A novel Fe(III) mol. alkoxide, [Fe(OCH3)2(dbm)]12 (1), was synthesized by the reaction of ferric chloride with dibenzoylmethane (Hdbm) and an excess of either K or Cs methylate in anhyd. MeOH. The 12 octahedrally coordinated Fe(III) ions are linked by double OCH3 bridges in a nonplanar twisted-ring structure, to give the largest cyclic ferric cluster so far reported, contg. chem. equiv. bridging units. The quant. conversion of 1 into hexairon(III) rings [MFe6(OCH3)12(dbm)6]+ (M = Li, Na) by reaction with excess alkali-metal tetraphenylborates in CH2Cl2/MeOH 3:1 was studied by 1H NMR and UV-visible spectroscopies. The reactions follow pseudo-first-order kinetics with respect to 1, with kpo(Li) = 1.07(2) × 10-2 and kpo(Na) = 1.63(3) × 10-2 s-1 at 25°. The magnetic susceptibility of 1 in the solid state is consistent with antiferromagnetic exchange interactions between the high-spin Fe(III) ions and closely follows the behavior predicted for a Heisenberg s = 5/2 quantum-spin chain down to 50 K (J = 22.2 cm-1 for H=J Σi Si·Si+1 and g = 2.00). At low temps. the magnetic behavior is dominated by the energy gap between the ground S = 0 and the 1st excited S = 1 state, which is a consequence of finite-size effects.
[Fe(OCH3)2(dbm)]12: Synthesis, Solid-state Characterization and Reactivity of a New Molecular Ferric Wheel / G. L., Abbati; A., Caneschi; Cornia, Andrea; FABRETTI COSTANTINO, Antonio; D., Gatteschi. - In: INORGANICA CHIMICA ACTA. - ISSN 0020-1693. - STAMPA. - 297(2000), pp. 291-300.
Data di pubblicazione: | 2000 |
Titolo: | [Fe(OCH3)2(dbm)]12: Synthesis, Solid-state Characterization and Reactivity of a New Molecular Ferric Wheel |
Autore/i: | G. L., Abbati; A., Caneschi; Cornia, Andrea; FABRETTI COSTANTINO, Antonio; D., Gatteschi |
Autore/i UNIMORE: | |
Rivista: | |
Volume: | 297 |
Pagina iniziale: | 291 |
Pagina finale: | 300 |
Codice identificativo ISI: | WOS:000084949800036 |
Codice identificativo Scopus: | 2-s2.0-0033806527 |
Citazione: | [Fe(OCH3)2(dbm)]12: Synthesis, Solid-state Characterization and Reactivity of a New Molecular Ferric Wheel / G. L., Abbati; A., Caneschi; Cornia, Andrea; FABRETTI COSTANTINO, Antonio; D., Gatteschi. - In: INORGANICA CHIMICA ACTA. - ISSN 0020-1693. - STAMPA. - 297(2000), pp. 291-300. |
Tipologia | Articolo su rivista |
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