A study on a primitive artificial esterase model: Reactivity of a calix[4]resorcinarene bearing carboxyl groups
Yükleniyor...
Tarih
2008
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The host molecule octacarboxymethyl calix[4]resorcinarene 1 catalyses the hydrolysis of substituted phenyl N-methylpyridinium-4-carboxylate esters 3a-f by complexation followed by intracomplex reaction via an anhydride intermediate. The reactivity in the presence of 1 is higher than that of the background at low pH; at high pH an inversion of reactivity occurs, the background becomes predominant since the host inhibits hydrolysis of the esters. The reactivity of esters 3a-f complexed with the host suffers little change in effective charge on the phenolic oxygen (-0.15 units) in contrast with the changes observed in alkaline hydrolysis (-0.28 units) and in the hydrolysis of the model monoaryl glutarate esters (-1.02 units). The less negative effective charge in the transition state for host 1 catalysis compared with that in the glutarate case is ascribed to stronger solvation by water molecules in the complex compared with that due to water molecules in the bulk solvent.
Açıklama
Anahtar Kelimeler
Calixresorcinarenes, Catalysis, Ester hydrolysis, Molecular receptors
Kaynak
Journal of Physical Organic Chemistry
WoS Q Değeri
Scopus Q Değeri
Q3
Cilt
21
Sayı
6
Künye
Cevasco, G., Galatini, A., Pirinççioğlu, N., Thea, S. ve Williams, A. (2008). A study on a primitive artificial esterase model: Reactivity of a calix[4]resorcinarene bearing carboxyl groups. Journal of Physical Organic Chemistry, 21(6), 498-504.
