Thermal stability of iron–sulfur clusters. Issue 11 (5th March 2018)

• Record Type: Journal Article
• Authors: Lang, Sandra M.; Miyajima, Ken; Bernhardt, Thorsten M.; Mafuné, Fumitaka; Barnett, Robert N.; Landman, Uzi
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 11(2018)
• Page Start: 7781
• Page End: 7790
• Publication Date: 2018-03-05
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c8cp00515j
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Fe x S y + clusters thermally decompose via a complex fragmentation mechanism with the preferred formation of stoichiometric Fe x S x + . Abstract : The thermal decomposition of free cationic iron–sulfur clusters Fe x S y + ( x = 0–7, y = 0–9) is investigated by collisional post-heating in the temperature range between 300 and 1000 K. With increasing temperature the preferential formation of stoichiometric Fe x S y + ( y = x ) or near stoichiometric Fe x S y + ( y = x ± 1) clusters is observed. In particular, Fe4 S4 + represents the most abundant product up to 600 K, Fe3 S3 + and Fe3 S2 + are preferably formed between 600 K and 800 K, and Fe2 S2 + clearly dominates the cluster distribution above 800 K. These temperature dependent fragment distributions suggest a sequential fragmentation mechanism, which involves the loss of sulfur and iron atoms as well as FeS units, and indicate the particular stability of Fe2 S2 + . The potential fragmentation pathways are discussed based on first principles calculations and a mechanism involving the isomerization of the cluster prior to fragmentation is proposed. The fragmentation behavior of the iron–sulfur clusters is in marked contrast to the previously reported thermal dissociation of analogous iron-oxide clusters, which resulted in the release of O2 molecules only, without loss of metal atoms and without any tendency to form particular prominent and stable Fe x O y + clusters at high temperatures.