Photochromism of silver(I) and mercury(II) dithizonates : Effect of excess of free ligand on the return to ground state and effect of silver(I) dithizonate on the return of mercury(II) dithizonate

The energy of photons producing highest yield in the photochromic excitation of both silver(I) and mercury(II) dithizonate is shown to be centered around 520 nm. The effect of silver(I) dithizonate on the return of the excited form of mercury(II) dithizonate to the ground state is described. The accelerating effect of the silver complex is interpreted by an empirical kinetic model that takes into consideration the concurrent excitation and relaxation of both complexes. As observed in the photochromism of mercury(II) dithizonate, the presence of excess of ligand proportionally hastens the relaxation of silver(I) dithizonate to the ground state.