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Synthesis, Structure, Electrochemistry, and Magnetism of [Mn III Mn III ], [Mn III Fe III ] and [Fe III Fe III ] Cores: Generation of Phenoxyl Radical Containing [Fe III Fe III ] Species
Author(s) -
Verani Cláudio Nazari,
Bothe Eberhard,
Burdinski Dirk,
Weyhermüller Thomas,
Flörke Ulrich,
Chaudhuri Phalguni
Publication year - 2001
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200108)2001:8<2161::aid-ejic2161>3.0.co;2-k
Subject(s) - chemistry , magnetism , electrochemistry , nanotechnology , electrode , condensed matter physics , physics , materials science
Neutral homo‐ and heterobinuclear complexes with the general formula [(tmtacn)M A (salox) 3 M B ] where M A (Mn III or Fe III ) is facially coordinated to the cyclic amine 1,4,7‐trimethyl‐1,4,7‐triazacyclononane (tmtacn) and M B (Mn III or Fe III ) is coordinated to the azomethine nitrogens and phenolate oxygens of the bridging ligand, salicylaldoxime, thus yielding M A N 3 O 3 and M B N 3 O 3 cores. The compounds were characterized by IR, UV/Vis, mass spectrometry, Mössbauer spectroscopy, electrochemistry, and variable‐temperature (2−295 K) magnetic susceptibility measurements. The molecular structures of the compounds [(tmtacn)Fe III (salox) 3 Fe III ] ( 3 ) and [(tmtacn)Fe III ( t BuSalox) 3 Fe III ] ( 4 ) were established by X‐ray diffraction. Three oximate groups −HC=N−O bridge the metal centers with Fe ··· Fe separations of 3.571(1) and 3.486(1) Å for ( 3 ) and ( 4 ), respectively. Analysis of the susceptibility data yields antiferromagnetic interactions between the metal centers for the complexes Fe III Fe III and Mn III Fe III , but a ferromagnetic interaction for Mn III Mn III . The electrochemistry of all complexes was investigated in detail. For the complexes Fe III Fe III ( 3 ) and ( 4 ) a series of reversible one‐electron transfer waves leads to the formation of the cations [Fe 2 ] 1+/2+/3+ that are attributed to the generation of salox‐based phenoxyl radicals.