Alizarin-aluminum-calcium complex

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Structural formula
Structure of the alizarin aluminum complex
General
Surname Alizarin-aluminum-calcium complex
other names
  • Aluminum (III) -1,2-dihydroxyanthraquinone complex
  • Calcium aluminum alizarinate
  • Alizarin madder (Al)
  • Turkish red
  • Pigment Red 83: 1 (CI 58000: 1)
Molecular formula [(Al (OH) (C 14 H 6 O 4 ) 2 Ca) 2 ]
External identifiers / databases
CAS number 104074-25-1
EC number 600-518-2
ECHA InfoCard 100.126.011
Wikidata Q2647300
properties
Molar mass 1118.91 g / mol
Physical state

firmly

safety instructions
GHS hazard labeling
no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

The aluminum-calcium complex salt of alizarin is a representative of the madder lakes , which are considered to be traditional coloring agents .

It is a monometallic chelate complex that is formed from alizarin molecules as ligands and aluminum and calcium ions as central particles by laking .

The structural proposal by Kiel and Heertjes (1963). is still often adopted or varied (e.g.) by today's literature, but has not yet been clarified with certainty. Recent studies have shown that these previous models were wrong. In the current model by Wunderlich and Bergerhoff , a multinuclear, bridged complex is proposed for the molecule in which two aluminum atoms and two calcium atoms are chelated by 4 alizarin molecules. In addition, the metal atoms are connected to one another by oxo bridges. Since the calcium-aluminum complex of alizarin is not electrically neutral, two protons per molecule must still be present in the structure for charge equalization. However, the position of the protons in the complex has not yet been determined.

use

The red pigment alizarin madder

In environmental terms, aluminum complexation by alizarin and its derivatives can be used to easily and inexpensively detect dissolved aluminum ( toxic ) in drinking water.

The complex is a traditional red coloring pigment that is available in retail outlets under the name "Alizarin dark madder". It is mainly used as an artist's paint and as a printing ink for food packaging.

Individual evidence

  1. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
  2. ↑ EC Kiel, PM Heertjes: Metal complexes of alizarin. I. The structure of the calcium-aluminum lake of alizarin. In: J. Soc. Dyers Col. Volume 79, 1963, pp. 21-27.
  3. ^ A b W. Herbst, K. Hunger: Industrial Organic Pigments. Production, properties, applications. 3. Edition. Wiley-VCH, Weinheim 2004, ISBN 3-527-30576-9 .
  4. ↑ V. Ya. Fain et al: Metal Complexes with Alizarin and Alizarin Red S: Electronic Absorption Spectra and Structure of Ligands. In: Russian Journal of Coordination Chemistry. Volume 30, No. 5, 2004, pp. 365-370.
  5. ^ EJ Tiedemann, Y. Yang: Fiber-save extraction of red mordant dyes from hair fibers. In: Journal of the American Institute of Conservation (JAIC). Volume 34, No. 3, 1995, pp. 195-206.
  6. ^ H. Zollinger: Color Chemistry. Syntheses, Properties, and Applications of Organic Dyes and Pigments. 3. Edition. VHCH, Zurich 2003, ISBN 3-906390-23-3 , p. 255.
  7. ↑ C.-H. Wunderlich, G. Bergerhoff: Constitution and color of alizarin and purpurin lakes. In: Chemical Reports. Volume 127, 1994, pp. 1185-1190.
  8. ↑ S. Bi, Z. Zhang: AC Oscillopolarographic determination of aluminum in natural and drinking waters using the adsorption of the Al (III) -1,2-Dihydroxyanthraquinone-3-sulfonic acid complex. In: Collect Czech Chem Commun . Volume 61, 1996, pp. 1745-1753, doi: 10.1135 / cccc19961745 .
  9. ↑ Safety data sheet according to 2001/58 / EC on Alizarin dark madder. Kremer Pigments 2009.