Macrocyklistienlike

Macrocyklistienlike is a neologism that has appeared in recent literature to describe molecular motifs that are macrocyclic in character but do not conform to the strict criteria of classical macrocycles. The term blends the concept of macrocyclicity with a suffix that signals likeness, and it is used mainly in discussions of supramolecular design and ligand engineering. Because it is not universally adopted, definitions vary between sources.

Typically, macrocyklistienlike structures feature large ring-like backbones, often exceeding 12-atom rings, with multiple heteroatoms such as nitrogen, oxygen, or sulfur positioned to participate in coordination or hydrogen bonding. They may include fused, interrupted, or nonconventional linkages, and can exhibit conformational flexibility that allows adaptation to guest molecules or metal centers. The architecture often yields a defined internal cavity or binding pocket, yet the overall ring may be accessible or dynamic rather than rigid.

Synthetic approaches include macrocyclization strategies, templating with metal ions or π-systems, and modular assembly from smaller building blocks. Characteristic properties include strong host–guest interactions, potential for selective coordination chemistry, and sometimes attractive optical or electronic features such as fluorescence or charge-transfer behavior.

Applications discussed in the literature focus on supramolecular sensing, catalysis, and delivery platforms, where macrocyklistienlike motifs can stabilize reactive intermediates or recognize specific guests. The concept overlaps with established families such as macrocycles, calixarenes, cucurbiturils, and expanded porphyrins, though macrocyklistienlike is used to emphasize noncanonical ring designs.

Status and acceptance of the term remain informal. Because the definition is not standardized, researchers typically specify structural criteria within their work when invoking macrocyklistienlike. Critics argue that the term may blur distinctions between well-defined macrocyclic ligands and related supramolecular motifs, underscoring the need for clearer nomenclature.