Beyond Nitrogen OSDAs

The use of organic structure-directing agents (OSDAs) is perhaps the most important factor to be considered for the synthesis of zeolitic materials. Several OSDAs had been used along the last 70 years, especially ammonium organic cations, letting the synthesis of a large number of materials. But besides ammonium cations, organic cations with different chemical natures had also been used, which resulted in the synthesis of very interesting zeolitic materials. This review includes most of the non-ammonium cations used up to date, namely, phosphorous cations, sulfonium cations, crown macrocycles and metal complexes, but also when N-containing OSDAs play a different role than in conventional zeolite syntheses, such as proton sponges, self-assembled compounds or ionic liquids.