β-meso covalently linked novel dipalladium(II) bis-dipyrrin complex

Abstract

β-Meso covalently linked bis-dipyrrin ligand was synthesized by removing BF₂ unit from β-dipyrrinyl BODIPY under mild Lewis acid catalyzed conditions and the resulted bis-dipyrrin ligand was used to prepare the first example of dipalladium(II) bis- dipyrrin complex by treating it with Pd(acac) ₂ in CH₂Cl₂ at reflux temperature. The formation of dipalladium bis-dipyrrin complex was confirmed by HR-MS, 1D, 2D NMR spectroscopy and X-ray crystallography. The crystal structure revealed that both the Pd(II)-dipyrrin units are nonplanar and makes an angle of ∼59° with each other. The Pd(II) ions were slightly deviated from the dipyrrin plane and each Pd(II) ion was in square planar geometry co-ordinating to two nitrogen atoms of dipyrromethene unit and two oxygen atoms of acetylacetonate ligand. The preliminary studies indicated that dipalladium bis-dipyrrin complex can be used as efficient catalyst for Suzuki-Miyaura cross coupling reactions.