Synthesis, structure and luminescent properties of three organogold(I)-9-ethynyl-anthracence-diphosphine complexes

Gold(I)–Alkynyl Complexes with an N‐Donor Heterocyclic Ligand: Synthesis and Photophysical Properties

“…The triplet emission that could be induced by a heavy‐atom effect, , in these complexes is absent despite the fact that the ligand chromophoric centre is localized in close proximity to the metal ion. However, examples of fluorescent heavy‐metal complexes exist in the literature, and there are a few gold(I) complexes, which display 1 IL singlet emission.…”

“…As a rule, the observed emission is phosphorescence due to the external heavy‐atom effect of the gold centre(s), which opens up access to the low‐lying emissive triplet state through the intersystem crossing (ISC). However, in complexes containing an independent chromophoric centre based on an extended aromatic system, emission from the initial singlet excited state may compete with ISC, which results in the generation of either dual singlet/triplet emission, or only singlet emission from an organic chromophore . These unusual types of photophysical behaviours are strongly determined by the nature of the ligand and the coordination‐sphere geometry, namely by the distance between the metal ion and the organic chromophore, which is a crucial parameter for effective spin‐orbit coupling and consequently for the ISC rate.…”

Dinuclear Diphosphine Complexes of Gold(I) Alkynyls, the Effects of Alkynyl Substituents onto Photophysical Behavior

“…Alkynyl‐phosphine gold(I) complexes based on mono‐ and polyphosphine ligands attract considerable attention due to their rich structural chemistry and unique photophysical properties, which are determined by the nature of the alkynyl ligands, formation of inter‐ and intramolecular aurophilic bonds and by spin‐orbit coupling (SOC), the latter being of particular importance for such heavy coordination center as gold atom. It is well documented that coordinated {C≡C–R} moieties containing various aromatic substituents play a key role in emission of these compounds because of the ligand π* orbitals involvement into emissive excited states of various nature: 1 IL(π–π*), 3 IL(π–π*), 3 MLCT, and 3 MMLCT. Depending on the nature of alkynyl ligand substituents the complexes of this type may display either phosphorescence or dual phosphorescence from the triplet excited states: 3 IL(π–π*), 3 MLCT, and 3 MMLCT.…”

“…Depending on the nature of alkynyl ligand substituents the complexes of this type may display either phosphorescence or dual phosphorescence from the triplet excited states: 3 IL(π–π*), 3 MLCT, and 3 MMLCT. For the complexes containing alkynyls decorated with bright fluorophores (anthracene, fluorene, benzothiadiazole, boranil) it is possible to observe fluorescence from 1 IL(π–π*), which however may be accompanied with the phosphorescence from various triplet excited states mentioned above. In the latter case relative intensity of these two components is strongly determined by the SOC value, which depends on the distance between organic chromophore and gold ion as well as on the degree of metal orbitals participation in the emissive triplet state , , .…”

“…In this class of compounds the polyphosphine derivatives are of particular interest because in crystal state they often form supramolecular structures with the networks of intermolecular noncovalent bonds, which affect strongly the photophysical characteristics of the solid state samples , , , , , , , , . Dinuclear diphosphine complexes of gold(I) alkynyls based on the diphosphines with flexible skeleton are well‐known, though the compounds studied by the present time mainly comprise aliphatic or pyridine‐based substituted alkynyl ligands , , , , , with only a few examples of phenyl‐based aromatic substituents , , , . In this work we focused on the synthesis, structural characterization and photophysical study of bis(diphenylphosphanyl)ethane/propane gold(I) complexes, which display extremely different photophysical behavior in solution and in solid state depending on the nature of aromatic substituents (biphenyl, pyrene and azobenzene) in the alkynyl ligands.…”