Molecular Engineering of Noncovalent Dimerization

Abstract

Dimers are probably the simplest model to facilitate the understanding of fundamental physical and chemical processes that take place in much-expanded systems like aggregates, crystals, and other solid states. The molecular interplay within a dimer differentiates it from the corresponding monomeric state and determines its features. Molecular engineering of noncovalent dimerization through applied supramolecular restrictions enables additional control over molecular interplay, particularly over its dynamic aspect. This Perspective introduces the recent effort that has been made in the molecular engineering of noncovalent dimerization, including supramolecular dimers, folda-dimers, and macrocyclic dimers. It showcases how the variation in supramolecular restrictions endows molecular-based materials with improved performance and/or functions like enhanced emission, room-temperature phosphorescence, and effective catalysis. We particularly discuss pseudostatic dimers that can sustain molecular interplay for a long period of time, yet are still flexible enough to adapt to variations. The pseudostatic feature allows for active species to decay along an alternate pathway, thereby spinning off emerging features that are not readily accessible from conventional dynamic systems.

Helical Trilayer Nanographenes with Tunable Interlayer Overlaps

“…Recently, some molecular analogues of multilayer graphenes were synthesized by stacking nanographene sheets into multilayer structures. Nanographenes, whose structure bridges infinite 2D graphene and small polycyclic aromatic hydrocarbons (PAHs), provide a molecular model for graphenic materials. − The stacked nanographenes have shown distinguished electronic and optical properties, including enhanced photoluminescence, stabilized exciton, chirality, and sonosensitization. − …”

Metal–Organic Dimerization of Dissymmetrical Ligands toward Customized Through-Space Chromophore Interactions

“…34,35 According to the level of dynamics and the nature of linkages, most dimers can be assigned to three categories: (i) dynamic noncovalent dimers, (ii) pseudostatic noncovalent dimers, and (iii) static covalent dimers. 36 These reported dimers have shown great applications in the fields of enhanced emission, 37,38 roomtemperature phosphorescence, 39,40 supramolecular catalyst, 41,42 and near-infrared probes. 43 However, there are still some great challenges remaining: (i) Modulation of the spatial alignments of chromophores within the dimer is not easy.…”

“…Dimers are probably the simplest and most practical system to enable the study of molecular interactions experimentally and theoretically, which often exhibit features not available in monomers. , Various dimerization methods have been developed based on different driving forces including both non-covalent (hydrogen bonding, macrocyclic complexations, , host–guest interaction, halogen and chalcogen bonding, etc.) and covalent strategies. , According to the level of dynamics and the nature of linkages, most dimers can be assigned to three categories: (i) dynamic noncovalent dimers, (ii) pseudostatic noncovalent dimers, and (iii) static covalent dimers . These reported dimers have shown great applications in the fields of enhanced emission, , room-temperature phosphorescence, , supramolecular catalyst, , and near-infrared probes .…”

Mechanical Bond-Assisted Full-Spectrum Investigation of Radical Interactions

“…Noncovalent bonding interactions − lay the foundation for almost all the communications between molecules in chemical and biological systems, such as molecular recognition, − self-assembly, − signal transduction, , and catalysis. − Understanding these interactions not only can offer keys to mimicking , the structural and functional aspects of living systems, but also can enrich the toolkit for advanced noncovalent syntheses. − Whereas the dynamic nature of noncovalent bonding interactions is beneficial − for the construction of smart materials with responsiveness and adaptivity, a large proportion of these interactions are weak, labile, and sometimes transient, making it difficult to characterize and investigate them in depth. Particularly when it comes to complicated supramolecular systems involving multiple interactions, the contribution of weak interactions tends to be obscured by stronger ones.…”