Synthesis, structural, vibrational and DFT investigation of new binuclear molecular Pd–Cu and Cu–Cu complexes formed by Schiff base and hexafluoroacetylacetonate building blocks

Abstract

In this work, the first binuclear molecular noble metal-contained complex from the Schiff base (SB) and β-diketonate building blocks, viz. [Pd(acacen)Cu(hfac)2], has been synthesized and investigated in comparison with the homometallic binuclear analog [Cu(acacen)Cu(hfac)2]. The detailed comparative characterization of the structure of these new compounds as well as their molecular SB components [M(acacen)] was performed using crystallography, vibrational spectroscopy and DFT calculations. Experimental IR bands have been assigned based on DFT calculations. The Hirshfeld surface analysis was used as a tool for the better insight into intermolecular contacts. It was shown that despite both bimetallic complexes had similar molecular structure and packing style, the nature of the closest intermolecular contacts in [M(acacen)Cu(hfac)2] differed considerably. A topological analysis of the electron density distribution in [M(acacen)] and [M(acacen)Cu(hfac)2] complexes was carried out and the most probable paths of bond cleavage during decomposition of the compounds were revealed. The binding energies of the molecular components in binuclear complexes were also calculated.