Synthesis, structure, photophysical and catalytic properties of CuI–Iodide complexes of di-imine ligands

• Synthesis and characterization of two copper(I) iodide complexes of two different di-imine ligand.
• The bidentate di-imine ligand (L1) forms monomeric CuI complex (1).
• The bis-bidentate di-imine ligand (L2) favours the formation of dimeric CuI complex (2).
• Theoretical analysis shows that HOMO is focused on the Cu and iodides while LUMO is focused on di-imine ligands.
• The complexes 1 and 2 worked as effective catalyst for synthesis of 2-substituted benzoxazoles.

Two new multifunctional CuII based complexes [CuI(L1)] (1) and [Cu2(μ-I)2(L2)] (2) with bidentate N–N donor ligands L1 and imino-pyridyl ligand L2 have been synthesized and characterized by elemental analysis, IR, UV–Vis, NMR and single crystal X-ray crystallography. The bidentate di-imine ligand (L1) forms monomeric CuI complex (1) whereas the bis-bidentate di-imine ligand (L2) favours the formation of dimeric CuI complex (2) in association with two bridging iodides. Structural analysis reveals that in complex 1 each monomeric units are connected by π⋯π and C–H⋯π interactions to form 3D supramolecular structure whereas in complex 2 each molecules are connected by only π⋯π interactions to form 3D supramolecular structure. The photoluminescence properties of the complexes have been studied at room temperature. Theoretical analysis shows that HOMO is focused on the Cu and iodides while LUMO is focused on di-imine ligands and the luminescence behaviour arises due to metal to ligand charge transfer (MLCT) and halide to ligand charge transfer (XLCT). The complexes 1 and 2 are effective catalysts for the synthesis of 2-substituted benzoxazoles.

Single crystal structures and catalytic activity of two CuII based complexes [CuI(L1)] (1) and [Cu2(μ-I)2(L2)] (2) with bidentate N–N donor ligands L1 and imino-pyridyl ligand L2 have been reported. Theoretical analysis shows that HOMO is focused on the Cu and iodides while LUMO is focused on di-imine ligands and the luminescence behaviour arises due to metal to ligand charge transfer (MLCT) and halide to ligand charge transfer (XLCT).Figure optionsDownload as PowerPoint slide