Ruthenium, rhodium, and iridium complexes of thiophene and benzo(b)thiophienes: Models for catalytic hydrodesulfurization

Technical Report · Sun Nov 01 04:00:00 EST 1987

OSTI ID:5354214

Huckett, S C

Ru, Rh, and Ir complexes of ..pi..-bound thiophene (T) and benzo(b)thiophenes (BTs), which serve as models for the adsorption of thiophenes on hydrodesulfurization (HDS) catalysts, have been synthesized. X-ray structural characterization of ((eta-C/sub 5/H/sub 5/)Ru(eta/sup 6/-BT))BF/sub 4/ is reported. These model complexes react with nucleophiles (H/sup -/, MeO/sup -/, (MeO/sub 2/C)/sub 2/CH/sup -/, EtS/sup -/ and phosphines). The BT compounds yield isolable transition metal cyclohexadienyl complexes derived from fused ring aromatic lagands;four isomers of each cyclohexadienyl complex are produced. This isomer of CpRu(BT . H) has been characterized by an x-ray structure determination. The T complexes react with phosphines to produce (Cp*Ir(eta/sup 4/-T . PR/sub 3/))/sup 2 +/. Double nucleophilic addition reactions (H/sup -/ and MeO/sup -/) of (Cp*Ir(BT))/sup 2 +/ and (Cp*Ir(3-MeBT))/sup 2 +/ are also discussed. Reaction of either NaBEt/sub 3/H or Cp/sub 2/Co with (Cp*Ir(T))/sup 2 +/ results in a 2e/sup -/ reduction of the Ir complex. This product is identified as Cp*Ir(eta/sup 4/-T). Both (CpRu(BT))/sup +/ and (CpRu(3-MeBT))/sup +/ undergo base-catalyzed deuterium exchange of H2 and H7 in DOHCD/sub 3/OD solutions which follows the rate law, rate = k(Ru complex)(OH/sup -/). The mechanism is proposed to involve rate-determining proton abstraction from either (CpRu(BT))/sup +/, or (CpRu(3-MeBT))/sup +/, followed by addition of D/sup +/ from the CD/sub 3/OD solvent to give the deuterated BT complex. Heterogeneous reactor studies of deuterium exchange of BT over several HDS catalysts (PbMo/sub 6.2/S/sub 8/, 1% Pt-10% Re..gamma..-Al/sub 2/O/sub 3/, Co/sub 0.25/MoS, and 5% Re..gamma..-Al/sub 2/O/sub 3/) and ..gamma..-Al/sub 2/O/sub 3/ indicate that BT is activated to exchange at the 2- and 3-positions over the catalysts

• Research Organization: Ames Lab., IA (USA)
• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5354214
• Report Number(s): IS-T-1322; ON: DE88007614
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKENES
CATALYSTS
CHEMICAL REACTIONS
COMPLEXES
CYCLOALKENES
CYCLOPENTADIENE
DESULFURIZATION
DEUTERIUM
DIENES
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
HYDROGEN ISOTOPES
IRIDIUM COMPLEXES
ISOTOPES
ISOTOPIC EXCHANGE
LIGHT NUCLEI
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
POLYENES
RHODIUM COMPLEXES
RUTHENIUM COMPLEXES
STABLE ISOTOPES
THIONAPHTHENES
THIOPHENE
TRANSITION ELEMENT COMPLEXES