Solid-State NMR Spectroscopy of Half-Integer Spin Quadrupolar Nuclei at High Magnetic Field Strengths: A Continuing Study of Hydrochloride Salts and Zirconium Phosphates
EMSL Project ID
2619
Abstract
This proposal is an extension of two previous projects, one with which we have had success, and one upcoming, at Pacific Northwest National Laboratories. The earlier study focussed on characterizing the chlorine EFG and CS tensors of hydrochloride salts via 35 Cl solid-state NMR at 18.8 T. We propose to extend this work to include an in-depth study of a series of hydrochloride salts, including the salts of several amino acids and numerous pertinent pharmaceutical compounds. As well, the 35/37 Cl NMR of some microporous transition metal complexes will be investigated. The main objective of this work will be to more effectively establish the possible trend observed between the 35 Cl quadrupolar coupling constant (CQ) and the number of local hydrogen bonds. A thorough understanding of the relationship between structure and CQ in these systems may allow 35/37 Cl solid-state NMR to become an effective tool for structural characterization of hydrochloride salts. The time devoted to 91 Zr NMR studies will focus on compounds which are not readily available, and are currently being synthesized. We propose to continue our upcoming preliminary 91 Zr solid-state NMR studies of isotopically-enriched alkali-metal and alkaline-earth zirconium phosphates characterizing and tracking changes in the zirconium CS and EFG tensors. As well, we wish to determine the feasibility of performing natural-abundance 91 Zr solid-state NMR experiments at high fields with such compounds. For both the 35/37 Cl and 91 Zr solid-state NMR experiments, the highest possible magnetic fields are essential to facilitate the measurement of the CS tensors and to reduce the second-order quadrupolar broadening.
Project Details
Project type
Capability Research
Start Date
2002-10-01
End Date
2004-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members