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

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5633325

Huckett, S C

Ru, Rh, and Ir complexes of {kappa}-bound thiophene (T) and benzo (b)thiophenes (BTs), which serve as models for the adsorption of thiophenes on hydrodesulfurization (HDS) catalysts, have been synthesized. The Rh and Ir compound are the first dicationic transition metal complexes of either T or BTs. The BT ligands are bound to the transition metal centers via the benzene ring. The first x-ray structural characterization of a BT complex, (({eta}-C{sub 5}H{sub 5})Ru({eta}{sup 6}-BT))BF{sub 4} is reported. These model complexes react with a variety of nucleophiles (H{sup {minus}}, MeO{sup {minus}}, (MeO{sub 2}C){sub 2}CH{sup {minus}}, EtS{sup {minus}} and phosphines). The BT compounds yield the first isolable transition metal cyclohexadienyl complexes derived from fused ring aromatic ligands; four isomers of each cyclohexadienyl complex are produced. The isomers result from addition at the four tertiary carbons on the benzene ring; for the nucleophiles studied, addition occurred preferentially at the carbon closest to the sulfur atom, C7. This isomer of CpRu(BT{centered dot}H) has been characterized by an x-ray structure determination. Both (CpRu(BT)){sup +} and (CpRu(3-MeBT)){sup 2+} undergo base-catalyzed deuterium exchange of H2 and H7 in KOH/CD{sub 3}OD solutions which follows the rate law, rate = k(Ru complex)(OH{sup {minus}}). 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. These results suggest that deuterium exchange of BT over HDS catalysts does not occur when BT is {kappa}-bonded through its benzene ring.

• Research Organization: Iowa State Univ. of Science and Technology, Ames, IA (USA)
• OSTI ID: 5633325
• Country of Publication: United States
• Language: English

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CATALYSTS
CHALCOGENIDES
CHEMICAL BONDS
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
COBALT
COHERENT SCATTERING
COMPLEXES
DESULFURIZATION
DEUTERIUM
DIFFRACTION
ELEMENTS
ENERGY
HETEROCYCLIC COMPOUNDS
HYDROGEN 1
HYDROGEN ISOTOPES
HYDROGENATION
IRIDIUM COMPLEXES
ISOTOPES
ISOTOPIC EXCHANGE
LEAD COMPOUNDS
LIGHT NUCLEI
MAGNETIC RESONANCE
METALS
MOLECULAR STRUCTURE
MOLYBDENUM COMPOUNDS
MOLYBDENUM SULFIDES
NUCLEAR MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHINES
PHOSPHORUS COMPOUNDS
PLATINUM
PLATINUM METALS
POLYCYCLIC SULFUR HETEROCYCLES
REFRACTORY METAL COMPOUNDS
RESONANCE
RHENIUM
RHODIUM COMPLEXES
RUTHENIUM COMPLEXES
SCATTERING
STABLE ISOTOPES
SULFIDES
SULFUR COMPOUNDS
THIOPHENE
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X-RAY DIFFRACTION