Syntheses and conversions of dinuclear cadmium(II) compounds containing N2O/N2O2 donor tridentate/tetradentate asymmetrical Schiff base ligands

Through different synthetic strategies, four dinuclear cadmium(II) complexes containing N2O/N2O2 donor tridentate/tetradentate asymmetrical Schiff base ligands have been synthesized and characterized. The two complexes [Cd(L-1)(mu(2)-Cl)(CH3OH)](2) (1) and [Cd(L-2)Cl](2)center dot CH3OH (2) are constructed, respectively, from self-assembly of a Cd2+ ion with two asymmetrical Schiff base ligands, namely 2-((2-(dimethylamino) ethylimino) methyl) phenol (HL1) and 2-((2-(dimethylamino) ethylimino) methyl)-6-methoxyphenol (HL2). However, via single-crystal to single-crystal structural transformations driven by temperature, the other two corresponding compounds [Cd(L-1)Cl](2) (1a) (1 -> 1a) and [Cd(L-2)Cl](2) (2a) (2 -> 2a), with N2O2Cl and N2O3Cl donors, respectively, can be obtained. Obviously, the synthetic strategies presented in the text provide very effective methods for constructing the dinuclear Cd-II compounds with N2O/N2O2 donor tridentate/tetradentate asymmetrical Schiff base ligands. Meanwhile, the strong fluorescence emission of 1 and 2 makes them potentially useful photoactive materials.