On adsorption of some electron-acceptor molecules on the solid films of all-trans-beta-carotene, beta-apo-8'-carotenal, astacene and methylbixin a new absorption band appears on the longer-wavelength side of the spectrum in addition to the original bands. The position of this new band is dependent on the electron affinity (EA) of the acceptor molecules, and the intensity of this band increases with the amount of adsorbed acceptor molecules. A linear relationship between the vmax. of the new band and EA was observed. The value of the ionization potential of the polyenes estimated from such linear relationship agrees satisfactorily with the value obtained by other methods. It has been concluded that the polyenes behave as electron donor and first form molecular charge-transfer complexes (of type [polyene . I2] with iodine) with electron acceptors, these finally dissociating to yield ionic complexes (of type [polyene . I+] with iodine).

The ability of vitamin A acetate to form charge-transfer (CT)-complexes in the solid state with electron acceptors has been exploited for the direct conversion if chemical energy into electrical energy. The electrochemical cell devised for this purpose has the configuration zinc/CT complex/Pt or graphite. An open-circuit voltage of 1.08 V and short-circuit current densities of up to 5 mA/cm2 were found at room temperature. The current-voltage and discharge characteristics gave a maximum power density of 4.0 W/kg and a useful energy density of 17 W·h/kg, respectively. The battery was found to be useful in operating various low-power-consuming electronic circuits.

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The validity of the compensation rule is studied for nucleic acid bases, adenine, cytosine, and uracil complexes with acriflavine dye. The value of the semiconduction activation energy of a complex varies with dye concentration. It is shown that at low dye concentration, these semiconducting complexes follow the three parameter equation σ(T)=σ′0exp(E⁄2kT0)exp(−E⁄2kT), where σ′0 and T0 are constant for a particular base, other notations have their usual meaning. Consistent values for σ′0 and T0 have been obtained by using various methods of evaluation. These results suggest that compensation effect has a physical origin.