Host-guest adaptability within oxothiomolybdenum wheels: structures, studies in solution and DFT calculations

Area of Science:

• Supramolecular Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Host-guest chemistry explores the interactions between molecular hosts and guests.
• Molybdenum-sulfur clusters are known for their diverse structural and electronic properties.
• Self-condensation reactions offer a pathway to construct complex molecular architectures.

Purpose of the Study:

• To synthesize and characterize novel host-guest cyclic architectures using [Mo(2)O(2)S(2)](2+) oxothiocations and dicarboxylate anions.
• To investigate the influence of dicarboxylate guest structure on the host-guest dynamics and stability.
• To explore the adaptability and selective encapsulation capabilities of these supramolecular systems.

Main Methods:

• Synthesis of [Mo(12)Adip](2-), [Mo(12)Sub](2-), and [Mo(14)Azel](2-) complexes.
• Solid-state characterization using X-ray diffraction.
• Solution-state analysis via (1)H NMR and DOSY experiments in various solvents.
• Experimental determination of relative stabilities.
• Theoretical DFT investigations.

Main Results:

• Successful formation of host-guest cyclic architectures with adipate, suberate, and azelaate anions.
• Host-guest dynamics are influenced by the nature of the host and guest, particularly anion charge.
• Relative stabilities of twelve-membered rings decrease in the order [Mo(12)Adip](2-) > [Mo(12)Pim](2-) > [Mo(12)Sub](2-).
• Host-guest adaptability and selective encapsulation are dependent on the guest's carbon chain length.
• DFT calculations confirm experimental observations regarding conformation, symmetry, and stability.

Conclusions:

• The self-condensation of [Mo(2)O(2)S(2)](2+) oxothiocations provides a versatile route to host-guest cyclic architectures.
• The study demonstrates tunable host-guest interactions governed by mutual adaptability and guest structure.
• These findings contribute to the understanding of selective molecular recognition and encapsulation in supramolecular chemistry.