Electronic Structure of 1,5-Cyclooctadiene-copper(I)-hexafluoroacetylacetonate

The valence electronic structure of the compound 1,5-cyclooctadiene-copper(I)-hexafluoroacetylacetonate [(1,5-COD)Cu(hfac)], a prospective precursor for creation of thin copper films for microelectronics, has been investigated by ultraviolet photoelectron (He I) and X-ray emission spectroscopy. Electronic interactions of the 1,5-COD ligand with the copper atom were revealed by comparing spectra of the complex and of free 1,5-COD. C Kα spectra indicated a significant decrease of π electron density in the double bonds of 1,5-COD with the coordination of this molecule to the copper atom. The spectral changes and features were interpreted using the results of density functional calculation on the molecules. The detailed analysis of the highest occupied molecular orbitals of (1,5-COD)Cu(hfac) was carried out to explain the relatively low values of first ionization potential and decomposition temperature for the complex.