Thiophene, Selenophene, and Tellurophene-based Three-Dimensional Organic Frameworks

3D-Boronic Ester Architectures: Synthesis, Host-Guest Chemistry, Dynamic Behavior, and Supramolecular Catalysis

Boronic esters are known to be formed simply by mixing boronic acids and alcohols under neutral conditions, and the equilibrium is in favor of the boronic esters when 1,2- or 1,3-diols are employed as alcohols. By utilizing the dynamic nature of the boronic ester formation, our group successfully constructed unique boron-containing 3D structures, such as ring-shaped macrocycles, cages, and tubes, based on the boronic ester formation of various aromatic di-, tri-, or hexaboronic acids with an originally designed tetrol 1 containing two sets of fixed 1,2-diol units oriented on the same face of an indacene framework. Various functions of the obtained boronates were further pursued to disclose the characteristic features of this system. This personal account describes our self-assembled boronate system using tetrol 1 including synthesis, host-guest chemistry, kinetic connection, characteristic dynamic behaviors, and supramolecular catalysis.

Trends in Conjugated Chalcogenophenes: A Theoretical Study

Heavy atom substitution in chalcogenophenes is a versatile strategy for tailoring and ultimately improving conjugated polymer properties. While thiophene monomers are commonly implemented in polymer designs, relatively little is known regarding the molecular properties of the heavier chalcogenophenes. Herein, we use density functional theory (DFT) calculations to examine how group 16 heteroatoms, including the radioactive polonium, affect polychalcogenophene properties including bond length, chain twisting, aromaticity, and optical properties. Heavier chalcogenophenes are more quinoidal in character and consequently have reduced band gaps and larger degrees of planarity. We consider both the neutral and radical cationic species. Upon p-type doping, bond length rearrangement is indicative of a more delocalized electronic structure, which combined with optical calculations is consistent with the polaron-model of charge storage on conjugated polymer chains. A better understanding of the properties of these materials at their molecular levels will inevitably be useful in material design as the polymer community continues to explore more main group containing polymers to tackle issues in electronic devices.

The Synthesis and Optoelectronic Applications for Tellurophene-Based Small Molecules and Polymers

Tellurophene-based small molecules and polymers have received great attentions owing to their applications in thin-film transistors, solar cells, and sensors. This article reviews the current progress of the synthesis and applications of tellurophene-based small molecules and polymers. The physicochemical properties and optoelectronic applications of tellurophene-based materials are summarized and discussed. In the end, the challenges and outlook of tellurophene-based materials are presented.

Crystalline Anionic Germanate Covalent Organic Framework for High CO2 Selectivity and Fast Li Ion Conduction

The metalloid-centered covalent organic framework has attracted great interest from both its structure and application. Heavier elements have seldomly been incorporated in the covalent organic frameworks, even if they exhibit special structural features and properties. Herein, we reported the first crystalline germanate covalent organic framework with hexacoordinated germanate linked by an anthracene linker. The existence of counterion lithium ions in the framework provides a high CO₂ uptake of 88.5 cm³  g^-1 at 273 K and a high CO₂ /N₂ selectivity of 101. A significantly improved lithium ion conductivity of 0.25 mS cm^-1 at room temperature was observed due to the soft germanium center.