Nuclear-Spin Isotope Effects in Organotin Compounds
Nuclear-spin isotope effects that result in Chemically Induced Dynamic Nuclear Polarization (CIDNP) were theorized to be present in organotin compounds. An unknown substrate (1-phenyl-3-(tri-n-butylstannyl)-1-propanone) was designed so that it would exhibit nuclear-spin isotope effects resulting in the selective enrichment of the starting material in the tin nuclei of spin I = 1⁄2 when subjected to a photolytic reaction. Three major synthetic schemes were explored, utilizing a phenyl Grignard along with an organotin nitrile, organotin ester, or ␣␣␣␣␣␣␣␣␣␣ ␣␣␣␣␣␣␣␣␣␣␣ ␣␣␣␣␣␣ ␣ ␣␣␣␣ ␣␣␣␣␣␣␣␣␣␣ ␣␣␣␣␣␣␣␣␣␣␣␣␣ ␣␣␣␣␣␣␣␣␣␣␣ ␣␣␣␣␣␣ ␣␣␣␣␣␣␣␣␣ ␣␣␣␣␣␣␣␣ ␣␣ ␣␣␣␣ sodium bisulfite were also explored to purify the material before photolysis and to recover the starting material after photolysis. The synthetic products were characterized by both one- and two-dimensional NMR experiments, as well as IR spectroscopy. It was found that the most effective synthetic scheme involved the organotin ester, and that neither purification process was sufficient for the desired purpose.