Thermolysis of Cp*Rh{(η41-C4Me4S)Fe(CO)4}: A Case Study in Thiophene Desulfurization

Shifang Luo, Ann E. Ogilvy, Thomas B. Rauchfuss, Arnold L. Rheingold, Scott R. Wilson

Research output: Contribution to journalArticlepeer-review

Abstract

Cp*Rh(η4-C4Me4S) (1) and Fe3(CO)12 react to give the ferrole Cp*Rh{η5-C4Me4Fe(CO)3} (3) together with trace amounts of Cp*Rh{(η41-C4Me 4S)Fe(CO)4} (2). Compound 2 was prepared in high yield by the reaction of 1 with Fe(CO)5 in the presence of Me3NO. Thermolysis of 2 in refluxing toluene gave 3, free C4Me4S (tetramethylthiophene, TMT), and (Cp*Rh)2(μ-CO)(μ3-S)Fe(CO)3 (4) in ca. 2:2:1 molar ratio. The efficiency of the conversion of 2 to 3 increased with added Fe3(CO)12 concomitant with the diminution of the yield for 4. Control experiments showed that 3 and 4 are stable to Fe3(CO)12 in refluxing toluene. Furthermore, by labeling both the rhodium, with C5Me4Et, and the thiophene, as C4Me4S-3,4-d2, we showed that the Rh-C4Me4S moiety remains intact during its desulfurization. The structures of 2-4 were determined by single-crystal X-ray diffraction. The desulfurization process illustrates the following mechanistic points: (i) transition metals play a dual role in thiophene desulfurization by separately stabilizing the desulfurized hydrocarbon and accepting the sulfur, (ii) the hydrocarbon is stabilized in the form of a metallacycle that structurally resembles thiophene, and (iii) the hydrocarbon and sulfide are stabilized in heterometallic environments.

Original languageEnglish (US)
Pages (from-to)1002-1009
Number of pages8
JournalOrganometallics
Volume10
Issue number4
DOIs
StatePublished - Apr 1 1991

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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