Controlling intermolecular aurophilicity in emissive dinuclear Au(i) materials and their luminescent response to ammonia vapour

Abstract

The concept that hydrogen bonding cations can reduce the coulombic repulsion inherent to anionic gold species and thereby trigger aurophilicity is realized with three new photoluminescent compounds of the form [Q]2[Au2(i-mnt)2] (i-mnt = (CN)2C[double bond, length as m-dash]CS2(2-), Q = 3,5-dimethylpyrazolium, piperidinium). These compounds illustrate unprecedented supramolecular aurophilicity between the anions, the emission of which is significantly red-shifted compared to zero-dimensional analogues, a direct result of the aurophilic network. The piperidinium salt exhibits a vapochromic/luminescent response to ammonia, inducing a change in colour of the reflectance and emission from red to yellow. These results demonstrate the ability to rationally control the formation of supramolecular metallophilic networks via the incorporation of hydrogen bonding cations.

Coordination-based vapochromic behavior of a luminescent Pt(ii) complex with potassium ions

“…[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] In contrast, the Type II mechanism allows the generation of vapochromism from the direct coordination of vapor molecules to the chromophore, resulting in a change in the absorption/ emission energy. [23][24][25][26][27][28][29][30][31][32][33][34][35][36] Pt(II) complexes with Pt/Pt interactions (Type I mechanism) are promising candidates of vapochromic materials. Pt(II) complexes tend to form a one-dimensional stacking structure through the overlapping of the 5d z 2 orbitals of the Pt(II) ions.…”

“…Conversely, it is a common strategy for non-Pt(II) vapochromic complexes to provide a strong binding site, such as a coordination site, for vapor molecules to bind with the host molecules (including Type II mechanism). [23][24][25][26][27][28][29][30][31][32][33][34][35][36] Such binding sites would strongly stabilize the vapor-adsorbed state and probably enable us to clarify the vapor adsorption behavior. To extend this strategy to Pt(II) complexes, we focused on alkali metal ions, because these ions would act as coordination sites and can be introduced easily into the metal complex.…”

Molecular gold strings: aurophilicity, luminescence and structure–property correlations

“…[181][182][183][184] In this context, many gold string compounds are supported by bidentate dithiophosphate, 185-189 dithiocarboxylate, 190,191 diselenophosph(in)ate 192,193 or related ligand systems. [194][195][196][197][198][199] The Ch-X-Ch donor sites (Ch = chalcogenide, X = C, P) exhibit a low steric demand, which allows for the formation of gold strings comprising intermolecular connected homoleptic digold complexes (Fig. 23).…”

Luminescent gold–thallium derivatives with a pyridine-containing 12-membered aza-thioether macrocycle

“…The luminescence properties of heteronuclear gold(I) complexes featuring Au I ⋯Au I and/or Au I ⋯M metallophilic interactions [M = transition and post-transition closed-shell metal ions such as Ag I , Cu I and Tl I ] 1-10 are currently considered of great interest not only from a theoretical point of view [11][12][13] but also for their potential applications. [14][15][16][17][18][19][20][21][22][23][24][25] A great number of factors contribute to affect the photophysical properties of these compounds, making a rational structure-property design a very challenging task. However, the nature of the organic ligands used to support metallophilic interactions is fundamental in controlling the nuclearity of these complexes, the intermolecular inter-action patterns based on Au I ⋯M interactions in the crystal lattice, and, therefore, the optical properties.…”