Theoretical study on interactions of fluorinated organomercurials with arene and gold fragments

Abstract

The electronic structure and spectroscopic properties of [Hg(C₆F₅)₂]₂–{L}, [Hg₃(o-C₆F₄)₃]₂·{L} (L = naphthalene, biphenyl, fluorene) and [Hg₃(o-C₆F₄)₃]{Au₃(μ-C(OEt)NC₆H₄CH₃)₃}_n (n = 1, 2) adducts were studied at the HF, MP2, SCS-MP2, DFT and DFT-D3 levels. The intermolecular interactions among the fragments were analyzed using the levels of calculations proposed. The energy decomposition analysis at the TPSS-D3 level was used to define the dominant components of the interaction. The van der Waals interactions between mercury and arene (Hg–arene) were found to be the main short-range stability contribution in the [Hg(C₆F₅)₂]₂–{L} and [Hg₃(o-C₆F₄)₃]₂·{L} complexes. At the MP2, SCS-MP2 and DFT-D3 levels, equilibrium Hg–C distances are between 360 and 310 pm. The pair-wise energies were found to be between 18.0 and 6.0 kJ mol⁻¹. In the [Hg₃(o-C₆F₄)₃]{Au₃(μ-C(OEt)NC₆H₄CH₃)₃}_n (n = 1, 2) complexes the metallophilic intermolecular interaction is Hg–Au. Pair-wise energies of 85.7, 39.4, 78.1 and 57.9 kJ mol⁻¹ were found at the MP2, SCS-MP2, TPSS-D3 and PBE-D3 levels using the [Hg₃(o-C₆F₄)₃]{Au₃(μ-C(OEt)NC₆H₄CH₃)₃} model. The same trend is maintained for the [Hg₃(o-C₆F₄)₃]{Au₃(μ-C(OEt)NC₆H₄CH₃)₃}₂ model: 73.4, 29.3, 70.6 and 61.3 kJ mol⁻¹ by MP2, SCS-MP2, TPSS-D3 and PBE-D3, respectively. The absorption spectra of these complexes were calculated using the single excitation time-dependent method at the TPSS-D3 level to validate the models against the experimental data.