Palladium(II) acetate (I) and two new complexes of the ligand alpha,alpha,alpha',alpha'-tetramethyl-1,3-benze-nedipropionate (esp(2-)), C-s-Pd-3(esp)(3) (C-s-2) and C3h-Pd3(esp)(3) (C-3h-2), are studied in the solid state and in solution. Variable-temperature NMR and DFT studies of C-s-2 reveal an unusual shielding region above the Pd atoms. The compounds show a surprising quasi-reversible reduction between -880 and -1200 mV versus Fc/Fc(+), and the Pd-3(esp)(3) complexes may be cleanly reduced electrochemically. EPR spectra of reduced samples show pseudo-axial signals with Pd-105 hyperfine coupling, consistent with unprecedented, isostructural Pd-3(5+) species with a valence-trapped Pd-II-(PdII-PdI) electronic structure.