Premium
Spin States, Bonding and Magnetism in Mixed‐Valence Iron(0)‐Iron(II) Complexes **
Author(s) -
Kim Daniel,
Wilson Daniel W. N.,
Fataftah Majed S.,
Mercado Brandon Q.,
Holland Patrick L.
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202104431
Subject(s) - chemistry , magnetism , valence (chemistry) , crystallography , metal , mössbauer spectroscopy , ligand (biochemistry) , electronic structure , spin states , inorganic chemistry , computational chemistry , condensed matter physics , physics , biochemistry , receptor , organic chemistry
“Xenophilic” complexes offer metal‐metal bonds between disparate metal sites, but the nature of the metal‐metal bonding is often unclear. Here, we describe two novel complexes with unsupported Fe−Fe bonds, L x Fe−Fp (L X = β‐aldiminate or β‐diketiminate; Fp = Fe(CO) 2 Cp), that offer insight into Fe−Fe bonding. Mössbauer, magnetism, and DFT analysis indicate that the most accurate electronic structure description is LFe II ←Fe 0 (CO) 2 Cp, in which the Fe(CO) 2 Cp is low‐spin iron(0) and acts as an X‐type ligand toward the high‐spin iron(II) of the LFe fragment. This largely electrostatic interaction has a bond order of only 0.5. The three‐coordinate high‐spin iron(II) site has large zero‐field splitting, and in addition its Mössbauer parameters can be used to rank the Fp − “metalloligand” as a donor; it is nearly as strong a donor as phosphides and alkyls.