The mechanism of the reaction between molecular hydrogen and the electron donor-acceptor complexes (1 : 1 and 1 : 2) of various aromatic hydrocarbons with sodium

The mechanism of the reaction between molecular hydrogen and the electron donor-acceptor complexes (A(-)Na(+) and A=2Na(+)) of various aromatic hydrocarbons (A) with sodium were studied kinetically and spectroscopically. The relative activity of each electron donor-acceptor (EDA) complex for the hydrogen uptake was associated with its electronic properties, especially with the reduction potential of its anion. It was found that the hydrogen molecule reacts more readily with stronger electron-donating EDA complexes, whose anions have higher reduction potentials. It was also suggested that, on the hydrogen adsorption over the A(-)Na(+) and A=2Na(+) films (or in their solutions), the corresponding monohydroanion complexes (AH-Na+) and NaH were produced as follows: 2A-Na+ + H-2 = AH(-)Na(+)NaH + A A(-)2Na(+) + H-2 = AH(-)Na(+) + NaH The behaviour of AH(-)Na(+) was closely correlated with the localization energies of electrons in the anions of the aromatic hydrocarbons.