Insights into the bonding between tributylphosphine chalcogenides and zinc(II)

We present a first-principles systematic study on the bonding and structure of the complexes between zinc(II) chloride and tributylphosphine chalcogenides, n-Bu 3 PE (E = O, S, Se). These investigations are carried out within the framework of the density functional theory with and without considering the dispersion corrections evaluated at the GD3 level. Inspection of the calculated binding energies, orbitals, charge transfers and natural bond orbital analysis shows the importance of the interplay between σ- and π-type bonding within P–E and E–Zn in the formation of these complexes. Calculations reveal that the P–E–Zn angle goes from 120° to 90° when going from O to Se. In the complexes, the P–E bonds resemble those in the isolated PE − diatomic anions, where an electron density excess is found on the chalcogen E whatever its nature. A bonding model for this type of organometallic complexes is proposed and discussed here for the first time.