Noble Gas Binding Ability of an Au(I) Cation Stabilized by a Frustrated Lewis Pair: A DFT Study.

Manas Ghara,Pratim Kumar Chattaraj

doi:10.3389/fchem.2020.00616

Manas Ghara, Pratim Kumar Chattaraj

Open Access

https://doi.org/10.3389/fchem.2020.00616

Copy DOI

Abstract

The noble gas (Ng) binding ability of a monocationic [(FLP)Au]+ species has been investigated by a computational study. Here, the monocationic [(FLP)Au]+ species is formed by coordination of Au(I) cation with the phosphorous (Lewis base) and the boron (Lewis acid) centers of a frustrated Lewis pair (FLP). The bonds involving Au and P, and Au and B atoms in [(FLP)Au]+ are partially covalent in nature as revealed by Wiberg bond index (WBI) values, electron density analysis and energy decomposition analysis (EDA). The zero point energy corrected bond dissociation energy (D0), enthalpy and free energy changes are computed for the dissociation of Au-Ng bonds to assess the Ng binding ability of [(FLP)Au]+ species. The D0 ranges from 6.0 to 13.3 kcal/mol, which increases from Ar to Rn. Moreover, the dissociation of Au-Ng bonds is endothermic as well as endergonic for Ng = Kr-Rn, whereas the same for Ng = Ar is endothermic but exergonic at room temperature. The partial covalent character of the bonds between Au and Ng atoms is demonstrated by their WBI values and electron density analysis. The Ng atoms get slight positive charges of 0.11–0.23 |e|, which indicates some amount of charge transfer takes place from it. EDA demonstrates that electrostatic and orbital interactions have equal contributions to stabilize the Ng-Au bonds in the [(FLP)AuNg]+ complex.

Highlights

The noble gas (Ng) elements (He, Ne, Ar, Kr, Xe, and Rn) were have been supposed to be non-reactive in forming chemical bonds with other elements in the periodic table
Effectiveness of the MO6-2X-D3 in certain cases has been shown earlier albeit with the presence of some amount of medium range interaction in MO6-2X (Burns et al, 2011) Vibrational frequencies are calculated to confirm whether the stationary points belong to a minimum on the potential energy surface (PES) or a higher order saddle point
The computed Au-P and Au-B bond distances are 2.29 and 2.38 Å respectively, whereas the experimental bond distances of these bonds are 2.27 and 2.35 Å respectively when a chloride ion is attached to the Au center of the complex (Ueno et al, 2019)

Summary

INTRODUCTION

The noble gas (Ng) elements (He, Ne, Ar, Kr, Xe, and Rn) were have been supposed to be non-reactive in forming chemical bonds with other elements in the periodic table. Effectiveness of the MO6-2X-D3 in certain cases has been shown earlier albeit with the presence of some amount of medium range interaction in MO6-2X (Burns et al, 2011) Vibrational frequencies are calculated to confirm whether the stationary points belong to a minimum on the potential energy surface (PES) or a higher order saddle point. This techniques provides the zero point energy (ZPE) and the thermodynamic corrections at 298.15 K temperature. The deformation in charge density ρk(r), with orbital pairs ρk(r) and ψ−k(r) get mixed up provides the amount and the direction of the charge flow (Equation 3), and the related energy term Eorb gives the amount of stabilization in orbital energy (Equation 4)

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT