Enhanced Raman scattering from liquid metal films formed from silver sols

The production of mobile silver films at the interface between an aqueous silver sol and a solution of a transition-metal complex in an organic solvent is reported. The films exhibit very similar physical properties to those described in a recent report but are produced by a simpler method of shaking together the sol and a solution of metal complex in a nonaqueous solvent. The phenomenon has been observed for several complexes of Cu{sup I}, Fe{sup II}, and Fe{sup III} and affords a novel method of investigating Raman scattering of water-insoluble complexes near a metal surface. In a number of the examples investigated, significant enhancement of scattering is observed similar to the surface-enhanced (resonance) Raman scattering from silver sols.