1H NMR (400 MHz, CDCl3) δ 7.77 (d, J = 8.6 Hz, 2H), 7.67 (d, J = 8.5 Hz, 2H), 7.58 – 7.50 (m, 4H), 7.46 – 7.36 (m, 6H). 13C{1H} NMR (101 MHz, CDCl3) δ 169.0, 136.5, 135.0, 130.2, 130.0, 129.6, 129.3, 128.7, 128.2, 126.2 (q, J = 3.7 Hz), 125.83.