Organic/Inorganic Complex Pigments: Ancient Colors Maya Blue
Maya Blue is an ancient blue pigment composed of palygorskite clay and indigo. It was used by the ancient Maya and provides a dramatic background for some of the most impressive murals throughout Mesoamerica. Despite exposure to acids, alkalis, and chemical solvents, the color of the Maya Blue pigment remains unaltered. The chemical interaction between palygorskite and indigo form an organic/inorganic complex with the carbonyl oxygen of the indigo bound to a surface Al{sup 3+} in the Si-O lattice. In addition indigo will undergo an oxidation to dehydroindigo during preparation. The dehydro-indigo molecule forms a similar but stronger complex with the Al{sup 3+}. Thus, Maya Blue varies in color due to the mixed indigo/dehydroindigo complex. The above conclusions are the result of application of multiple techniques (X-ray diffraction, differential thermal analysis/thermal gravimetric analysis, high resolution transmission electron microscopy, scanning electron microscopy, infrared and Raman spectroscopy) to the characterization of the organic/inorganic complex. A picture of the bonding of the organic molecule to the palygorskite surface forming a surface complex is developed and supported by the results of density functional theory calculations. We also report that other organic molecules such as thioindigo form similar organic/inorganic complexes thus, opening an entirely new class of complex materials for future applications.
- Research Organization:
- Stanford Linear Accelerator Center (SLAC)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 953873
- Report Number(s):
- SLAC-REPRINT-2009-519
- Journal Information:
- J. Inorg. Biochem 101:1958,2007, Journal Name: J. Inorg. Biochem 101:1958,2007 Journal Issue: 11 Vol. 101; ISSN JIBIDJ; ISSN 0162-0134
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BONDING
CARBONYLS
CLAYS
COLOR
COMPLEXES
DENSITY FUNCTIONAL METHOD
DIFFERENTIAL THERMAL ANALYSIS
DIFFRACTION
INDIGO
INTERACTIONS
MATERIALS
MOLECULES
OXIDATION
OXYGEN
Other
CHEM
BIO
PIGMENTS
RAMAN SPECTROSCOPY
RESOLUTION
SCANNING ELECTRON MICROSCOPY
SOLVENTS
SURFACES
THERMAL GRAVIMETRIC ANALYSIS
TRANSMISSION ELECTRON MICROSCOPY