Symmetry-based 29Si dipolar recoupling magic angle spinning NMR spectroscopy: a new method for investigating three-dimensional structures of zeolite frameworks

摘要: A new 29Si solid-state MAS NMR experiment is described for investigating the framework structures of pure silica zeolites. The symmetry-based homonuclear dipolar recoupling sequence SR26411 has been incorporated into a two-dimensional to probe Si-O-Si bonding connectivities and long-range Si-Si distances in zeolite frameworks. This shown have number advantages over J-coupling-based INADEQUATE experiment. For clathrasil Sigma-2, it demonstrated that there excellent agreement between experimental double-quantum build-up curves obtained from series correlation spectra simulated which consider all out 8 A. result suggests this could be used solve frameworks with unknown structures.