A route to high surface area, porosity and inclusion of large molecules in crystals

Abstract

One of the outstanding challenges in the field of porous materials is the design and synthesis of chemical structures with exceptionally high surface areas¹. Such materials are of critical importance to many applications involving catalysis, separation and gas storage. The claim for the highest surface area of a disordered structure is for carbon, at 2,030 m² g^-1 (ref. 2). Until recently, the largest surface area of an ordered structure was that of zeolite Y, recorded at 904 m² g^-1 (ref. 3). But with the introduction of metal-organic framework materials, this has been exceeded, with values up to 3,000 m² g^-1 (refs 4–7). Despite this, no method of determining the upper limit in surface area for a material has yet been found. Here we present a general strategy that has allowed us to realize a structure having by far the highest surface area reported to date. We report the design, synthesis and properties of crystalline Zn₄O(1,3,5-benzenetribenzoate)₂, a new metal-organic framework with a surface area estimated at 4,500 m² g^-1. This framework, which we name MOF-177, combines this exceptional level of surface area with an ordered structure that has extra-large pores capable of binding polycyclic organic guest molecules—attributes not previously combined in one material.