Structural conformation and optical and electrochemical properties of imidazolyl-substituted naphthalenediimide and its Hg^II, Cd ^II, and Cu^II halide complexes

A new end-core-end naphthalenediimide-based ligand N,Na'-bis(3-imidazol-1- yl-propyl)naphthalene diimide (3-imntd) was synthesized. Single crystals of the free ligand and its Hg^II, Cd^II, and Cu^II halide complexes were obtained. All the compounds were fully characterized by elemental analysis, IR spectroscopy, single-crystal XRD, and DFT studies. The XRD and DFT calculations revealed three different kinds of conformations for 3-imntd (cis, trans, and L). The variation in the ligand conformation and the resulting final structures of the coordination assemblies, M₂L ₂ metallacycle, 1D zigzag chain, or ML metallacycle, seem to be induced by the different geometric characters of the coordination tetrahedra around the metal centers. The optical and electrochemical properties of the compounds were also investigated.