Hydrolysis of phosphate diesters with copper(II) catalysts
Hydrolysis of phosphate diesters (4-NO/sub 2/C/sub 6/H/sub 4/O)/sub 2/PO/sub 2/Na (1) and (4-NO/sub 2/C/sub 6/H/sub 4/O)(CH/sub 3/CH/sub 2/O)PO/sub 2/Li (2) is catalyzed by Cu(bpy)/sup 2 +/ (bpy = 2,2'-bipyridine) in aqueous solution at 75/degrees/C in the pH range 5.8-8.3. Greater than 1000 turnovers and 200 turnovers per Cu(bpy)/sup 2 +/ are observed in the hydrolysis of 1 and 2, respectively. Catalytic rate enhancements of the hydrolysis of 1 and 2 by 1 x 10/sup -3/ M Cu(bpy)/sup 2 +/ at pH 6.5 over spontaneous hydrolysis under the same conditions without catalyst are 2000 and 150, respectively. The hydrolysis of copper-bound 2 proceeds 6300-fold more rapidly (pH 7.85) than hydrolysis of 2 in the absence of catalyst. Kinetics for the Cu(bpy)/sup 2 +/-catalyzed hydrolysis of 2 are examined in detail. Reaction pathways are proposed. Labeling studies in /sup 18/OH/sub 2/ show no incorporation of /sup 18/O into p-nitrophenol. A single /sup 18/O label incorporates into the (C/sub 2/H/sub 5/O)PO/sub 3//sup 2 -/ product. Several simple transition-metal complexes promote the catalytic hydrolysis of phosphate diesters 1 and 2, although none are as effective as Cu(bpy)/sup 2 +/. Second-order rate constants for Cu(bpy)/sup 2 +/-promoted hydrolysis in the series of 4-nitrophenyl phosphate esters (triester, diester (anion), monoester (dianion)) vary by only a factor of 60 in contrast to those for the reaction of these phosphate esters with anionic nucleophiles in the absence of metal catalysts, which show large differences in second-order rate constants (> 10/sup 3/) between each ester in the series. 54 references, 5 figures, 6 tables.
- Research Organization:
- Univ. of California at San Diego, La Jolla (USA)
- OSTI ID:
- 6181204
- Journal Information:
- Inorg. Chem.; (United States), Vol. 27:19
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BIPYRIDINES
CATALYTIC EFFECTS
COPPER COMPLEXES
PHOSPHORIC ACID ESTERS
HYDROLYSIS
CATALYSIS
EXPERIMENTAL DATA
LABELLED COMPOUNDS
OXYGEN 18
AZINES
CHEMICAL REACTIONS
COMPLEXES
DATA
DECOMPOSITION
ESTERS
EVEN-EVEN NUCLEI
HETEROCYCLIC COMPOUNDS
INFORMATION
ISOTOPES
LIGHT NUCLEI
LYSIS
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OXYGEN ISOTOPES
PYRIDINES
SOLVOLYSIS
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
400202 - Isotope Effects
Isotope Exchange
& Isotope Separation