摘要 |
Asymmetrical 1:2 chromium complex dyes of formula (I), wherein X signifies -SO3M, -SO2NR1R2 or chlorine, Y signifies hydrogen, -SO3M or chlorine, R1 signifies hydrogen, C1-6alkyl, C2-3-hydroxyalkyl or a radical of formulae (a) or (b), R2 signifies hydrogen, C1-6alkyl or C2-3-hydroxyalkyl, or R1 and R2 together with the nitrogen atom to which they are attached, form a 5- or 6-membered saturated heterocycle, R3 signifies hydrogen, C1-2-alkyl, chlorine, -COOM or -SO3M, R4 signifies hydrogen, C1-2-alkyl, C1-2-alkoxy chlorine or -SO3M, n signifies from 0 to 3, M signifies in each case hydrogen or a nonhromophoric cation, and M<+>signifies hydrogen or a nonchromophoric cation, are useful for dyeing artificially produced oxide layers on aluminium or aluminium alloys, on which they produce grey dyeings in high color yield and hue reproducibility |