General procedure for the synthesis of 9,10-bis(diethylphosphinomethyl)anthracene from 9,10-bis(chloromethyl)anthracene and triethyl phosphite: 9,10-bis(chloromethyl)anthracene (7.8 g, 28.3 mmol) was mixed with triethyl phosphite (30 mL), and the reaction mixture was vigorously stirred under mild reflux conditions overnight. Upon completion of the reaction, the excess triethyl phosphite was removed by distillation under reduced pressure. The crude product was purified by silica gel column chromatography using ethyl acetate/petroleum ether (1:1, v/v) as eluent. A yellow solid product (10.4 g, 76.8% yield) was finally obtained. The structure of the product was confirmed by 1H NMR (500 MHz, CDCl3): δ 8.32 (d, 4H), 7.53 (d, 4H), 4.21 (d, 8H), 3.78 (d, 4H), 1.11 ppm (t, 12H).
