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Thermal stability of iron-sulfur clusters.
Phys Chem Chem Phys ; 20(11): 7781-7790, 2018 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-29504007
The thermal decomposition of free cationic iron-sulfur clusters FexSy+ (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 FexSy+ (y = x) or near stoichiometric FexSy+ (y = x ± 1) clusters is observed. In particular, Fe4S4+ represents the most abundant product up to 600 K, Fe3S3+ and Fe3S2+ are preferably formed between 600 K and 800 K, and Fe2S2+ 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 Fe2S2+. 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 FexOy+ clusters at high temperatures.





Texto completo: Disponível Coleções: Bases de dados internacionais Base de dados: MEDLINE Idioma: Inglês Revista: Phys Chem Chem Phys Assunto da revista: Biofísica / Química Ano de publicação: 2018 Tipo de documento: Artigo País de afiliação: Alemanha