Reactivity of metallic copper with acidic organic compounds in the presence of molecular oxygen. Crystal structure of [{Cu(NCO)(py)2}2]·H2O

Abstract

The reactivity of metallic copper with organic compounds containing acidic hydrogen atoms such as MeOH, PhOH, PhCO₂H, and MeNO₂in the presence of O₂ and pyridine has been studied. The reaction with MeNO₂ is particularly interesting as it gives cyanide, isocyanate, and nitrite compounds, depending on the reaction conditions. The crystal structure of a minor product, the previously unknown complex [{Cu(NCO)(py)₂}₂]·H₂O, has been determined by X-ray diffraction methods. It consists of a copper dimer, where each metal is in a tetrahedral arrangement determined by two N atoms from pyridine ligands and two N atoms from two isocyanate ligands acting as asymmetric bridges; angles at the bridging N atoms are very acute, 68.6(5) and 71.8(6)°, and the Cu ⋯ Cu distance is very short, 2.396(3)Å.