Reactions of ethylene, allene and acetylene with ditungsten alkoxide and hydrido alkoxide compounds: Studies of structure, bonding and reactivity

Thesis/Dissertation · Tue Dec 31 23:00:00 EST 1991

OSTI ID:7046115

Chacon, S T

The preparation and dynamic solution behavior of W[sub 2]([mu]-H)(O-c-C[sub 5]H[sub 9])[sub 7](HNMe[sub 2]) are described and the reactions of W[sub 2](OR)[sub 6] and W[sub 2] ([mu]-H)(OR)[sub 7]L compounds with various unsaturated molecules are reported. The products, W[sub 2] (O-t-Bu)[sub 6](C[sub 3]H[sub 4]) (1), W[sub 2](O-t-Bu)[sub 6](C[sub 3]H[sub 4])[sub 2] and W[sub 2](O-t-Bu)[sub 6](C[sub 3]H[sub 4])(CO)[sub 2] were obtained from the reactions of W[sub 2](O-t-Bu)[sub 6] with allene and CO. Compound 1 contains an allene ligand in an unprecedented bonding mode. The two perpendicular [pi]-systems of the allene ligand are completely rehybridized such that the four allenic protons lie essentially in the same plane, rather than in two planes at 90[degrees] to one another. The other two products exhibit two other bonding modes, [eta][sup 2]-allene and [mu],[eta][sup 1],[eta][sup 3]-allene. The compound W[sub 2](OCH[sub 2]-t-Bu)[sub 6](C[sub 2]H[sub 4])[sub 2] (2) was obtained from the reaction of ethylene with W[sub 2](OCH[sub 2]-t-Bu)[sub 6], and has an unprecedented structure containing four bridging alkoxide ligands. The bonding in 2 was studied using the molecular orbital calculational methods of Fenske-Hall and Extended Hueckel Theory. Solution behavior indicated exchange of cis ethylene protons and the mechanism of the fluxional behavior is discussed. The hydride ligand in W[sub 2]([mu]-H)(OR)[sub 7]L compounds was found to migrate onto ethylene and ketone ligands to form ethyl and alkoxide ligands, in W[sub 2](O-c-C[sub 5]H[sub 9])[sub 7](C[sub 2]H[sub 5])([eta][sup 2]-C[sub 2]H[sub 4]) and W[sub 2](O-c-C[sub 5]H[sub 9])[sub 8]([eta][sup 2]-O-c-C[sub 5]H[sub 8]), respectively. The reaction of the hydrido alkoxide compounds with allene leads to W[sub 2](O-c-C[sub 5]H[sub 9])[sub 8](C[sub 3]H[sub 4]) which presumably arises from intermolecular ligand scrambling. The reaction with acetylene at low temperature is described, as well as other reactions.

• Research Organization: Indiana Univ. Foundation, Bloomington, IN (United States)
• OSTI ID: 7046115
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACETYLENE
ALKENES
ALKOXIDES
ALKYNES
ALLENE
CHEMICAL BONDS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
DIENES
ETHYLENE
HYDROCARBONS
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
POLYENES
REFRACTORY METAL COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS