Unsymmetrical dendrimers with tridentate pyridylthioether coordination sites as repeating units: useful precursor for the synthesis of palladium-containing metallodendrimers

Unsymmetrical pyridylthioether monomers derived from 2,6-bis(hydroxymethyl)-3-hydroxypyridine hydrochloride have been used to synthesize dendritic structures by a convergent route. The coupling of the monomers has been achieved by the Mitsunobu reaction. The presence of repeating SNS pincer units makes these molecules precursors of metallodendrimers. The complexation of each binding site with palladium has been achieved upon reaction either with Pd2(DBA)3CHCl3 in the presence of fumaronitrile or PdCl2(CH3CN)2.