Redox and "antioxidant" Properties of Fe 2 (μ-SH) 2 (CO) 4 (PPh 3 ) 2

Husain N. Kagalwala, Noémie Lalaoui, Qian Li Li, Liang Liu, Toby Woods, Thomas B. Rauchfuss

Research output: Contribution to journalArticle

Abstract

The chemistry of Fe 2 (μ-SH) 2 (CO) 4 (PPh 3 ) 2 (2 HH ) is described with attention to S-S coupling reactions. Produced by the reduction of Fe 2 (μ-S 2 )(CO) 4 (PPh 3 ) 2 (2), 2 HH is an analogue of Fe 2 (μ-SH) 2 (CO) 6 (1 HH ), which exhibits well-behaved S-centered redox. Both 2 HH and the related 2 MeH exist as isomers that differ with respect to the stereochemistry of the μ-SR ligands (R = H, Me). Compounds 2 HH , 2 MeH , and 2 protonate to give rare examples of Fe-SH and Fe-S 2 hydrides. Salts of [H2] + , [H2 HH ] + , and [H2 MeH ] + were characterized crystallographically. Complex 2 HH reduces O 2 , H 2 O 2 , (PhCO 2 ) 2 , and Ph 2 N 2 , giving 2. Related reactions involving 1 HH gave uncharacterizable polymers. The differing behaviors of 2 HH and 1 HH reflect stabilization of the ferrous intermediates by the PPh 3 ligands. When independently generated by the reaction of 2 HH with 2,2,6,6-tetramethyl-1-piperidinyloxy, 2∗ quantitatively converts to 2 or, in the presence of C 2 H 4 , is trapped as the ethanedithiolate Fe 2 (μ-S 2 C 2 H 4 )(CO) 4 (PPh 3 ) 2 . Evidence is presented that the Hieber-Gruber synthesis of 1 involves polysulfido intermediates [Fe 2 (μ-S n ) 2 (CO) 6 ] 2- (n > 1). Two relevant experiments are as follows: (i) protonation of [Fe 4 (μ-S) 2 (μ-S 2 )CO) 12 ] 2- gives 1 and 1 HH , and (ii) oxidation of 1 HH by sulfur gives 1.

Original languageEnglish (US)
Pages (from-to)2761-2769
Number of pages9
JournalInorganic Chemistry
Volume58
Issue number4
DOIs
StatePublished - Feb 18 2019

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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