Stabilization of high-valent FeIVS6-cores by dithiocarbamate(1−) and 1,2-dithiolate(2−) ligands in octahedral [FeIV(Et2dtc)3−n(mnt)n](n−1)− complexes (n=0, 1, 2, 3): a spectroscopic and density functional theory computational study

Milsmann, C., Sproules, S. , Bill, E., Weyhermüller, T., DeBeer George, S. and Wieghardt, K. (2010) Stabilization of high-valent FeIVS6-cores by dithiocarbamate(1−) and 1,2-dithiolate(2−) ligands in octahedral [FeIV(Et2dtc)3−n(mnt)n](n−1)− complexes (n=0, 1, 2, 3): a spectroscopic and density functional theory computational study. Chemistry: A European Journal, 16(12), pp. 3628-3645.

Abstract

A detailed spectroscopic and quantum chemical analysis is presented to elucidate the electronic structures of the octahedral complexes [Fe(Et2dtc)3−n(mnt)n]n− (1–4, n=3, 2, 1, 0) and their one-electron oxidized analogues [Fe(Et2dtc)3−n(mnt)n](n−1)− (1ox–4ox); (mnt)2− represents maleonitriledithiolate(2−) and (Et2dtc)1− is the diethyldithiocarbamato(1−) ligand. By using X-ray crystallography, Mössbauer spectroscopy, and Fe and S K-edge X-ray absorption spectroscopy (XAS) it is convincingly shown that, in contrast to our previous studies on [Fe(cyclam)(mnt)]1+ (cyclam=1,4,8,11-tetraazacyclotetradecane), the oxidation of 1–4 is metal-centered yielding the genuine FeIV complexes 1ox–4ox. For the latter complexes, a spin ground state of S=1 has been established by magnetic susceptibility measurements, which indicates a low-spin d4 configuration. DFT calculations at the B3LYP level support this electronic structure and exclude the presence of a ligand π radical coordinated to an intermediate-spin ferric ion. Mössbauer parameters and XAS spectra have been calculated to calibrate our computational results against the experiment. Finally, a simple ligand-field approach is presented to correlate the structural features obtained from X-ray crystallography (100 K) with the spectroscopic data.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sproules, Dr Stephen
• Authors: Milsmann, C., Sproules, S., Bill, E., Weyhermüller, T., DeBeer George, S., and Wieghardt, K.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Chemistry: A European Journal
• Journal Abbr.: Chem. Eur J.
• Publisher: Wiley-VCH Verlag
• ISSN: 0947-6539
• ISSN (Online): 1521-3765