Supramolecular Complexes Formed by the Self-assembly of Hydrophobic Bis(Zn²⁺-cyclen) Complexes, Copper, and Di- or Triimide Units for the Hydrolysis of Phosphate Mono- and Diesters in Two-Phase Solvent Systems (Cyclen=1,4,7,10-Tetraazacyclododecane)

抄録

We previously reported on supramolecular complexes 4 and 5, formed by the 4 : 4 : 4 or 2 : 2 : 2 assembly of a dimeric zinc(II) complex (Zn₂L¹) having 2,2′-bipyridyl linker, dianion of cyanuric acid (CA) or 5,5-diethylbarbituric acid (Bar), and copper(II) ion (Cu²⁺) in an aqueous solution. The supermolecule 4 possesses Cu₂(μ-OH)₂ centers and catalyzes hydrolysis of phosphate monoester dianion, mono(4-nitrophenyl)phosphate (MNP), at neutral pH. In this manuscript, we report on design and synthesis of hydrophobic supermolecules 9 and 10 by 4 : 4 : 4 and 2 : 2 : 2 self-assembly of hydrophobic Zn₂L² and Zn₂L³ containing long alkyl chains, CA or Bar, and Cu²⁺ and their phosphatase activity for the hydrolysis of MNP and bis(4-nitrophenyl)phosphate (BNP) in two-phase solvent systems. We assumed that the Cu₂(μ-OH)₂ active sites of 9 and 10 would be more stable in organic solvent than in aqueous solution and that product inhibition of the supermolecules might be avoided by the release of HPO₄²⁻ into the aqueous layer. The findings indicate that 9 and 10 exhibit phosphatase activity in the two-phase solvent system, although catalytic turnover was not observed. Furthermore, the hydrolysis of BNP catalyzed by the hydrophobic 2 : 2 : 2 supermolecules in the two-phase solvent system is described.