Cyclic molecular materials based on [M2O2S2]2+ cores (M = Mo or W)

Area of Science:

• Inorganic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Conventional precursors are often limited in their application for synthesizing complex inorganic structures.
• The development of novel molecular architectures with tunable properties is a key area in modern chemistry.

Purpose of the Study:

• To demonstrate the synthesis of sophisticated inorganic rings and wheels using conventional precursors and a creative approach.
• To explore the formation of cyclic entities through the self-condensation of [M2O2S2]2+ fragments.
• To investigate the host-guest properties arising from the flexibility and adaptability of these inorganic rings.

Main Methods:

• Utilizing an acid-basic process for the self-condensation of [M2O2S2]2+ fragments.
• Employing guest species (neutral polar or anionic molecules) during synthesis to influence ring formation and cavity filling.
• Characterizing the resulting inorganic rings and their solid-state assembly into 3-D networks.

Main Results:

• Successful synthesis of a diverse family of inorganic rings and wheels with varying nuclearity, size, and shape.
• Demonstration of the cationic open cavity within the rings capable of encapsulating neutral polar (e.g., aquo ligands) and anionic molecules (e.g., phosphates, metalates).
• Observation of host-guest interactions where ring flexibility (deformation and nuclearity) adapts to the encapsulated substrate's size and coordination needs.
• Formation of striking 3-D networks in the solid state through cation-anion connections, with alkali cations organizing the anionic rings.

Conclusions:

• Conventional precursors, when creatively employed, can lead to the synthesis of complex inorganic ring and wheel structures.
• The synthesized inorganic cycles exhibit remarkable flexibility and dynamic properties, enabling tunable host-guest chemistry.
• These molecular rings self-assemble into intricate 3-D networks, highlighting their potential in materials science and supramolecular chemistry.