1 H NMR ( 300 MHz , CDCl 3 ) : δ 0 . 25 - 0 . 39 ( s , 18 H ) , 0 . 45 - 0 . 91 ( m , 90 H ) , 2 . 00 - 2 . 08 ( m , 12 H ) , 7 . 4 - 7 . 52 ( d , 2 H , J = 2 . 46 Hz ) , 7 . 52 - 7 . 65 ( m , 10 H ) , 7 . 69 - 7 . 71 ( d , 2 H , J = 0 . 61 Hz ) , 7 . 74 - 7 . 8 ( m , 4 H ) .