Guest‐Adaptable and Water‐Stable Peptide‐Based Porous Materials by Imidazolate Side Chain Control

Alexandros P Katsoulidis,George R Darling,Dmytro Antypov,Neil G Berry,Matthew J Rosseinsky,Craig M Robertson,Carlos Martí-Gastaldo,Dave J Adams,Frédéric Blanc,Gary J Miller,John E Warren,John A Purton,Kyo Sung Park

doi:10.1002/anie.201307074

Abstract

The peptide-based porous 3D framework, ZnCar, has been synthesized from Zn2+ and the natural dipeptide carnosine (β-alanyl-L-histidine). Unlike previous extended peptide networks, the imidazole side chain of the histidine residue is deprotonated to afford Zn–imidazolate chains, with bonding similar to the zeolitic imidazolate framework (ZIF) family of porous materials. ZnCar exhibits permanent microporosity with a surface area of 448 m2 g−1, and its pores are 1D channels with 5 Å openings and a characteristic chiral shape. This compound is chemically stable in organic solvents and water. Single-crystal X-ray diffraction (XRD) showed that the ZnCar framework adapts to MeOH and H2O guests because of the torsional flexibility of the main His-β-Ala chain, while retaining the rigidity conferred by the Zn–imidazolate chains. The conformation adopted by carnosine is driven by the H bonds formed both to other dipeptides and to the guests, permitting the observed structural transformations.

Highlights

The peptide-based porous 3D framework, ZnCar, has been synthesized from Zn2+ and the natural dipeptide carnosine (b-alanyl-l-histidine)
We present a new peptide-based Metal–organic frameworks (MOFs), ZnCar·DMF, which is assembled from Zn2+ and carnosine (Car), a natural dipeptide with the molecular structure b-alanyl-l-histidine
ZnCar·DMF crystallizes in the chiral monoclinic space group P21 and its 3D structure is directed by the carnosine conformation (Figure 1 a), as the Zn cations connected to the histidine moiety define a plane and the residue of the Nterminal b-alanine is extended to the third dimension

Summary

Introduction

The peptide-based porous 3D framework, ZnCar, has been synthesized from Zn2+ and the natural dipeptide carnosine (b-alanyl-l-histidine). ZnCar·DMF crystallizes in the chiral monoclinic space group P21 and its 3D structure is directed by the carnosine conformation (Figure 1 a), as the Zn cations connected to the histidine moiety define a plane and the residue of the Nterminal b-alanine is extended to the third dimension.

Results

Conclusion