In:
Chemistry – A European Journal, Wiley
Abstract:
Partial ligand substitution at the iron pentacarbonyl radical cation generates novel half‐sandwich complexes of the type [Fe(η 6 ‐arene)(CO) 2 ]⋅ + (arene=1,3,5‐tri‐ tert ‐butylbenzene, 1,3,5‐trimethylbenzene, benzene and fluorobenzene). Of those, the bulkier 1,3,5‐tri‐ tert ‐butylbenzene (mes*) derivative [Fe(mes*)(CO) 2 ]⋅ + was fully characterized by XRD analysis, IR, NMR, cw‐EPR, Mössbauer spectroscopy and cyclic voltammetry as the [Al(OR F ) 4 ] − (R F =C(CF 3 ) 3 ) salt. Chemical electronation, i. e., the single electron reduction, with decamethylferrocene generates neutral [Fe(mes*)(CO) 2 ], whereas further deelectronation under CO‐pressure leads to a dicationic three‐legged [Fe(mes*)(CO) 3 ] 2+ salt with [Al(OR F ) 4 ] − counterion. The full substitution of the carbonyl ligands in [Fe(CO) 5 ]⋅ + [Al(OR F ) 4 ] − mainly resulted in disproportionation reactions, giving solid Fe(0) and the dicationic bis‐arene salts [Fe(η 6 ‐arene) 2 ] 2+ ([Al(OR F ) 4 ] − ) 2 (arene=1,3,5‐trimethylbenzene, benzene and fluorobenzene). Only by employing the very large fluoride bridged anion [F‐{Al(OR F ) 3 } 2 ] − , it was possible to isolate an open shell bis‐arene cation salt [Fe(C 6 H 6 ) 2 ]⋅ + [F‐{Al(OR F ) 3 } 2 ] − . The highly reactive cation was characterized by XRD analysis, cw‐EPR, Mössbauer spectroscopy and cyclic voltammetry. The disproportionation of [Fe(C 6 H 6 ) 2 ]⋅ + salts to give solid Fe(0) and [Fe(C 6 H 6 ) 2 ] 2+ salts was analyzed by a suitable cycle, revealing that the thermodynamic driving force for the disproportionation is a function of the size of the anion used and the polarity of the solvent.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.202400105
Language:
English
Publisher:
Wiley
Publication Date:
2024
detail.hit.zdb_id:
1478547-X
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