Synthesis, Experimental and Theoretical Characterization of (μ4-oxo)hexakis(μ2-chloro)-tetrakis[1-(allyl)-1H-imidazole]tetracopper(II)

: A new [Cu 4 OCl 6 L 4 ] cluster [L = 1 -(allyl)-1 H -imidazole] has been isolated and its crystal structure and spectroscopic properties determined. The compound crystallizes as a yellow solid in the monoclinic system, space group P 2 1 , with cell constants a = 10.6937(7) Å, b = 13.1004(7) Å, c = 13.2452(9) Å, β = 93.537(6)°, and two formula units per cell. The title tetranuclear complex has a central µ 4 - oxide ion surrounded tetrahedrally by four Cu II atoms. Each Cu atom is connected to three others via bridging Cl atoms. The fifth coordination position, located on the central Cu─O axis on the outside of the cluster, is occupied by an N atom of the monodentate imidazole ligand. The resulting coordi nation geometry of the metal ion is a slightly distorted trigonal bipyramid with the O and N atoms in the axial positions. Th e molecular structure and spectroscopic data were obtained using density functional theory (DFT/HSEH1PBE) method with the cc - pVDZ basis set for C, H, N, O and Cl atoms, and the LANL2DZ basis set for the Cu atoms, and compared with the experimental data. Consequently, the exp erimental data well coherences with the theoretical ones.