The synthesis procedure for Tetrakis-(4-nitrophenyl)methane: Tetraphenylmethane (4.8g, 15.0 mmol) was slowly added to fuming nitric acid (25 ml) stirred rigorously in a salt/ice bath of ~-5°C. Then, a mixture of acetic anhydride and glacial acetic acid (1:2, 25 ml) was added slowly to the mixture. After stirring at -5°C for 15 min, glacial acetic acid (80 ml) was added, and the suspension was further stirred for 5 min. The mixture was filtered on a glass frit, washed with acetic acid (2 x 100 ml), methanol (2 x 100 ml), and chilled tetrahydrofuran (2 x 50 ml) and dried in vacuo to afford a cream color solid (3.2 g, 43% yield).
