Tuning the Conductivity of Hexa-Zirconium(IV) Metal-Organic Frameworks by Encapsulating Heterofullerenes

Electrical conductivity in metal-organic frameworks (MOFs) has a great potential for energy storage applications and electrocatalysis. Zirconium-based MOFs such as NU-901 and NU-1000 have a low electrical conductivity due to the redox innocence of Zr-oxo bonds. Recently, it has been shown that the electrical conductivity of NU-901 can be increased by 11 orders of magnitude by physically encapsulating fullerene (C60) in its diamond pore. This effect is due to the host-guest interaction between the electron-rich 1,3,6,8-tetrakis(p-benzoate)pyrene (TBAPy4-) organic linkers of NU-901 (host) and the electron-poor fullerene (guest). Herein, we used density functional theory to study heterofullerene (C59X; X = B, Al, Ga, In, Si, Ge, and Sn) encapsulation in NU-901. Our study suggests that encapsulated heterofullerenes enhance the electrical conductivity of the NU-901 MOF even further than C60.