Syntheses and structures of two gold(i) coordination compounds derived from P–S hybrid ligands and their efficient catalytic performance in the photodegradation of nitroaromatics in water

Abstract

Solvothermal reactions of HAuCl₄·4H₂O with a P–S hybrid ligand N,N-bis(diphenylphosphanylmethyl)-amino-thiocarbamide (dppatc) at 80 °C and 115 °C produced two Au–P–S complexes, [Au₂(dppatc)₂]Cl₂ (1) and [Au₂(dppmt)₂]_n (2) (dppmtH = (diphenylphosphino)methanethiol). 1 and 2 were characterized by elemental analyses, IR and UV-vis spectra, thermal-gravity analyses, powder X-ray diffraction and single crystal X-ray diffraction analyses. Compound 1 contains a dinuclear [Au₂(dppatc)₂]²⁺ dication, while 2 has a one-dimensional chain formed by Au⋯Au aurophilic interactions. Compounds 1 and 2 exhibited excellent catalytic activity toward the photodegradation of nitrobenzene, p-nitrophenol and 2,4-dinitrophenol in aqueous solutions. The degradation reactions followed the zero-order kinetic model, in which the three nitroaromatics could be converted into CO₂ and H₂O in 92–96% yields.