Mechanistic insights into templated materials synthesis
The importance of ordered micro-and mesoporous to our contemporary technological society was discussed in a recent issue of Current Opinion in Colloid and Interface Science along with seven reviews on various aspects concerning the mechanistic elements of the synthesis of these materials with emphasis on analytical and synthesis possibilities. This issue continues the series of reviews dealing with the current understanding of the mechanistic details of "templated" porous materials synthesis covering both zeolites and mesoporous materials. We have gathered two additional opinions on the contributions of NMR spectroscopy and in-situ X-ray diffraction to the understanding of nanoporous materials synthesis and one opinion on morphological control of mesoporous materials. The reader should benefit from contrasting the findings reported in these papers to the contributions presented in the previous issue.
The comprehensive review by Epping and Chmelka covers contributions of NMR spectroscopy to zeolites, ALPOs, SAPOs as well as mesostructured materials, with a focus on molecular insights from magnetic resonance spectroscopy on nucleation and growth of zeolites and inorganic mesoporous solids. The power of magnetic resonance spectroscopy for elucidating the molecular interactions and processes in complicated solutionand solid-state systems forms the basis for the usefulness of this technique for detailed studies of synthesis and structures of porous materials. New and detailed insights on the formation mechanisms of these important materials have emanated from information provided by state-of-the-art NMR and EPR techniques in conjunction with state-of-the-art syntheses and in combination with diffraction measurements and theoretical calculations.
Further understanding of growth processes using in-situ powder diffraction is reviewed by Norby. The increased availability of high intensity synchrotron sources and the improved sample handling techniques have resulted in the ability to follow in-situ the crystallization of microporous materials. The possibilities and limitations of the present stateof-the-art in-situ methods using especially energy and angular dispersive synchrotron X-ray powder diffraction are described and discussed with examples of in-situ studies of microporous materials synthesis. Despite large progress in this area considerable challenges remain in interpreting results to elucidate nucleation and crystallization mechanisms in detail.