Photoluminescence and electronic structure of thallium(1+) dicyanoaurate(1-): evidence for relativistic effects in thallium-gold and gold-gold interactions

Abstract

Experimental results of a study of the photoluminescence of microcrystalline Tl[Au(CN)2] as a function of temperature (1.7-400 K) and magnetic field (0-6 T) are described. These results, along with relativistically modified extended Hückel calculations, provide evidence that covalent Tl-Au interactions alter its spectroscopic properties in comparison with isostructural Cs[Au(CN)2], Specifically, the absorption and luminescence of Tl[Au(CN)2] appear at lower energies than for Cs[Au(CN)2], and a comparison of the luminescence spectra and lifetimes for the two compounds reveals evidence for an increased rate of intersystem crossing in T1[Au(CN)2] relative to Cs[Au(CN)2], Both effects are reflective of covalent Tl-Au interactions in Tl[Au(CN)2]. The electronic structure calculations clearly demonstrate the covalency of both the Tl-Au and Au-Au interactions in Tl[Au(CN)2] and reveal specific orbital contributions responsible for these interactions. Relativistic effects are shown to play an important role in the Tl-Au and Au-Au bonding.

Structure-Correlated Dual Fluorescent Bands in BSA-Protected Au25 Nanoclusters

“…36 The emission band of Au(I) compound exhibits a blue shift with increasing temperatures due to an increasing Au(I)−Au(I) separation. 36,40 The relationship between the emission energy and the separation between Au(I)−Au(I) has been used to explain the photophysical properties of several Au(I) complexes in solid states. 35 In Au 25 NCs, it is expected that the six [−S−Au(I)−S−Au(I)−S−] staples can act as Au(I) complexes.…”

Structural and spectroscopic studies of 2,9-dimethyl-1,10-phenanthrolinium cation (DPH) with chloride, triflate and gold dicyanide anions. The role of H-bonding in Molecular recognition and enhancement of - stacking

“…The emission profile is very similar to the emission of the protonated ligand, and hence suggests that the frontier orbitals in this complex are largely ligand based with minimal effect from the metal contribution. Consistent with its structural feature, no emission assignable to Au-Au interaction [32][33][34][35] has been observed in compound 3. Three crystal structures of the pronated ligand, 2,9-dimethyl-1,10-phenanthrolin1ium (DPH) cation with selected counter anions (chloride, triflate, and gold dicyanide) are characterized crystallographically.…”

Cyanide-bridged bimetallic multidimensional structures derived from organotin(IV) and dicyanoaurate building blocks: ion exchange, luminescence, and gas sorption properties

“…Thus, the peak at 442 nm observed for 1 could be tentatively attributed to aurophilic interaction. As in the case of K[Au(CN) 2 ] and Tl[Au(CN) 2 ], the low-energy band at 670 nm in 1 is probably due to luminescence traps caused by imperfections in the microcrystalline sample [10,42]. The emission band at 670 nm (full width at half-maximum is 230 nm) is much broader than the peak at 442 nm (full width at halfmaximum is 100 nm), which gives an indication of longer lifetime of the low-energy band.…”

“…The unique ability of linear [Au(CN) 2 ] − anion to form Au-Au aurophilic interaction plays a key role in controlling the dimensionality and topology of these dicyanoaurate-based heterometallic polymers [4][5][6][7]. The cyanoaurate-based heterometallic polymers may exhibit unusual structural motifs and physical properties, such as luminescence [8][9][10][11], vapochromism [12,13], birefringence [14][15][16][17][18], colossal thermal expansion [19,20], magnetism [21][22][23][24][25] or ion exchange [26]. This dicyanoaurate anion also has significant importance in industrial and medical applications.…”