Synthesis, structural characterization and properties of some novel siloxane-based bis-Schiff base copper(II), nickel(II) and manganese(II) complexes

In this paper we describe the synthesis and characterization of three metal complexes, namely CuL(Id3c) , NiL(Id4c) and MnL(Id6c) , obtained from a Schiff base ligand containing a flexible tetramethyldisiloxane group. The molecular structures of the metal complexes are determined by X-ray single-crystal diffraction analysis, FT-IR and UV-vis spectroscopy and elemental analysis. The inability of the tetramethyldisiloxane units to be involved in H-bond formation hinders the structure packing. Centro-symmetrical dimers of NiL(Id4c) and MnL(Id6c) are formed through π-π stacking interactions between the aromatic rings or by weak C-H···O intermolecular contacts in CuL(Id3c) . The optical and fluorescence properties of the ligand and metal complexes are reported and discussed in relation to their structures.