Revisited UV- spectra of chlorohydroxoaurate anions.

The most important ionic precursor of gold, [AuCl] is used in aqueous solution leading to chlorohydroxoaurates species, [AuCl(OH)] (x = 1-4) due to partial hydrolysis. Their UV spectral signatures are still relatively unknown though very useful in many domains of application. Individual spectra of each of them are determined for the first time thanks to a thorough experimental investigation comprising the range 200-250 nm, surpringly ignored up to now. New isosbestic points useful for species partition analysis are evidenced. Electronic transition attribution is obtained from quantum chemical calculations based on TD-DFT. The prediction of the experimental blueshifted bands of the [AuCl(OH)] anions was possible only after applying energy corrections calibrated on the full UV range two-band spectrum of the [AuCl] complex.