The delivery of pharmaceuticals into the human body or the storage of
voluminous quantities of gas molecules could now be better controlled, thanks
to a study by University
of Pittsburgh
researchers. In a paper published online in Nature Communications, a team of chemists and colleagues from
Pitt’s Kenneth P. Dietrich School of Arts and Sciences and the Pitt School of
Medicine and Northwestern and Durham
universities have posed an alternative approach toward building porous
materials.
Working with metal-organic frameworks—crystalline compounds comprising
metal-cluster vertices linked together by organic molecules to form 1D, 2D, or
3D porous structures—researchers addressed changing the size of the vertex (the
metal cluster) rather than the length of the organic molecule links, which
resulted in the largest metal organic framework pore volume reported to date.
“Think of this the way you imagine Tinkertoys,” said Nathaniel Rosi,
principal investigator and assistant professor in Pitt’s Department of
Chemistry in the Dietrich
School. “The metal
clusters are your joints, and the organic molecules are your linkers. In order
to build a highly open structure with lots of empty space, you can increase the
linker length or you can increase the size of the joint. We developed chemistry
to make large joints, or vertices, and showed that we could link these together
to build a material with extraordinarily large pores for this class of
materials.
“Essentially, we’re like architects. We first make a blueprint for a target
material, and we then select our building blocks for construction,” added Rosi. “We develop methods for designing structures and controlling the assembly of
these structures on a molecule-by-molecule basis.”
Rosi and Jihyun An, who graduated with a PhD degree in chemistry from Pitt
in 2011 and is lead author of the paper, said this new approach could have an
impact on storing large quantities of gas such as carbon dioxide or methane, an
important development for alternative energy, or large amounts of drug
molecules, which could impact the drug-delivery field.
