, Schunemann V, Meyer-Klaucke W, Trautwein AX, Wieghardt K (1999)
Journal of the American Chemical Society 121(10): 2193-2208.

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Zeitschriftenaufsatz | Veröffentlicht | Englisch
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Abstract / Bemerkung
The reaction of mononuclear [LFeIII] where L represents the trianionic ligand 1,4,7-tris(4-tert-butyl-2-mercaptobenzyl)-1,4,7-triazacyclononane with CrSO4. 5H2O, CoCl2. 6H2O, or Fe(BF4)2. 6H2O and subsequent oxidation with ferrocenium hexafluorophosphate or NO(BF4) or reduction with [(tmcn)Mo(CO)3] (tmcn = 1,4,7-trimethyl-1,4,7-triazacyclononane) produced an isostructural series of [LFeMFeL]n+ complexes, the following salts of which were isolated as crystalline solids: (i) [LFeCrFeL](PF6)n with n = 1 (1a), n = 2 (1b), and n = 3 (1c); (ii) [LFeCoFeL]Xn with X = BPh4 and n = 2 (2b) and X = PF6 and n = 3 (2c); (iii) [LFeFeFeL](BPh4)n with n = 2 (3b) and n = 3 (3c). All compounds contain Linear trinuclear cations (face-sharing octahedral) with an N3Fe(mu-SR)3M(mu-SR)3FeN3 core structure. The electron structure of all complexes has been studied by Fe and M K-edge X-ray absorption near edge structure (XANES), UV-vis, and EPR spectroscopy, variable-temperature, variable-field susceptibility measurements, and Mossbauer spectroscopy (in zero and applied field). The following electronic structures have been established: (1a) FeII(ls)CrIIIFeII(ls) (ls = low-spin) with a spin ground state of St = 3/2; (1c) FeIII(ls)CrIIIFeIII(ls) with an St = 1/2 ground state; (2c) FeIII(ls)CoIII(ls)FeIII(ls) with an St = 1 ground state; (3c) FeIII(ls)FeIII(ls)FeIII(ls) with an St = 1/2 ground state. For 1b (St = 2) it is found that the two iron ions are spectroscopically equivalent (Fe2.5) and, therefore, the excess electron is delocalized (class III): [LFe2.5CrIIIFe2.5L]2+. For 2b clearly two different iron sites prevail at low temperatures (4.2 K); at higher temperatures (>200 K) they become equivalent on the Mossbauer time scale. Thus, 2b is class II with temperature-dependent electron hopping between the FeII and FeIII ions. 3b is again fully delocalized (class III) with an St = 1 ground state; the excess electron is delocalized over all three iron sites. The electronic structure of all complexes is discussed in terms of double exchange and superexchange mechanisms.
Erscheinungsjahr
Zeitschriftentitel
Journal of the American Chemical Society
Band
121
Zeitschriftennummer
10
Seite
2193-2208
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Glaser T, Beissel T, Bill E, et al. Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models. Journal of the American Chemical Society. 1999;121(10):2193-2208.
Glaser, T., Beissel, T., Bill, E., Weyhermuller, T., Schunemann, V., Meyer-Klaucke, W., Trautwein, A. X., et al. (1999). Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models. Journal of the American Chemical Society, 121(10), 2193-2208. doi:10.1021/ja982898m
Glaser, T., Beissel, T., Bill, E., Weyhermuller, T., Schunemann, V., Meyer-Klaucke, W., Trautwein, A. X., and Wieghardt, K. (1999). Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models. Journal of the American Chemical Society 121, 2193-2208.
Glaser, T., et al., 1999. Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models. Journal of the American Chemical Society, 121(10), p 2193-2208.
T. Glaser, et al., “Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models”, Journal of the American Chemical Society, vol. 121, 1999, pp. 2193-2208.
Glaser, T., Beissel, T., Bill, E., Weyhermuller, T., Schunemann, V., Meyer-Klaucke, W., Trautwein, A.X., Wieghardt, K.: Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models. Journal of the American Chemical Society. 121, 2193-2208 (1999).
Glaser, Thorsten, Beissel, T, Bill, E, Weyhermuller, T, Schunemann, V, Meyer-Klaucke, W, Trautwein, AX, and Wieghardt, K. “Electronic structure of linear thiophenolate-bridged heterotrinuclear complexes [LFeMFeL]n(+) (M = Cr, Co, Fe; n = 1-3): Localized vs delocalized models”. Journal of the American Chemical Society 121.10 (1999): 2193-2208.