A set of two-dimensional solid-state NMR experiments providing topological information for structure refinement of TMP-GaPO

Crystallography and NMR: An Overview

“…NMR demonstrated 36 unequivocally that there was exchange between the two forms (temporal disorder), and a combination of selective population inversion and bandshape analysis enabled the thermodynamic parameters for the exchange to be derived. Additionally, two-dimensional work provided the relative orientations of 15 N shielding principal axes in the two forms (consistent with the diffraction data).…”

“…It is particularly important for ceramic materials and zeolites because of the electronic similarity of oxygen and nitrogen and of the SiN and AlO pairs of atoms. Thus, 15 N NMR has been used 37 to determine the ordering of anionic elements (nitrogen and oxygen) in J -phase yttrium silicon oxynitride, Y 4 Si 2 O 7 N 2 .…”

Crystalline oxyfluorinated open-framework compounds: Silicates, metal phosphates, metal fluorides and metal-organic frameworks (MOF)

“…A structural correlation of the SBU type could be made as a function of the pK a values of the different diamines [46]. Fluorine may be also involved in a terminal bond with shorter Ga-F distances as found in GaPO 4 -CJ2 [73] (1.903 Å ), TMP-GaPO [74] (1.79 Å ), Mu-3 [58] (1.824-1.862 Å ), Mu-15 [60] (1.86 Å ) Mu-23 [75] (1.854-1.885 Å ) and Mu-28 [76] (1.80-1.86 Å ). Due to its higher electronegativity, it preferentially interacts via strong hydrogen bonds with the ammonium groups of the amine molecules.…”

A structure refinement strategy for NMR crystallography: An improved crystal structure of silica-ZSM-12 zeolite from 29Si chemical shift tensors

“…These concepts have recently been formalized [27] and NMR experiments to identify the local site symmetry have been presented [28]. Two-dimensional (2D) correlation experiments, in which proximities and connectivities between atoms can be established, may also be employed to identify possible space groups [29], to aid in assignment of the NMR resonances [13,[30][31][32][33][34][35][36][37][38][39], or to derive structural models [7,8]. The distance information provided by solid-state NMR can be used to derive or constrain structural models [5,6,[40][41][42] in combination with other methods.…”