“Bottle-around-a-ship” confinement of high loadings of Acridine Orange in new aluminophosphate crystalline materials

Abstract

Acridine Orange has been used as the unique organic structure-directing agent in the synthesis of three new aluminophosphate crystalline materials with high loadings of dye (28, 27 and 25%). The occluded organic molecule is protonated, and at least in one solid (phase C), diprotonated cations may also exist, as suggested from charge balance considerations. The aluminophosphate framework lacks full connectivity of tetrahedra, since the presence of both fully condensed and partially uncondensed PO₄ tetrahedra was revealed by ³¹P MAS MMR spectroscopy. Al is in octahedral and tetrahedral environments, and in one of the materials (phase C), pentacoordinated Al was also found by ²⁷Al MAS NMR spectroscopy. The three colourful solids show distinct visible spectra with bands due to aggregates containing both H and J components. The solids fluoresce at a wavelength close to the J band and also at longer wavelengths.