Reactions of zinc hydride and magnesium hydride with pyridine; synthesis and characterization of 1,4-dihydro-1-pyridylzinc and -magnesium complexes

Abstract

The synthesis and characterization of 1,4-dihydro-1-pyridylzinc and -magnesium complexes are described. Zinc hydride and magnesium hydride dissolve in and react with pyridine, and the reaction has been studied in detail in the case of zinc hydride. Evaporation of the solvent after 1–2 hours at 0°C yielded a product containing pyridine, a 1,4-dihydropyridyl moiety and zinc hydrogen bonds, and two alternative structures are proposed for this complex. When the reaction was carried on for a long period, a yellow precipitate began to separate after about 40 hours, and reaction was complete after 7 days. The yellow product was identified as the pyridine complex of bis(1,4-dihydro-1-pyridyl)zinc. The corresponding magnesium complex was obtained from the reaction between magnesium hydride and pyridine for 50 hours at room temperature.