Charge-transfer interactions between fullerenes and a mesoporous tetrathiafulvalene-based metal-organic framework.

Manuel Souto,Aron Walsh,Joaquín Calbo,Samuel Mañas-Valero,Guillermo Mínguez Espallargas

doi:10.3762/bjnano.10.183

Abstract

The design of metal–organic frameworks (MOFs) incorporating electroactive guest molecules in the pores has become a subject of great interest in order to obtain additional electrical functionalities within the framework while maintaining porosity. Understanding the charge-transfer (CT) process between the framework and the guest molecules is a crucial step towards the design of new electroactive MOFs. Herein, we present the encapsulation of fullerenes (C60) in a mesoporous tetrathiafulvalene (TTF)-based MOF. The CT process between the electron-acceptor C60 guest and the electron-donor TTF ligand is studied in detail by means of different spectroscopic techniques and density functional theory (DFT) calculations. Importantly, gas sorption measurements demonstrate that sorption capacity is maintained after encapsulation of fullerenes, whereas the electrical conductivity is increased by two orders of magnitude due to the CT interactions between C60 and the TTF-based framework.

Highlights

Metal–organic frameworks (MOFs), which are crystalline porous materials constructed from metallic nodes and organic linkers, have been a major breakthrough in chemistry in the last decades [1,2]
We have reported a hierarchical and highly stable TTF-based metal–organic frameworks (MOFs), named MUV-2, which is based on the 6-connected trimeric cluster [Fe3(μ3O)(COO)6] as secondary building unit (SBU) and tetratopic tetrathiafulvalene-tetrabenzoate (TTFTB4−) ligands
The powder X-ray diffraction (PXRD) pattern of C60@MUV-2 shows that the principal peak remains at 3.4° confirming that crystallinity is maintained after encapsulation of C60 and removal of the solvent (Figure 2)

Summary

Introduction

Metal–organic frameworks (MOFs), which are crystalline porous materials constructed from metallic nodes and organic linkers, have been a major breakthrough in chemistry in the last decades [1,2]. Gas sorption measurements demonstrate that sorption capacity is maintained after encapsulation of fullerenes, whereas the electrical conductivity is increased by two orders of magnitude due to the CT interactions between C60 and the TTF-based framework.

Results

Conclusion