Cyclopalladated hydrazones complexed to pyridinyl ligands

Abstract

2-Benzoylpyridine and 2-acetylpyridine N-methyl- N-phenylhydrazones ( HL 1 and HL 2) in cyclopalladation reactions with Pd 3(OAc) 6 behave as N(py)N(im)C tridentate ligands and form the neutral mononuclear complexes [Pd( k 3-N,N,C–L 1,2)( k 1-OAc)] ( 1 and 2). The labile OAc ligand can be replaced by pyridine (py) and, in the presence of NH 4PF 6, a compound of the general formula [Pd( k 3-N,N,C-L 1,2)(py)]PF 6 ( 3 and 4) can be obtained. Reacting 1 or 2 with the poly(4-vinylpyridine) polymer (PVP, M ¯ w = 160 000 ) adducts of the general formula x[Pd( k 3-N,N,C-L 1,2)(PF 6)] · y[PVP] gives ( 5a– c and 6a– c, a– c: x/ y = 80/20, 50/50, 25/75 w/w) containing the laterally appended cyclopalladated “Pd( k 3-N,N,C-L 1,2)” fragments. These metallorganic polymers show high glass transition temperatures, high thermal stability and good solubility, and are optimal for obtaining transparent thin films by the spin coating method.