Synthesis and characterization of new oxazoline-based palladacycles with bridging or terminal imidate ligands. Crystal structures of [{Pd(μ-dibromomaleimidate)(Phox)} 2], [Pd(dibromomaleimidate)(Phox)(PPh 3)] and [Pd(glutarimidate)(Phox)(PPh 3)] (Phox = 2-(2-oxazolinyl)phenyl))

Abstract

The dinuclear hydroxo complex [{Pd(μ-OH)(Phox)} 2] ( I) (Phox = 2-(2-oxazolinyl)phenyl) reacts in a 1:2 molar ratio with several imidate ligands to yield new cyclometallated palladium complexes [{Pd(μ-NCO)(Phox)} 2] containing asymmetric imidate –NCO– bridging units. [–NCO– = succinimidate (succ) ( 1), phtalimidate (phtal) ( 2), maleimidate (mal) ( 3), 2,3-dibromomaleimidate (2,3-diBrmal) ( 4) and glutarimidate (glut) ( 5)]. The reaction of these complexes with tertiary phosphines provides novel mononuclear N-bonded imidate derivatives of the general formula [Pd(imidate)(Phox)(PR 3)] [R = Ph ( a), 4-F–C 6H 4 ( b) or CH 2CH 2CN ( c)]. The new complexes were characterized by partial elemental analyses and spectroscopic methods (IR, FAB, 1H, 13C and 31P). The single-crystal structures of compounds 4, 4a and 5a have been established.