Polyhydride and dihydrogen complexes: Structure and reactivity

Miscellaneous · Fri Jan 01 00:00:00 EST 1993

OSTI ID:6930912

Michos, D

This thesis studies interaction of dihydrogen with transition metal complexes. Synthesis and characterization of [ReH[sub 2](CO)[sub 2](PMe[sub 2]Ph)[sub 3]][sup +], a dihydride complex with classical and nonclassical tautomeric forms in equilibrium, are described. The equilibrium constant and other thermodynamic parameters are examined. The structural differences between the above complex and the closely related [ReH[sub 2](CO)(PMe[sub 2]Ph)[sub 4]][sup +] complex are discussed. The preparation and spectroscopic characterization of ruthenium dihydrogen complexes of the type [RuH([eta][sup 2]-H[sub 2])(L)(triphos)][sup +] are presented. In the partially deuterated complexes, the rare trans isotope effect on the chemical shift of [eta][sup 2]-HD is observed. The first tungsten hexahydrides WH[sub 6](triphos) and an unusual silyl polyhydride WH[sub 5](SiR[sub 3])(triphos) supported by tridentate phosphines (triphos) are synthesized and the fluxional behavior is presented. Structural control in ReH[sub 7](P(C[sub 6]H[sub 4]-p-X)[sub 3])[sub 2] complexes is achieved by modulating the electronic properties of the ligands. These complexes, which contain an elongated [eta][sup 2]-H[sub 2] ligand, undergo a systematic change in the H[center dot][center dot][center dot]H distance of the [eta][sup 2]-dihydrogen, in response to the electronic influence of substituents on the phosphine ligand, and a continuum of H[center dot][center dot][center dot]H distances is proposed. The synthesis and characterization of rhenium complexes with the new mixed phosphorus-nitrogen-donor ligand NPh(CH[sub 2]CH[sub 2]PPh[sub 2])[sub 2] are described. Complex [ReH[sub 4]([eta][sup 2]-H[sub 2])(NPh(CH[sub 2]CH[sub 2]PPh[sub 2])[sub 2])][sup +] is the first d[sup 2] rhenium dihydrogen complex with a short H[center dot][center dot][center dot]H distance. Some rare rhenium polyhydrides supported by phosphites are prepared and characterized using the cage phosphite ligand P(OCH[sub 2])[sub 3] CEt.

• Research Organization: Yale Univ., New Haven, CT (United States)
• OSTI ID: 6930912
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HYDROGEN COMPLEXES
ACTIVATION ENERGY
CHEMICAL REACTIONS
MOLECULAR STRUCTURE
TRANSITION ELEMENT COMPLEXES
CATALYTIC EFFECTS
CHEMICAL PREPARATION
CHEMICAL PROPERTIES
HYDRIDES
RHENIUM COMPLEXES
RUTHENIUM COMPLEXES
TUNGSTEN COMPLEXES
COMPLEXES
ENERGY
HYDROGEN COMPOUNDS
SYNTHESIS
400201* - Chemical & Physicochemical Properties