Selenophene transition metal complexes

Thesis/Dissertation · Wed Jul 27 04:00:00 EDT 1994

DOI:https://doi.org/10.2172/10190649· OSTI ID:10190649

White, Carter James ^[1]

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1. Iowa State Univ., Ames, IA (United States)

This research shows that selenophene transition metal complexes have a chemistry that is similar to their thiophene analogs. Selenophene coordination has been demonstrated and confirmed by molecular structure in both the η⁵- and the η¹(Se)-coordination modes. The reaction chemistry of selenophene complexes closely resembles that of the analogous thiophene complexes. One major difference, however, is that selenophene is a better donor ligand than thiophene making the selenophene complexes more stable than the corresponding thiophene complexes. The ⁷⁷Se NMR chemical shift values for selenophene complexes fall within distinct regions primarily depending on the coordination mode of the selenophene ligand. In the final paper, the C-H bond activation of η¹(S)-bound thiophenes, η¹(S)-benzothiophene and η¹(Se)-bound selenophenes has been demonstrated. The deprotonation and rearrangement of the η¹(E)-bound ligand to the carbon bound L-yl complex readily occurs in the presence of base. Reprotonation with a strong acid gives a carbene complex that is unreactive towards nucleophilic attack at the carbene carbon and is stable towards exposure to air. The molecular structure of [Cp(NO)(PPh₃)Re(2-benzothioenylcarbene)]O₃SCF₃ was determined and contains a Re-C bond with substantial double bond character. Methyl substitution for the thienylcarbene or selenylcarbene gives a carbene that rearranges thermally to give back the η¹(E)-bound complex. Based on these model reactions, a new mechanism for the H/D exchange of thiophene over the hydrodesulfurization catalyst has been proposed.

• Research Organization: Iowa State Univ. of Science and Technology, Ames, IA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 10190649
• Report Number(s): IS-T--1699; ON: DE95001675
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010402
02 PETROLEUM
020400
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201
CHEMICAL ACTIVATION
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DESULFURIZATION
EXPERIMENTAL DATA
NUCLEAR MAGNETIC RESONANCE
POLYCYCLIC SULFUR HETEROCYCLES
PROCESSING
PURIFICATION AND UPGRADING
SELENIUM 77
SELENIUM COMPLEXES