Reactions of alkynes having electron-withdrawing substituents with Re[sub 2](CO)[sub 9](NCMe). Formation of trans dimetalated olefins by alkyne insertion into an Re-Re bond

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Organometallics; (United States)

DOI:https://doi.org/10.1021/om00028a048· OSTI ID:6250706

Adams, R D; Chen, L; Wu, W ^[1]

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1. Univ. of South Carolina, Columbia (United States)

The reaction of the dirhenium complex Re[sub 2](CO)[sub 9](NCMe), 1, with electrophilic alkynes, RC[quadruple bond]CCO[sub 2]R[prime], proceeds by displacement of the NCMe ligand and addition of the alkyne with insertion into the rhenium-rhenium bond to yield the dimetalated olefin complexes, Re(CO)[sub 4-][trans-[mu]-RC=C(CO[sub 2]R[prime])]Re(CO)[sub 5], R = H, R[prime] = Me, 2a, R = Me, 2b, and R = CO[sub 2]Et, R[prime] = Et, 2c, that have a trans stereochemistry at the C-C double bond. The carboxylate group is coordinated to one of the rhenium atoms through the ketonic oxygen atom to form a metallacycle. The reaction is insensitive to radical scavengers, solvent polarity, and light. The absence of crossover in a reaction of a mixture of labeled and unlabeled 1 is consistent with the insertion of the alkyne into the metal-metal bond by an intramolecular mechanism. Compound 2a was found to add CO (reversibly) to open the metallocycle and form the simple dimetalated olefin complex Re(CO[sub 5][trans-[mu]-HC=C(CO[sub 2]Me))]Re(CO)[sub 5], 3. When irradiated, 2a underwent a shift of the alkenyl hydrogen atom to the carboxylate-substituted carbon atom to form the carboxylate-substituted vinylidene complex Re[sub 2](CO)[sub 8][[mu]C=CH(CO[sub 2]Me)], 4, in which the ketonic oxygen atom of the carboxylate group is coordinated to one of the metal atoms. The metal-metal bond in 4 was cleaved (reversibly) by addition of CO at 1 atm/25[degrees]C to yield the complex Re[sub 2](CO)[sub 9][[mu]-C=CH(CO[sub 2]Me)], 5, and under a high pressure of CO (1000 psi/100[degrees]C), compound 5 underwent a CO insertion (reversible) into one of the Re-C bonds to form the complex Re(CO)[sub 4][[mu]O=CC=CH(CO[sub 2]/Me)]Re(CO)[sub 5], 6. Compounds 1, 2a and 3-6 were characterized by single-crystal X-ray diffraction analysis. Crystal data are provided. 21 refs., 6 figs., 6 tabs.

• OSTI ID: 6250706
• Journal Information: Organometallics; (United States), Journal Name: Organometallics; (United States) Vol. 12:4; ISSN ORGND7; ISSN 0276-7333
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
ALKYNES
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
COMPLEXES
DATA
DIFFRACTION
EXPERIMENTAL DATA
HYDROCARBONS
INFORMATION
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
RESONANCE
RHENIUM COMPLEXES
SCATTERING
TRANSITION ELEMENT COMPLEXES
X-RAY DIFFRACTION