Synthesis, characterization and reactivity of several rhenium hydride complexes. A study of the role of metal hydrides in organometallic reactions
The mechanistic role of transition metal hydrides in organometallic reactions has been studied using several low valent, electron rich rhenium complexes. The reaction ReH[sub 7](PPh[sub 3])[sub 2] with indene has been found to yield products that are [eta][sup 5]-C[sub 9]H[sub 7]ReH[sub 2](PPh[sub 3])[sub 2] and ([eta][sup 5]-C[sub 9]H[sub 11])ReH[sub 2](PPh[sub 3])[sub 2], respectively. The mechanism proposed for the formation of these two products consists of several metal to ring hydride migrations, and the activation parameters for one of the migrations have been obtained. Hydride migrations are prevalent in the subsequent chemistry of ([eta][sup 5]-C[sub 9]H[sub 11])ReH[sub 2](PPh[sub 3])[sub 2], as well as in the similar complex ([eta][sup 4]-C[sub 9]H[sub 12])ReH[sub 3](PPh[sub 3])[sub 2]. The complex ([eta][sup 4]-C[sub 4]H[sub 5]S)ReH[sub 2](PPh[sub 3])[sub 2] has been synthesized and structurally characterized in an attempt to model the interaction of thiophene with a metal hydride surface which is presumably present during typical hydrodesulfurization conditions. The thermolysis of ([eta][sup 4]-C[sub 4]H[sub 5]S)ReH[sub 2](PPh[sub 3])[sub 2] in the presence of PMe[sub 3] has been found to yield free tetrahydrothiophene and the cyclometallated Re(PMe[sub 3])[sub 4](PPH[sub 2]C[sub 6]H[sub 4]), while photolysis with excess PMe[sub 3] yields a mixture of organometallic products in which the thiophene ligand has undergone C-S bond cleavage. Products have been identified that contain an S-bound 1-butene-1-thiolate ligand, an [eta][sup 3]-allyl bound 1-butene-1-thiolate ligand, an ethylthioketene ligand and an S-bound 1-butanethiolate ligand, all of which represent the first such homogeneous transformations of thiophene. The photochemical ligand exchange reactions and the observed H/D exchange catalysis (between a deuterated solvent and a protio substrate) of CpReH[sub 2](PPh[sub 3])[sub 2] have been studied in detail.
- Research Organization:
- Rochester Univ., NY (United States)
- OSTI ID:
- 7102249
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
CATALYTIC EFFECTS
CHEMICAL PREPARATION
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
DESULFURIZATION
HETEROCYCLIC COMPOUNDS
HYDRIDES
HYDROGEN COMPOUNDS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOMETALLIC COMPOUNDS
REFRACTORY METAL COMPOUNDS
RHENIUM COMPOUNDS
RHENIUM HYDRIDES
SYNTHESIS
THIOPHENE
TRANSITION ELEMENT COMPOUNDS