Development of Mixed metal Metal-organic polyhedra networks, colloids, and MOFs and their Pharmacokinetic applications

Nazir Ahmad,Muhammad Danish,Adeel H Chughtai,Francis Verpoort,Zhang Gaoke,Hussein A Younus,Kristof Van Hecke

doi:10.1038/s41598-017-00733-4

Abstract

SummaryThe coordination networking of discrete metal-organic polyhedra (MOPs) involving different ligands as well as metals is a challenging task due to the features of limited solubility and chemical stability of these polyhedra. An unusual approach, ligand-oriented polyhedral networking via click chemistry and further metal coordination is reported here. An alkyne decorated Cu(II)-MOP self-catalyzes the regioselective click reaction (1,3-dipolar cycloaddition) using azide-functionalized ligands under unconventional reaction conditions. Introducing new metal ions, M(II), interlinks the carboxylic groups on the MOP surfaces creating coordination networks. On the other hand, exposure of the respective individual ligand components in the presence of Cu(II) promotes an in-situ click reaction along with metal coordination generating a new 3D-framework. These materials demonstrated a high drug hosting potential exhibiting a controlled progressive release of anticancer (5-flourouracil) and stimulant (caffeine) drugs in physiological saline at 37 °C. These innovative and unconventional MOP networks provide a significant conceptual advance in understanding.

Highlights

To extend the nanometer sized MOPs using a coordination process, two possible options are available either through the connection of vertices[12,13,14] or edges
In the case of organic bridging linker N1, the CuMOP surface contains 24 carboxylic (–COOH) groups which become activated for further coordination with the addition of a metal (Fig. 1A)
The features of the work contain unprecedented results e.g., (i) self-catalysis of the coordination cage creating new reaction sites for (ii) further coordination with more/different metals leading to exceptional coordination networks

Summary

Introduction

To extend the nanometer sized MOPs using a coordination process, two possible options are available either through the connection of vertices (metallic nodes)[12,13,14] or edges (ligand). At the MOP periphery, as compared to the bridging ligands, metal sites are blocked by coordinated solvent(s). MOPs have a higher number of ligand bridges exposed at the surface than that of the metallic nodes (e.g. M2(COO−)[4] or the coordination spheres having cage formula MnL2n)[15]. Introducing a new covalent functionalization containing electron (e−) donor group(s) over the supramolecular cages in the presence of M(II) ions can interconnect these precursors giving rise to a novel porous coordination network. This approach would create a network in which. Materials based on unconventional supramolecular coordination networking can be engineered

Methods

Results

Conclusion