(P-Bis(pentafluorophenyl) substituted) PCP-pincer Ru(II) complexes: A theoretical study of the molecular structure and electronic properties |
| |
| Authors: | Marcella Gagliardo Gerard van Klink |
| |
| Institution: | a Debye Institute, Organic Chemistry and Catalysis, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
b Debye Institute, Theoretical Chemistry Group,2Affiliated to Organic Chemistry and Catalysis.2 Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands |
| |
| Abstract: | The differences between the molecular structures of the PCP-pincer complex RuCl{C6H3(CH2P(C6H5)2)2-2,6}(PPh3)] (RuCl(PCPH)(PPh3)], 1) and its tetrakis-pentafluorophenyl substituted analogue RuCl{C6H3(CH2P(C6F5)2)2-2,6}(PPh3)] (RuCl(PCPF20)(PPh3)], 2) have been rationalised by performing calculations on the cations Ru(PCPH)(PPh3)]+ (1cat) and Ru(PCPF20)(PPh3)]+ (2cat). The molecular interactions between the chloride ligand and the axial rings, as found in 1 and 2, respectively, have been studied computationally in the model systems (C6X5PH2)2Cl−] (X = H, F). The calculations on 2cat show that in 2 it is most likely the attractive electrostatic interaction between the chloride ligand and the fluorinated phenyl rings that forces the Cipso atom to occupy an axial position rather than an equatorial one in the observed (X-ray of 2) square pyramidal arrangement. In 1, however, repulsive steric hindrance forces the PPh3 ligand to take the apical position. The applicability of the TD-DFT method for the calculation of the electronic spectra of the PCP-pincer compounds 1 and 2 has been tested. The results indicate that the excitation energies calculated for both complexes are in a reasonable agreement with the experimental absorption maxima. However, for 1, all the calculated transition energies are underestimated. |
| |
| Keywords: | DFT and ab initio calculations Electrostatic interactions PCP pincer ligands Ruthenium(II) |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
