Evidence of Topological Indigo/Dehydroindigo Isomers in Maya Blue-Like Complexes Prepared from Palygorskite and Sepiolite

摘要: Association of indigo to palygorskite and sepiolite phyllosilicates, forming Maya Blue-like systems, is studied by means electron microscopy, solid-state multinuclear magnetic resonance (1H−13C CP MAS, 27Al, 29Si NMR), visible infrared spectroscopies (ATR-FTIR, VIS), solid state electrochemistry. Combination such techniques suggest that Blue must be viewed as a complex polyfunctional organic−inorganic hybrid material in which different topological isomers dehydroindigo molecules, distributed the surface framework clay channels, suggested size-excluding electrochemical experiments, are involved. Such can tentatively assigned dye−clay interactions involving hydrogen bonding with interaction Mg2+ Al3+ ions mediated structural water dye molecules silanol units clay.