Novel gold(i) diphosphine-based dimers with aurophilicity triggered multistimuli light-emitting properties

Abstract

aWe report a design strategy for preparation of stimuli-responsive materials with multicolour emission that is based on a single type of luminophore molecule comprising gold(I) and flexible diphosphine ligand. The multistimuli-responsive luminescent dinuclear [Au2(dpephos)2](X)2 (dpephos = bis(2-diphenylphosphino)-phenyl ether; X = NO3, 1; CF3SO3, 2; BF4, 3; PF6, 4; SbF6, 5) complexes were obtained by rapid mechanochemical syntheses. The single crystal X-ray diffraction analysis of complexes 1-5 revealed that the [Au2(dpephos)2] 2+ cations do not exhibit short intramolecular aurophilic interaction. Supported by the structural flexibility of the dpephos ligand, these intramolecular Au···Au contacts are highly sensitive to external stimuli, such as light, temperature, mechanical grinding and exposure to solvent vapours. The ensuing materials, which comprise only gold(I)-diphosphine luminophores, can emit green, yellow and red or red colour, and the colour of the emitted light can be switched by light, heat or pressure. A change from green to yellow in the emission was observed upon heating to room temperature under the excitation with 365 nm, whereas a change from yellow to red was achieved by mechanical grinding. Moreover, the green emission can be switched to red by changing the excitation wavelength to 312 nm. All these reversible luminescence colour changes are readily perceivable by naked eye, and they are attributed to small structural modifications induced by external stimuli that also modulate the intramolecular Au···Au interaction. The red emission from these gold(I) diphosphine-based dimers can be attributed to the presence of intramolecular aurophilic interaction.

Excimer and Exciplex Formation in Gold(I) Complexes Preconditioned by Aurophilic Interactions

“…This work has provided early evidence that the emission properties show a dependence on the Au⋅⋅⋅Au distance in the crystals . The phenomena presently under investigation include many more diverse fields, such as thermo‐, photo‐, mechano‐, solvato‐, and vapochromism under standard or extreme pressures, where gold(I) compounds with intra‐ or intermolecular Au⋅⋅⋅Au contacts are found to show all kinds of multi‐stimuli‐induced light‐emitting properties …”

“…[18] Thep henomena presently under investigation include many more diverse fields,s uch as thermo-, photo-, mechano-, solvato-, and vapochromism under standard or extreme pressures,w here gold(I) compounds with intra-or intermolecular Au•••Aucontacts are found to show all kinds of multi-stimuli-induced light-emitting properties. [19][20][21][22] Thec hemical reactivity of gold(I) compounds is also strongly influenced by aurophilic interactions because they lead to arrangements that allow for direct di-or multicenter reaction pathways.Scheme 1shows examples of transannular oxidative addition to dinuclear gold(I) complexes (d 10 -d 10 ) affording long-sought gold(II) complexes (d 9 -d 9 )orproducts with mixed oxidation states (X, Y = halogen;X 2 = disulfide RSSR;CH 2 Cl 2 ). [23][24][25] Form ononuclear gold(I) complexes,r elated phenomena in solution are rare because the weak aurophilic interactions can easily be overruled by efficient solvation of the mononuclear units.H owever,a th igh concentrations of the complexes,and at low temperatures,the number of aurophilicitybased dimers or oligomers is increased, and the association can be detected by various analytical techniques and in particular by following the UV/Vis absorption and emission properties.…”

Dinuclear Gold Complexes Supported by Wide Bite Angle Diphosphines for Preorganization-Induced Selective Dual-Gold Catalysis

“…Basic coordination chemistry of these potentially dinucleating ligands toward gold has already been established by several groups [30][31][32]. Furthermore, Koshevoy et al investigated the formation and photochemical properties of bis-gold complexes with the related ligand Xantphos [33][34][35][36][37][38]. We herein report on the formation of μ-chlorido and σ,π-alkynide derivatives of Au2Cl2(κ 2 -P;P-DBFPhos) and Au2Cl2(κ 2 -P;P-DPEPhos) and catalytic activity of these well-defined dinuclear species vs. mononuclear benchmarks in the intramolecular hydroamidation of functionalized amido-alkenes.…”

Excimer‐ und Exciplex‐Bildung in durch aurophile Wechselwirkungen präkonditionierten Gold(I)‐ Komplexen

“…Die Prototypen der aurophilen Bindung wurden in der Einleitung vorgestellt ( A – F ) . In allen Fällen werden die Goldatome auf Sub‐van‐der‐Waals‐Abstände aneinander geführt, sobald die sterischen Voraussetzungen des Systems eine derartige Annäherung erlauben.…”