Peptide-Mediated Synthesis of Zeolitic Imidazolate Framework-8: Effect of Molecular Hydrophobicity, Charge Number and Charge Location.

Maozhang Tian,Jiaming Xuan,Wentao Wang,Qun Zhang,Xinyuan Zou,Meiwen Cao,Xi Chen,Desheng Ma

doi:10.3390/nano11102665

Abstract

Three amphiphilic peptides with varied molecular hydrophobicity, charge number and charge location have been designed as regulators to modulate the crystal growth of zeolitic imidazolate framework-8 (ZIF-8). All three peptides can interact with ZIF-8 to inhibit {100} facet growth and produce truncated cubic crystals. The peptide’s molecular hydrophobicity plays a dominant role in defining the final morphology and size of the ZIF-8 crystals. The peptides with less charge and higher hydrophobicity can promote nuclei formation and crystal growth to give smaller ZIF-8 crystals. However, the charge located in the center of the molecular hydrophobic region has little effect on the crystal nucleation and growth due to the shielding of its charge by molecular aggregation. The study provides insights into the effect of molecular charge and hydrophobicity on ZIF-8 crystal growth and is helpful for guiding the molecular design for regulating the synthesis of metal-organic framework materials.

Highlights

Metal-organic frameworks (MOFs) are a novel class of crystallized porous materials that are self-assembled by metal clusters as connecting points and organic ligands as bridging molecules to form a two- or three-dimensional framework through coordination bonds [1,2,3,4,5,6,7]
We mainly demonstrated the effect of molecular hydrophobicity on the regulation of the zeolitic imidazolate framework-8 (ZIF-8) crystal growth
The peptide molecular hydrophobicity plays a dominant role in defining the final morphology of the ZIF-8 crystals

Summary

Introduction

Metal-organic frameworks (MOFs) are a novel class of crystallized porous materials that are self-assembled by metal clusters as connecting points and organic ligands as bridging molecules to form a two- or three-dimensional framework through coordination bonds [1,2,3,4,5,6,7]. Zeolitic imidazolate framework-8 (ZIF-8) is one typical kind of MOF that is comprised of zinc ions and 2-methylimidazole [34,44,45,46] It is characterized by high porosity and a large surface area and has great advantages in the encapsulation and delivery of functional species [13,16,47,48,49,50]. It has high biocompatibility, excellent stability under physiological conditions and good responsiveness towards acidic conditions.

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Discussion

Conclusion