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An Extended Study of Solid Molybdenum and Organometallic Magnesium Compounds using 95Mo and 25Mg Nuclear Magnetic Resonance Spectroscopy


EMSL Project ID
3366

Abstract

This proposal is an extension of two projects which involve the study of low frequency half-integer spin quadrupolar nuclei: 95Mo and 25Mg. Due to the unfavourable nuclear properties of these nuclei, molybdenum-95 (I = 5/2; N.A. = 15.92 %;  = 6.517 MHz; Q = -0.022 barn) and magnesium-25 (I = 5/2; N.A. = 10.00%;  = 6.121 MHz; Q = 0.20 barn), few NMR studies have been carried out in the solid state. During previous visits to the Pacific Northwest National Laboratories, we have been successful in acquiring solid-state NMR spectra for both 95Mo and 25Mg. The current proposal focuses on our continuing study of prototypal molybdenum compounds including a series of molybdate salts. Initial 95Mo NMR studies have allowed us to characterize the molybdenum NMR parameters for a piano-stool complex, octahedral complexes, and several molybdate salts. Our proposed 25Mg NMR work involves the characterization of magnesium organometallic complexes with cyclic polydentate ligands, namely, magnesium crown ethers. Previous success with Mg(15-crown-5)(OTf)2 has demonstrated that, with the use of high applied magnetic fields, high-quality 25Mg NMR spectra may be obtained. We intend to continue this work by analyzing an extended series of magnesium crown complexes with our end goal being the determination of the 25Mg NMR parameters of magnesium nuclei at the center of porphyrin rings. In addition to standard solid-state NMR techniques, such as static Hahn-echo and one-pulse experiments, we will be employing the quadrupolar-Carr-Purcell-Meiboom-Gill (QCPMG) pulse sequence.

Project Details

Project type
Capability Research
Start Date
2003-04-12
End Date
2004-04-26
Status
Closed

Team

Principal Investigator

Roderick Wasylishen
Institution
University of Alberta

Team Members

Kristopher Ooms
Institution
The King's University College

Michelle Forgeron
Institution
University of Alberta