ISSN:
0894-3230
Keywords:
Organic Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Although the cyclen - Co(III) complex has exhibited amongst the greatest rate accelerations in acyl and phosphoryl transfer reactions, this catalytic unit has not been used previously in the design of an artificial metalloenzyme. For this study, β-cyclodextrin derivatives of cyclen - Co(III) with attachments to the primary and secondary sides of the cyclodextrin torus were synthesized. The primary-side cyclodextrin-cyclen-Co(III) conjugate accelerates the hydrolysis of p-nitrophenylacetate by a factor of 1000 (pH 7.0, 25°C) in comparison with the water-catalyzed reaction. Maximum reactivity occurs at pH 7, consistent with the known pKa values and hypothesised mechanism of action of Co(III) complexes. The secondary-side cyclodextrin-cyclen-Co(III) conjugate is less reactive towards p-nitrophenylacetate hydrolysis under saturating conditions. Reactivities towards an azide, a phosphonate and a phosphate triester were in each case less than five times greater than the buffer-catalyzed rate.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/poc.610050817
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