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A Multinuclear NMR Study of Six Forms of AlPO-34: Structure and Motional Broadening
- Source :
- The Journal of Physical Chemistry C. 121:1781-1793
- Publication Year :
- 2017
- Publisher :
- American Chemical Society (ACS), 2017.
-
Abstract
- SEA would like to thank the Leverhulme Trust (F/00 268/BJ) and EPSRC for computational support through the Collaborative Computational Project on NMR Crystallography (CCP-NC), via EP/M022501/1). SEA would also like to thank the Royal Society and Wolfson Foundation for a merit award. MA and RIW would like to acknowledge financial support from the EPSRC (EP/C516591), as would SW (GR/T23824). The research data (and/or materials) supporting this publication can be accessed at DOI: 10.17630/a6d6d27b-a8f0-46cb-8e6b-2c9a344e86b7. We report a study of the CHA-type aluminophosphate AlPO-34, prepared with six different structure-directing agents (SDAs): piperidine (pip), morpholine (mor), pyridine (pyr), 1,4,8,11-tetraazacyclotetradecane (cyclam), 1,3-dimethylimidazolium (dmim) chloride and 1-ethyl-3-methylimidazolium (emim) bromide. Using a combination of solid-state NMR spectroscopy, periodic density functional theory (DFT) calculations and synchrotron X-ray diffraction, we show that, even in crystallographically well-ordered materials such as AlPO-34 with dmim as the SDA, local disorder may be present. For such disordered structures, where it is challenging to use DFT to assign NMR spectra, we show that the 31P isotropic chemical shift can be predicted accurately using the mean P-O bond length and P-O-Al bond angle, in an extension of previous work. Variable-temperature 27Al NMR reveals the presence of microsecond-timescale dynamics in all forms of AlPO-34, with two different motional regimes observed, depending on whether structural H2O is also present. H2O is detected in AlPO-34 prepared with mor as the SDA, although this material was previously reported as anhydrous, suggesting that this form of AlPO-34 may be hygroscopic despite the presence of the SDAs within the pores. Postprint
- Subjects :
- DAS
02 engineering and technology
Nuclear magnetic resonance spectroscopy
QD Chemistry
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
0104 chemical sciences
Surfaces, Coatings and Films
Electronic, Optical and Magnetic Materials
Bond length
NMR spectra database
chemistry.chemical_compound
Microsecond
Crystallography
General Energy
Molecular geometry
chemistry
Morpholine
Cyclam
Pyridine
QD
Physical and Theoretical Chemistry
0210 nano-technology
Subjects
Details
- ISSN :
- 19327455 and 19327447
- Volume :
- 121
- Database :
- OpenAIRE
- Journal :
- The Journal of Physical Chemistry C
- Accession number :
- edsair.doi.dedup.....e5142ba4c2eab0aa540be5db1f657101