91福利

Flexible Frameworks: Novel Geometries in Zeolites and Framework Encapsulated Nanomaterials 

In this talk I will present two aspects of framework studies. Firstly, I will discuss rational search for zeolites among hypothetical structures, and secondly, development of novel framework encapsulated nanomaterials. Today synthetic zeolites are the most important catalysts in petrochemical refineries because of their high internal surface areas and catalytic and chemical properties. There have been considerable efforts to synthesize new zeolites with specific pore geometries, to add to ~190 available at present. Millions of hypothetical structures have been generated on the basis of energy minimization, and there is an ongoing search for criteria capable of predicting new zeolite structures. We have recently discovered a new property of realizable zeolites – the flexibility window – which is a theoretical measure
which can provide a valuable selection criterion when evaluating hypothetical zeolite framework structures as potential synthetic targets. I will show that the flexibility window is a necessary structural feature that enables zeolite synthesis. Another application where pore geometries have a big role is design of encapsulated nanomaterials. Many alkali metals and alkali metal hydrides/amides are very strong and important reagents and catalysts in organic chemistry. Unfortunately, they are  air-sensitive, pyrophoric, harmful and sometimes toxic, in short – unsafe to use in the laboratory conditions. Encapsulation of such material in abundant, not-toxic and not-reactive and open framework can lead to much safer handling and greener chemistry. We have recently produced a metal hydride nanomaterial encapsulated in silica, which retains its reactive properties, but is not pyrophoric in dry air. The success of this material can lead to new way of developing nanomaterials by encapsulating them in a protective framework for safer handling.