A new and mild method was developed for the chemoselective conversion of mono-, bis- and tris-aminosiloxanes into their corresponding mono-, bis- and tris-dithiocarbamates, using alkaline hydrides and carbon disulfide in THF. Enhanced scavenging capacity towards mercury ions was observed when these compounds were grafted on silica compared to amine-functionalized silicas or to commercial resins bearing dithiocarbamate moieties.