Ligand-Unsupported Cuprophilicity in the Preparation of Dodecacopper(I) Complexes and Raman Studies.

Synthesis and characterization of two dodecacopper(I) extended metal atom chains (EMAC) assembled by two hexadentate bis(pyridylamido)amidinate-supported hexacopper(I) string complexes (monomers) via the ligand-unsupported cuprophilicity are described. In addition to short unsupported Cu-Cu contacts, two hexacopper fragments in these two dodecacopper EMACs show a bent conformation based on X-ray crystallography. Compared with their THF-bound hexacopper(I) monomers and protonated ligands, these ligand-unsupported cuprophilic interactions are shown to be weak by Raman spectroscopy. DFT calculations suggest the ligand-unsupported cuprophilicity originate from weak attractive orbital interactions, and the strength is estimated to be 2.4 kcal mol .