Mechanistic studies of phosphorus-oxygen bond cleavages in group 7 dinuclear complexes of 2-pyridyl dimethylphosphinite
Dinuclear chelates fac-L/sub 2/Re(CO)/sub 3/(M(CO)/sub 5/) (L/sub 2/ = 2-pyridyl dimethylphosphinite, 2, M = Re; 3, M = Mn) rearranged in benzene at 80/sup 0/C to provide the corresponding (CO)/sub 4/Re(..mu..OPYR)(..mu..-PMe/sub 2/)M(CO)/sub 4/ derivatives 5 (M = Re) and 6 (M = Mn) in 95 and 94% yield, respectively. The rearrangements exhibited first-order kinetics to > 3 half-lives and displayed the following kinetic parameters: M = Re, ..delta..H/sup + +/ = 24.2 +- 1.8 kcal/mol and ..delta..S/sup + +/ = -10 +- 5 eu; M = Mn, ..delta..H/sup + +/ = 22.2 +- 0.7 kcal/mol and ..delta..S/sup + +/ = -11 +- 2 eu. The reaction rates and the products formed were unaffected by added CO, methlating agents, or triphenylphospine. In the presence of carbon tetrachloride, the rearrangements afforded mixtures of the P-O cleavage products (5 or 6) and fac-(CO)/sub 6/L/sub 2/ReCl. Crossover studies showed the rearrangements of 2 and 3 to occur with statistically significant inter- and intramolecular components. The results are discussed in light of mechanisms involving CO dissociation, homo- and heterolytic metal-metal bond cleavage, and a novel dyotropic rearrangement.
- Research Organization:
- Cornell Univ., Ithaca
- OSTI ID:
- 5658565
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 108:9; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
AZINES
CATALYSTS
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
DATA
DEACTIVATION
DERIVATIZATION
ELEMENTS
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
KINETICS
MANGANESE COMPLEXES
MEDIUM TEMPERATURE
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN
PHOSPHINES
PHOSPHORUS
PHOSPHORUS COMPOUNDS
PYRIDINES
REACTION KINETICS
RHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES