Catalytic hydrolysis of a phosphate triester by tetracoordinated zinc complexes

Journal Article · Wed Apr 30 00:00:00 EDT 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00269a041· OSTI ID:5658552

Gellman, S H; Petter, R; Breslow, R

A zinc complex of a tetraaza macrocycle catalyzes the hydrolysis of diphenyl p-nitrophenyl phosphate is aqueous acetonitrile. The principal products derive from loss of p-nitrophenol, but some alternative hydrolysis with loss of phenol is also observed. Kinetic studies show that the catalytic zinc species is a zinc hydroxide complex with a pK/sub a/ of 8.7 (or its kinetic equivalent). The greater kinetic effectiveness of this weak base than of free hydroxide ion itself, on a molar basis, indicates a bifunctional mechanism in which bound hydroxide acts as a nucleophile, while zinc acts as a electrophilic catalyst. This process is relatively strainless at phosphorus, in contrast to reactions at carbon with the same species in which the bifunctional mechanism would be strained and is not seen. A derivative of the zinc macrocycle complex carrying a long alkyl chain was examined as the catalyst for the same substrate in a Brij micelle. This lipophilic complex is even more effective, acting as a zinc hydroxide species with pK/sub a/ = 9.1, but in the micellar reaction there are contributions from kinetic terms higher than first order in the zinc complex. Thus, in this system, catalysis by aggregates is apparently also occurring.

• Research Organization: Columbia Univ., New York, NY
• OSTI ID: 5658552
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 108:9
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ESTERS
HYDROLYSIS
CATALYSIS
PHOSPHATES
ZINC COMPLEXES
CATALYTIC EFFECTS
CATALYSTS
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
PH VALUE
CHEMICAL REACTIONS
COMPLEXES
DATA
DECOMPOSITION
INFORMATION
KINETICS
LYSIS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
REACTION KINETICS
SOLVOLYSIS
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)