Cyclic trimeric perfluoro-o-phenyleneinet-cury (o-C6F4Hg)(3) (1) exhibits a high catalytic activity in the phase transfer nitration of various aromatic substrates (2-methyinaphthalene, 1,3- and 2,6-dimethylnaphthalenes, acenaphthene, anthracene, pyrene) with dilute nitric acid in the presence of sodium nitrite as an initiator and sodium chloride as a promoter. The reactions proceed at room temperature in good or close to quantitative yields. In the absence of the catalyst, the rate of the process is sharply diminished. The best results in the nitration were obtained on using benzene-nitrobenzene mixtures as the organic phase. The replacement of the PhH/PhNO2 mixtures by benzene decreases the reaction rate. An important role in these reactions is played by sodium chloride in the absence of which the catalyst completely loses its activity. Mercury dichloride and bis(perfluorophenyl)mercury do not catalyse the phase transfer nitration with dilute nitric acid even in the presence of sodium chloride. The mechanism of the promoting influence of NaCl on the process of the nitration is discussed. The ability of inacrocycle 1 to catalyse the proton transfer from an aqueous phase to an organic phase is also reported. (c) 2005 Elsevier B.V. All rights reserved.