Luminescent gold complexes

In the solid state, the complexes exhibit a yellow-green luminescence under UV irradiation (365 nm). All the emission spectra are similar and consist of three broad emissions above 370 nm (e.g., 384, 490 and 524 nm for m = 10, w = 6), while the free isocyanides (white solids) are luminescent giving one strong emission band with its maximum at about 360 nm. In dicMoromethane solution both the free isocyanides and their gold complexes are luminescent too, but only one intense emission is observed for the complexes in the range of 345-387nm (Figure 8.14). The lifetime... 

Arias, J., Bardaji, M. and Espinet, P. (2008) Luminescence and Mesogenic Properties in Crown-Ether-Isocyanide or Carbene Gold(I) Complexes Luminescence in Solution, in the Solid, in the Mesophase, and in the Isotropic Liquid State. Inorganic Chemistry, 47, 3559-3567. 

Many gold(I) complexes are susceptible of having optical properties and consequently in the last few years several reports have dealt with luminescence in gold complexes.34,42,43 It has been shown... 

Luminescent, trinuclear-mixed dithiocarbamato-xanthato gold complexes, [Au3Cl(S2CNR2)(S2COEt)(p-dpmp)] where R = Me, CH2Ph and dpmp = fe(diphenylphosphinomethyl)phenylphosphine, PhP(CH2PPh2)2 have been prepared and their optical properties were investigated.398... 

Of all these, the only permitted electronic transition is1 Do < 1S0, while the rest are forbidden according to the spin rule, leading to phosphorescent emissions. However, these are precisely the ones responsible for the emissions found in many luminescent gold complexes, appearing in a range between 500 and 700 nm (665 nm in the gaseous ion). 

As observed in these last examples and in spite of the above-mentioned foreseeable simplicity of the conditions that a gold complex requires to display luminescence,... 

As shown in this example, although the structure displayed a complexity not found in the previous examples, the assignment of the origin of the luminescence did not differ much from simpler sulfur-gold complexes in less aggregated systems. 

In all cases the complexes were strongly luminescent at room temperature, in contrast to the precursor homonuclear derivatives, and at an energy that was tunable, displaying a site-selective excitation that depended on the Au Ag molar ratio, lying between the emission bands of the pure Ag and Au compounds. For instance, while the homonuclear derivative La[Ag(CN)2]3 emitted at 77 K at 345 and 470 nm (exc. 310 nm) and the gold complex La[Au (CN)2]3 at 431 and 493 nm (exc 310 nm), the mixed metal systems tended toward Ag or Au peak positions, depending on loading. 

Earlier articles that cover related information are available, and these form a background for the present contribution [3,4], As this article will demonstrate, gold complexes display an interesting array of luminescent properties that are frequently difficult to anticipate. This reviewer believes that there are still many interesting discoveries to be made in this ever-surprising field. 

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