A theoretical study of structure, bonding and property of platinum(II)-8-hydroxyquinolines complexes with carbene and heavier homologues

Abstract

<p>In this work, a theoretical study for platinum(II)-8-hydroxyquinolines-tetrylene complexes [{PtCl-C<sub>9</sub>H<sub>6</sub>NO}-NHE<sub>Ph</sub>] (<strong>Pt-EPh</strong>)<strong> </strong>are investigated for the first time using density functional theory (DFT). Quantum chemical calculations using DFT and charge methods at the BP86 level with basic sets SVP, TZVPP have been carried out to get insight into the structures and property for <strong>Pt-EPh</strong>. The optimization of equilibrium geometries of the ligands<strong> EPh</strong> in <strong>Pt-EPh</strong> are bonded in distorted end-on way to <strong>Pt</strong> fragment with the bending angle, a, slightly decreases from carbene <strong>Pt-CPh</strong> to germylene <strong>Pt-GePh</strong>. Quantum chemical parameters such as <em>E</em><sub>HOMO</sub>, <em>E</em><sub>LUMO</sub>, the energy gap (<em>E</em><sub>LUMO </sub>– <em>E</em><sub>HOMO</sub>), electronegativity (χ), global hardness (η), and global softness (<em>S</em>) in the neutral molecules have been calculated and discussed. Bond dissociation energies (BDEs), D<sub>e </sub>(kcal.mol<sup>-1</sup>), decrease from the slighter to the heavier homologues. The hybridization of atoms E have large p characters while the hybridization of atom Pt has greater d character which lead to the Pt-E bond possesses not only NHE<sub>Ph</sub>→{ PtCl-C<sub>9</sub>H<sub>6</sub>NO} strong σ-donation but also a significant contribution π-donation NHE<sub>Ph</sub>→{PtCl-C<sub>9</sub>H<sub>6</sub>NO} and a weak π-backdonation metal-ligand NHE<sub>Ph</sub>←{PtCl-C<sub>9</sub>H<sub>6</sub>NO} in complexes <strong>Pt-Eph </strong>was also considered.</p>