Oxygen atom transfer reactions to metal carbonyls. Kinetics and mechanism of CO substitution reactions of M/sub 3/(CO)/sub 12/ (M = Fe, Ru, Os) in the presence of (CH/sub 3/)/sub 3/NO
Reported are the rates of reaction and activation parameters for CO substitution reactions of M/sub 3/(CO)/sub 12/ (M = Fe, Ru, Os) with L (L = PPh/sub 3/, P(OPh)/sub 3/, AsPh/sub 3/) in the presence of (CH/sub 3/)/sub 3/NO. In aprotic solvents the reactions are too fast to follow by conventional spectroscopy, but the rates decrease with added protonic solvents. Reactions are readily monitored at room temperature in the mixed solvent CHCl/sub 3/-C/sub 2/H/sub 5/OH (V/v, 2:1), and the rates of reaction are inversely proportional to the concentration of C/sub 2/H/sub 5/OH. It is suggested that this is due to hydrogen bonding to give (CH/sub 3/)/sub 3/NO...HOC/sub 2/H/sub 5/, which is unreactive compared with the very reactive free (CH/sub 3/)/sub 3/NO at these reaction conditions. The rates of formation of M/sub 3/(CO)/sub 11/L are first-order in concentrations of metal cluster and of (CH/sub 3/)/sub 3/NO but zero-order in concentration of L. This suggests a mechanism that involves a nucleophilic attack of the O atom of (CH/sub 3/)/sub 3/NO on the C atom of a CO, accompanied by oxidation of CO to CO/sub 2/. Since CO/sub 2/ is a good leaving group, its departure from the metal clusters affords the active intermediates M/sub 3/(CO)/sub 11/. These then rapidly react with entering ligands to form the monosubstituted products M/sub 3/(CO)/sub 11/L. The rates of reaction decrease in the order F/sub 3/(CO)/sub 12/ > Ru/sub 3/(CO)/sub 12/ > Os/sub 3/(CO)/sub 12/, and an attempt is made to account for the observed relative rates.
- Research Organization:
- Lanzhou Univ. (China)
- OSTI ID:
- 7005243
- Journal Information:
- J. Am. Chem. Soc.; (United States), Vol. 110:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBONYLS
CHEMICAL REACTIONS
IRON COMPOUNDS
ORGANIC SOLVENTS
SOLVENT PROPERTIES
OSMIUM COMPOUNDS
RUTHENIUM COMPOUNDS
ABSORPTION SPECTROSCOPY
ACTIVATION ENERGY
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
LIGANDS
MEDIUM TEMPERATURE
OXYGEN
QUANTITY RATIO
REACTION INTERMEDIATES
ULTRAVIOLET SPECTRA
VISIBLE SPECTRA
DATA
ELEMENTS
ENERGY
INFORMATION
KINETICS
NONMETALS
NUMERICAL DATA
REACTION KINETICS
REFRACTORY METAL COMPOUNDS
SOLVENTS
SPECTRA
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties