Room-Temperature Carbon–Sulfur Bond Activation by a Reactive (dippe)Pd Fragment

The reactivity of [Pd­(dippe)­(μ-H)]2 (1) and [(μ-dippe)­Pd]2 (2) (dippe = 1,2-bis­(diisopropylphosphino)­ethane)
toward C–S bonds in thiophene derivatives and thioethers was
investigated, which led to C–S bond activation products. The
thiapalladacycles derived from thiophenic substrates were fully characterized
by 1H, 31P, and 13C NMR spectroscopy,
elemental analysis, and X-ray diffraction. The stability of the C–S
insertion products was probed by performing competition experiments
which follow the thermodynamic stability order (dippe)­Pd­(κ2C,S-benzothiophene) (6) > (dippe)­Pd­(κ2C,S-dibenzothiophene) (8) > (dippe)­Pd­(κ2C,S-thiophene) (3). The reactivity of the thiapalladacycles with small molecules such
as H2, CO, and alkynes was investigated.