Polymer [Pd(CHSOCHMe)], a precursor to remarkably stable Pd organometallics.

A polymer [Pd(CHSOCHMe)] is obtained by thermolysis of cis-[Pd(CHSOCHMe)(NCMe)] to release the MeCN ligands. The corresponding coordination sites are then occupied by weak Pd-O bonds, easier to break than the previous Pd-N bonds. This allows us to produce from the polymer cis complexes containing ligands weaker than NCMe, such as acetone or water. The complexes cis-[Pd(CHSOCHMe){OC(CD)}], cis-[Pd(CHSOCHMe)(OH)], and cis-[Pd(CHSOCHMe)(OH){OC(CD)}], and cyclic dimers [Pd(CHSOCHMe)(OH)] with bridging methylsulphone groups are formed. The Pd : PPh : OH 1 : 1 : 1 reaction of the polymer produces cis-[Pd(CHSOCHMe)(OH)(PPh)], which isomerizes to trans-[Pd(CHSOCHMe)(OH)(PPh)], with water O-coordinated to Pd and making hydrogen bonds to the two SO groups as seen in its X-ray structure. A similar role is played by RNH groups in the structures of trans-[Pd(CHSOCHMe)(NH)(PPh)] and the dimer μ-(NH)(trans-[Pd(CHSOCHMe)(PPh)]). In addition to these interesting intramolecular hydrogen bonding properties provided by the SO groups, the structural and H NMR data available suggest that the CHSOCHMe group is an interesting kind of strong alkyl σ donor, with high trans influence, and forms very stable Pd complexes extraordinarily resistant to reductive elimination and to hydrolysis by water at room temperature.