Synthesis and characterization of some heteroleptic copper(II) complexes based on meso-substituted dipyrrins

Abstract

The syntheses and characterizations of meso-substituted dipyrrins, 5-(4-imidazol-1-yl-phenyl)-dipyrromethene (4-impdpm), 5-(4-nitro-imidazol-1-yl-phenyl)-dipyrromethene, (4-nimpdpm), 5-(4-benzimidazol-1-yl-phenyl)-dipyrromethene (4-bimp-dpm) and heteroleptic complexes [Cu₃(4-impdpm)₂(hfacac)₄] 1, [Cu(4-nimpdpm)(acac)] 2, [Cu(4-nimpdpm)(hfacac)] 3, [{Cu(4-bimpdpm)(acac)}_n] 4 and [{Cu(4-bimpdpm)-(hfacac)}_n] 5, imparting acetylacetonato (acac) and hexafluoroacetylacetonato (hfacac) groups as co-ligand have been described. The dipyrrins and complexes 1-5 have been characterized by elemental analyses and spectral (IR ESI-MS, NMR, electronic absorption and emission) studies. Crystal structures of 1, 3 and 4 have been authenticated by X-ray single crystal analyses. The reaction between 4-impdpm and Cu(hfacac)2 gave a trimetallic complex, under analogous conditions 4-nimpdpm and 4-bimpdpm reacted with Cu(acac)₂ and Cu(hfacac)₂·2H₂O to afford mononuclear (2, 3) and 1D polymeric (4, 5) complexes.