J Mol Graph Model 2019 Jul 11;90:226-234. Epub 2019 May 11.
Department of Physics, Nanyang Normal University, Nanyang, 473061, China; Department of Physics and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, NV, 89154, United States.
The ground state structures of neutral and anionic Ln(COT) (Ln = Ce, Nd, Eu, Ho and Yb; n, m = 1, 2) complexes have been identified by density functional theory. Ln(COT) and Ln(COT) complexes are found to possess sandwich ground state structures in which Ln atoms and COT molecules are alternately stacked except for NdCOT. Our calculated AEA and VDE values show good agreement with the available experimental values, which validates that our obtained ground state structures are credible. Based on the frontier molecular orbitals, we find that the bond formation between the 4f electrons of Ln atoms and the π clouds of COT molecules is weak. Then, the bond strength within these complexes is further analyzed based on the topological analysis of electron density at bond critical point. By analyzing Hirshfeld charge, we find Ln(COT) are charge-transfer complexes with weak bonding feature.