1 H NMR ( 300 MHz , CDCl 3 ) : δ 0 . 28 - 0 . 33 ( s , 18 H ) , 0 . 45 - 0 . 57 ( m , 28 H ) , 0 . 64 - 0 . 90 ( m , 32 H ) , 2 . 06 - 2 . 08 ( m , 8 H ) , 4 . 04 ( s , 2 H ) , 7 . 47 - 7 . 50 ( d , 2 H , J = 1 . 38 Hz ) , 7 . 54 ( s , 2 H ) , 7 . 61 - 7 . 71 ( m , 10 H ) , 7 . 76 - 7 . 78 ( d , 2 H , J = 2 . 1 Hz ) , 7 . 78 ( s , 2 H ) , 7 . 88 - 7 . 90 ( d , 2 H , J = 0 . 9 Hz ) .