A new tetranuclear copper(I) cluster of 1,3-bis(4-bromophenyl)triazene ligand: Synthesis, characterization, structural and computational studies

Abstract

The synthesis, characterization, crystal structure and computational studies of a new tetranuclear Cu(I)–triazene cluster complex is reported. The tetranuclear cluster complex, Cu4L4, is obtained by the reaction of 1,3-bis(4-bromophenyl)triazene (HL) and [Cu(CH3CN)4]PF6 in THF solvent in the presence of triethylamine. The four copper atoms are located at the corner of a rhomboid with the triazenido ligands bridged above and below the near plane of the four Cu(I) atoms in which the copper atoms are arranged in a square [CuCuCu=88.171(8)°] geometry. DFT/TDDFT calculations were performed to investigate the electronic and optical properties of the complex in solution. TDDFT calculations in DMSO using the polarizable continuum model (CPCM) show two absorption maxima at 371 and 282nm which assigned to the mixing of MLCT and π→π∗ characters and reproduces the main features of the experimental spectrum. A detailed investigation of the crystal packing and noncovalent CH⋯Br and π⋯π interactions is presented by means of Hirshfeld surface analysis, showing high contribution of the non-classic CH⋯Br interaction in the crystal packing. The nature of the noncovalent interactions is also studied by nciplot program.