The title cluster (Pd-3(2+)) exhibits a pronounced affinity for Br- ions to form the very stable Pd-3(Br)(+) adduct. Upon a 2-electron reduction, a dissociative process occurs generating Pd-3(0) and eliminating Br- according to an ECE mechanism (electrochemical, chemical, electrochemical). At a lower temperature (i.e. -20 degreesC), both ECE and EEC processes operate. This cluster also activates the C-Br bond, and this work deals with the reactivity of Pd-3(2+) with 2,3,4-tri-O-acetyl-5-thioxylopyranosyl bromide (Xyl-Br), both alpha- and beta-isomers. The observed inorganic product is Pd-3(Br)(+) again, and it is formed according to an associative mechanism involving Pd3'+".Xyl-Br host-guest assemblies. In an attempt to render the C-Br bond activation catalytic, these species are investigated under reduction conditions at two potentials (-0.9 and -1.25 V vs SCE). In the former case, the major product is Xyl-H, issued from a radical intermediate Xyl(.) abstracting an H atom from the solvent. Evidence for Xyl(.) is provided by the trapping with TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) and DMPO (5,5'-dimethylpyrroline-N-oxyde). In the second case, only one product is observed, 3,4-di-O-acetyl-5-thioxylal, which is issued from the Xyl- intermediate anion.