Adsorption of hydrogen on the stoichiometric electron donor-acceptor complexes of anthracene with sodium

Abstract

Hydrogen adsorption on stoichiometric EDA complexes of anthracene (An) with sodium, An^–Na⁺ and An^––2Na⁺, were studied by means of electronic absorption spectroscopy, e.s.r. and n.m.r. techniques, in addition to volumetric adsorption measurements. When hydrogen was absorbed on films of these complexes a new band was observed in the electronic absorption spectrum of anthracenium anion. The e.s.r. and n.m.r. techniques indicated that hydrogen molecule is heterolytically dissociated into H⁺ and H^– over the An^––2Na⁺ complex to from AnH^–Na⁺NaH. On the other hand, over the An^–Na⁺ complex, two reactions proceed simultaneously; (i) one hydrogen molecule is homolytically dissociated into two hydrogen atoms over the two An^–Na⁺ to from 2AnH^– and (ii) AnH^–Na⁺NaH and An are formed.