A comparative study between post-Hartree–Fock methods and density functional theory in closed-shell aurophilic attraction

Closed-shell d10-d10 mechanochromic [AuPh(CNPh)]n complex: quantum chemistry electronic and optical properties

The electronic structure, spectroscopic properties, and solid state chemistry of monomer and dimers of [AuPh(CNPh)] complex were studied at post-Hartree-Fock (MP2, SCS-MP2, and CC2) and density functional theory levels. The absorption spectra of these complexes were calculated using single excitation time-dependent (TD) methods at DFT, CC2, and SCS-CC2 levels. The influences of the bulk are accounted for at the PBE-D3 level, incorporating dispersion effects. The calculated values agree with the experimental range, where absorption and emission energies reproduce experimental trends with large Stokes shifts. The aurophilic interaction is identified as a key factor influencing the spectroscopic and structural properties of these complexes. The intermetallic interactions were found as the main factor responsible for MMCT electronic transitions in the models studied.

Is there a Covalent Au(I)-Au(I) Bond in the trans-(AuX)2 (X = F, Cl, Br, I) Structure? A Post-Hartree-Fock and Density Functional Theory Study

We present an exhaustive exploration of the driving forces dominating the interaction between gold atoms in the trans-(AuX)2, where X is a halogen ligand. This work provides insights into the nature of the gold-gold contact in the trans-(AuX)2. The geometries and energies were calculated at the MP2, CCSD(T), and DFT-D3(BJ) (B3LYP, PBE, and TPSS) levels of theory. The results show a short Au-Au distance, typical of a covalent bond, but with a weak interaction energy associated with noncovalent interactions. It is established that the physical contributions from polarization and the electronic correlation forces are the most relevant at the post-Hartree-Fock level of theory. Also, the electrostatic term is attractive but with low contribution. Finally, the Wiberg indices and NBO analysis exposed a small covalent character between the gold atoms, revealing that this contribution is insufficient to explain the stability of the dimers. It is concluded that a sum of contributions makes it possible to establish an attraction between the gold atoms in the dimers studied beyond a classical aurophilic interaction.

Closed-shell d10–d10 in [AuCl(CNR)]n and [AuCl(CO)]n (n = 1, 2; R = –H, –CH3, –Cy) complexes: quantum chemistry study of their electronic and optical properties

The [AuCl(CNR)] and [AuCl(CO)] (R = –H, –CH3, –Cy) complexes were modeled and their electronic and optical properties described.

Thermal Growth of Au-Fe Heterometallic Carbonyl Clusters Containing N-Heterocyclic Carbene and Phosphine Ligands

The thermal reactions of [NEt₄][Fe(CO)₄(AuNHC)] [NHC = IMes ([NEt₄][1]) or IPr ([NEt₄][2]); IMes = C₃N₂H₂(C₆H₂Me₃)₂; IPr = C₃N₂H₂(C₆H₃ⁱPr₂)₂], Fe(CO)₄(AuNHC)₂ [NHC = IMes (3) or IPr (4)], Fe(CO)₄(AuIMes)(AuIPr) (5), and Fe(CO)₄(AuNHC)(AuPPh₃) [NHC = IMes (6) or IPr (7)] were investigated in different solvents [CH₂Cl₂, CH₃CN, dimethylformamide, and dimethyl sulfoxide (dmso)] and at different temperatures (50-160 °C) in an attempt to obtain higher-nuclearity clusters. 1 and 2 completely decomposed in refluxing CH₂Cl₂, resulting in [Fe₂(CO)₈(AuNHC)]^- [NHC = IMes (10) or IPr (11)]. Traces of [Fe₃(CO)₁₀(CCH₃)]^- (12) were obtained as a side product. Conversely, 6 decomposed in refluxing CH₃CN, affording the new cluster [Au₃{Fe(CO)₄}₂(PPh₃)₂]^- (15). The relative stability of the two isomers found in the solid state structure of 15 was computationally investigated. 4 was very stable, and only after prolonged heating above 150 °C in dmso was limited decomposition observed, affording small amounts of [Fe₃S(CO)₉]^2- (9), [HFe(CO)₄]^- (16), and [Au₁₆S{Fe(CO)₄}₄(IPr)₄]ⁿ⁺ (17). A dicationic nature for 17 was proposed on the basis of density functional theory calculations. All of the other reactions examined led to species that were previously reported. The molecular structures of the new clusters 11, 12, 15, and 17 were determined by single-crystal X-ray diffraction as their [NEt₄][11]·1.5toluene, [Au(IMes)₂][15]·0.67CH₂Cl₂, [NEt₄][12], and [17][BF₄]_n·solvent salts, respectively.

Electronic and optical properties of [Au(CH3CSS)]4 cluster. A quantum chemistry study

The [Au(dta)]₄ (dta = dithioacetate, S₂CCH₃) cluster is modeled and the electronic and optical properties described.

A comparative interplay between small heterorings and hypofluorous acids

Through the B3LYP/6-311++G(d,p) calculations, theoretical studies of structural parameters, electronic properties, infrared vibration modes, and charge density topologies on the C2H4O∙∙∙HX and C2H5N∙∙∙HX (X = F or O-F) heterocylic hydrogen complexes are presented. The H-bond distances and high energies point out strong contacts and stable interactions in these complexes, and the relationships between the frequency shifts on the H-F and H-O bonds as well as O-F σ-holes with the interaction strength are the benchmarks of this current work. The computations of charge transfer amounts in light of the ChelpG and NBO approaches revealed a separation of charge density on the O-F σ-holes, whose statement is reinforced by the QTAIM descriptors. Despite that O∙∙∙H and N∙∙∙H H-bonds have been characterized as closed-shell interactions, qualitatively the appearance of a partial covalent profile also was unveiled by the QTAIM protocol.

Dinuclear planar chiral ferrocenyl gold(i) & gold(ii) complexes

The first scalemic ferrocenyl gold(i) and gold(ii) complexes have been prepared and structurally analysed by X-ray, (spectro)electrochemical and DFT studies.

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

We report a computational study 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 at the HF, MP2, DFT and DFT-D3 levels.