COMPUTER-ASSISTED STUDY OF NANOSTRUCTURED MICROPOROUS MATERIALS

We report here the results of our computational studies on porous cata lysts to bring out the catalytic role played by nanostructures. We pre sent two typical case studies where the molecular dynamic (MD) and qua ntum chemical (QC) techniques have revealed the important structural a spects involved in the functioning of nanostructured microporous mater ials. The central role played by the exchanged metal cations of zeolit e A in the molecular sieving of nitrogen and oxygen was studied by MD calculations. The results indicated that the mobility of the exchanged cations which are dependent on temperature causes the separation of n itrogen and oxygen molecules. The real time visualization of the dynam ic behavior of the exchanged cations during the MD process aids the un derstanding of this intriguing process occurring inside the micropores of the zeolites. The controlled pore opening of hydrated VPI-5 molecu lar sieve by careful removal of water leads to a large one dimensional channel. The possibility of anchoring organometallics, namely porphyr ins with 'enzyme-like' active sites were studied using QC calculations . The analysis of the 3-d contours of electron density and molecular e lectrostatic potential maps corresponding to various porphyrin systems and the cluster models representing VPI-5 framework brought out the p robable locations for porphyrins inside VPI-5.