Mononuclear versus dinuclear palladacycles derived from 1,3-bis(N,N-dimethylaminomethyl)benzene: Structures and catalytic activity

Mononuclear and dinuclear palladacycles derived from 1,3-bis(N,N-dimethylaminomethyl)benzenes, [{Pd(Cl)}2,6-(Me2NCH2)2C6H3] (1) and [1-{Pd(H2O)(Py)}-5-{Pd(OTf)(Py)-2,4-(Me2NCH2)2C6H2]-(OTf) (2), were synthesized and their structures were fully characterized. Complex 1 is a pincer complex with η3-mer NCN phenyl backbone, complex 2 is a bispalladium(II) complex with 1,2- and 4,5- two C,N-ortho phenyl backbone. Whereas the pincer complex 1 acted as a poor catalyst on methanolysis of fenitrothion, complex 2 demonstrated high catalytic activity in the same reactions, but there is no synergetic effect between two palladium ions. The results clearly indicate that a dissociable co-ligand in the palladacycle compounds significantly promotes the catalytic methanolysis.