Research Article
Reactions of o,o′-Dihydroxy Azo Dyes with the Third Group M(III) Ions: A Spectroscopic and Electrochemical Study
Table 1
Spectroscopic characteristics of M(III)-azo dye systems.
| Metal | pH | , nm | , nm | Δ, nm | Changes of absorbance at |
| Eriochrome red B | Al | 8.0 | 470 | 488 | 18 | Decreased | Sc | 8.0 | 470 | 496 | 26 | Decreased [16] | Ga | 4.5 | 465 | 500 | 35 | Increased substantially | 8.0 | 470 | 502 | 32 | Decreased [16] | In | 8.0 | 470 | 494 | 24 | Decreased [16] | Tm | 8.0 | 470 | 484 | 14 | Decreased [16] |
| Calcon | Al | 4.9 | 520 | 550 | 30 | Increased | Sc | 4.9 | 520 | 520 | 0 | Decreased | Ga | 4.9 | 520 | 550 | 30 | Increased | In | 4.9 | 520 | 520 | 0 | Decreased | Y | 4.9 | 520 | 510 | 0 | Decreased |
| Kalces
| Al | 5.5 | 550 | 570 | 20 | Increased | Sc | 9.5 | 560 | 520 | 40 | Decreased | Ga | 4.5 | 550 | 570 | 20 | Increased | In | 4.6 | 550 | 560 | 10 | Decreased | Y | 9.5 | 560 | 520 | 40 | Decreased |
| Eriochrome black T | Al | 4.0 | 520 | 540 | 20 | Increased | Sc | 5.5 | 510 | 540 | 30 | Increased substantially | Ga | 4.5 | 520 | 550 | 30 | Increased substantially | In | 8.5 | 590 | 550 | 40 | Decreased |
| Eriochrome blue SE | Al | 5.0 | 520 | 540 | 20 | Increased | 8.0 | 530–560 (wide maximum) | 530 | — | Increased | Sc | 6.1 | 530 | 550 | 20 | Decreased | Ga | 7.0 | 530 | 550 | 20 | Decreased | In | 4.4 | 520 | 530 | 10 | Decreased | 7.0 | 530 | 550 | 20 | No changes | Sm |
7.9 |
530–560 (wide maximum) | 540–550 | — | Increased | Nd | 2 maxima at 530 and 550 | — | Dy | 530–550 | — |
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