Supramolecular phosphatases formed by the self-assembly of the bis(Zn2+-cyclen) complex, copper(II), and barbital derivatives in water

• Published in: Chemistry - An Asian Journal
• Main Author: Zulkefeli M.; Hisamatsu Y.; Suzuki A.; Miyazawa Y.; Shiro M.; Aoki S.
• Format: Article
• Language: English
• Published: John Wiley and Sons Ltd 2014
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920710764&doi=10.1002%2fasia.201402513&partnerID=40&md5=869cbe4ffee981c16c29c7a0ebd5ab64

In our previous paper, we reported that a dimeric Zn2+ complex with a 2,2′-bipyridyl linker (Zn2L1), cyanuric acid (CA), and a Cu2+ ion automatically assemble in aqueous solution to form 4:4:4 complex 3, which selectively catalyzes the hydrolysis of mono(4-nitrophenyl)phosphate (MNP) at neutral pH. Herein, we report that the use of barbital (Bar) instead of CA for the self-assembly with Zn2L1 and Cu2+ induces 2:2:2 complexation of these components, and not the 4:4:4 complex, to form supramolecular complex 6a, the structure and equilibrium characteristics of which were studied by analytical and physical measurements. The finding show that 6a also accelerates the hydrolysis of MNP, similarly to 3. Moreover, inspired by the crystal structure of 6a, we prepared barbital units that contain functional groups on their side chains in an attempt to produce supramolecular phosphatases that possess functional groups near the Cu2(μ-OH)2 catalytic core so as to mimic the catalytic center of alkaline phosphatase (AP). © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.