Dye No.

Yield (%)

Melt pt. (˚C)

UV-visible Spectroscopy

Selected frequency

λmax(nm)

ε × 104 (mol−1・cm−1)

1

60.7

138

500

4.9729

OH 3747, 3245: -C-H 3090, 2972,

2853: -N=N- 1550, 1587: -COOH

1792, 1665: -N=O 1550

2

77.9

170 - 172

420

3.9418

OH 3744: -C-H 3087, 2969, 2853

-N=N- 1442: -N=O 1559.

3

40.9

152

505

5.4242

OH 3739, 3235: -C-H 2969, 2854:

-N=N- 1552, 1587: -N=O 1552:

-SO3H 1101, 1142.

4

88.5

129 - 131

425

4.5970

OH 3188: -C-H 3078, 2968: -N=N-

1589: -N=O 1514: -NO2 1332.

5

85.1

152 - 153

440

4.4910

OH 3745, 3244: -C-H 3090, 2972:

-N=N- 1551, 1589: -N=O 1551:

-SO3H 1139, 1231.

6

83.0

117 - 119

415

4.1549

OH 3616, 3367: -C-H 3068: -N=O

1458, 1509: -OCH3 2840, 2941.

7

59.0

147 - 149

510

5.1206

OH 3724, 3244: -C-H 3090, 2972:

-N=N- 1553, 1587: -N=O 1434:

-SO3H 1142, 1232.

8

85.0

146 - 148

560

2.8139

OH 3204: -C-H 3083: -N=O 1436,

1561