Inverse sodium hydride:: A crystalline salt that contains H+ and Na-

A crystalline salt has been synthesized that contains H+ and Na- rather than the usual hydride oxidation states of H- and Na+. The key is irreversible encapsulation of H+ within the cage of 36adamanzane (Adz). The internal proton is kinetically inert to reduction by Na- in solution in NH3-MeNH2 mixtures. Synthesis of the sodide is accomplished by a metathesis reaction between Na and AdzH+X- in which X- is a sacrificial anion such as glycolate, isethionate, or nitrate. Reduction or deprotonation of the sacrificial anion forms insoluble byproducts and AdzH+Na- in solution. After solvent removal, the sodide is dissolved in dimethyl ether and transferred through a frit into a separate chamber for crystallization. The compound was characterized as the sodide by analysis, NMR spectra, and optical absorption spectroscopy. Copyright © 2002 American Chemical Society.