Insights into Molecular Structures and Optical Properties of Stacked [Au-3(RN=CR ')(3)](n) Complexes
| Autor: | Dage Sundholm, Mohammad A. Omary, Stefan Taubert, Hassan Rabaâ |
|---|---|
| Přispěvatelé: | Department of Chemistry |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Steric effects
Dimer Cyclohexane conformation 116 Chemical sciences Electronic structure 010402 general chemistry 01 natural sciences 114 Physical sciences Inorganic Chemistry DENSITY-FUNCTIONAL THEORY chemistry.chemical_compound AUROPHILIC INTERACTIONS Physical and Theoretical Chemistry Triplet state IDENTITY APPROXIMATION 010405 organic chemistry HARTREE-FOCK 0104 chemical sciences Crystallography ELECTRONIC-STRUCTURE Coupled cluster chemistry EXCITED-STATES AUXILIARY BASIS-SETS Excited state LUMINESCENCE MODEL CC2 Density functional theory TRINUCLEAR GOLD(I) COMPLEXES |
| Popis: | The molecular structure of stacked cyclic trinuclear gold(I) complexes [Au-3(RN=CR'(3)](n), with n = 1-4, where R = H, methyl (Me), cyclopentyl ((c)Pe), and phenyl (Ph) and R' = OH and methoxy (OMe) were studied computationally at the second-order Moller-Plesset (MP2) and density functional theory (DFT) levels of theory. At the DFT level, the aurophilic and dispersion interactions were accounted for by using the TPSS functional in combination with the semiempirical D3 correction. The structure optimizations yielded the lowest energy for a slided stacked structure of the [Au-3(HN=COH)(3)](2) dimer, where monomers are slightly shifted relative to one another. At the MP2 level, the slided structure is 32 kJ/mol more stable than the staggered dimer structure, which in turn is energetically 11 kJ/mol below the eclipsed structure. The calculations show that aromatic ligands lead to a planar and prismatic structure of [Au-3(PhN=COMe)(3)](4), whereas for [Au-3('PeN=COMe)(3)](4), a chair conformation is obtained due to steric effects. Excitation energies were calculated for [Au-3(RN=CR')(3)] and [Au-3(RN=CR'(3)](2) with R = H, Me, and 'Pe and R' = OH and OMe at the time-dependent DFT level using the optimized molecular structures of the singlet ground state. To simulate the luminescence spectra, the lowest triplet excitation energy was also calculated for the molecular structure of the lowest triplet state. The calculated excitation energies of [Au-3(HN=COH)(3)] and [Au-3(HN=COH)(3)](2) are compared with values obtained at the approximate singles and doubles coupled cluster (CC2) and the second-order algebraic diagrammatic construction (ADC(2)) levels of theory. The calculated absorption and emission energies reproduce the experimental trends, with extremely large Stokes shifts. A solvoluminescence mechanism is also proposed. |
| Databáze: | OpenAIRE |
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