The synthesis of triethylphosphine gold(I) 4-nitrobenzenethiolate and solvent dependent visible absorption spectra of 4-nitrobenzenethiolate

The synthesis of triethylphosphine gold(I) 4-nitrobenzenethiolate, Et3PAu(SC6H4NO2-4), is reported. Et3PAu(SC6H4NO2-4) displays a low energy visible electronic absorption band which is solvent dependent: EtOH (λmax = 385 nm), acetonitrile (λmax = 391 nm), THF (λmax = 395 nm), and DMSO (λmax = 402 nm). The corresponding low energy visible electronic absorption band of 4-nitrobenzenethiolate, 4-NO2C6H4S− also shows solvent dependency: acetonitrile, (λmax = 484 nm), DMSO (λmax = 502 nm), dimethylformamide (λmax = 505 nm). The positive solvatochromic shifts for Et3PAu(SC6H4NO2-4) and 4-NO2C6H4S− are consistent with an intraligand (IL) charge transfer transition, i.e. π(S) → ∗π (C6H4NO2-4) or n(S) → ∗π (C6H4NO2-4). Assignment of 4-NO2C6H4S− was aided by a DFT calculation.