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	𝜆^maxH𝑛L, nm	𝜆^maxM(H𝑥L)𝑞, nm	Δ𝜆, nm	Changes of absorbance at 𝜆^max
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	—