We are developing a relatively new technique, nuclear quadrupole double resonance, NQDR for the study of diamagnetic solid samples containing quadrupolar nuclei. Among the important elements containing such nuclei are nitrogen (14N), oxygen (170), magnesium (25Mg), zinc (67Zn), molybdenum (95Mo,97Mo), and many others. We are especially interested in using the biologically important molecules such as amino acids, peptides, nitrogen-containing heterocycles, nucleotides, and so forth. We are further extending these studies to complexes in which some of the nitrogen centers are bonded to metal ions. Complexes of imidazole and histidine, and peptides containing histidine, are under investigation. Complexes containing 67Zn will be prepared and their NODR spectra determined. When a sufficient body of such data are available (there are none now), it will be possible to employ the NQDR data to learn about the details of the environment about the metal ion. The sensitivity of the technique is potentially very high. Provided that certain spin-lattice relaxation problems can be overcome, it should be possble to detect one Zn2 ion or one Mg2 ion in a molecular weight of 50,000 and more, in a sample of perhaps 100mg. We intend to develop new instrumentation in attempts to reach these goals.
NIH ExPorter
NIH ExPorter