Analysis of fluorescence quenching of naphthalene by two mercury containing organometallic complexes

Two organometallic complexes, named [Hg(2-C6H4PPh2)2] (1) and [{Au(C6F5)}2{Hg(2-C6H4PPh2)2}] (2) have been studied as quenchers of the fluorescence of naphthalene. Positive deviations were observed in the Stern-Volmer (S-V) plots for both quenchers. The analyses of the data reveal the existence of transient components in the dynamic quenching. The diffusion coefficients of these complexes have been obtained by two different methods, through the Stokes-Einstein equation, and from 1H PGSE NMR experiments. With these values, and taking into account the experimental KT constants, the radii of the transient quenching spheres were obtained, which show unusually large values.