A single-electron tetrel bond was predicted and characterized in FXH₃⋯CH₃ (X = C, Si, Ge, and Sn) complexes.

A novel hierarchical multicarbonyl polyimide derivative was synthesized by facile condensation polymerization of 3,3′,4,4′-diphenylketotetraanhydride and 2,6-diaminoanthraquinone, which benefits from various carbonyl groups and benzene rings in each monomer. The designed chemical composition and careful regulation of polymerization conditions endow it with an unprecedented superstructure with spherulite-like architectures constructed by highly compact arrangement of packed 2D nanosheets, which is favorable to trigger interfacial energy storage and contribute to a large storage capacity. When explored as an anode material for lithium-ion batteries, the polyimide derivative could deliver a reversible capacity of 1343.8 mA h g⁻¹ at 100 mA g⁻¹, a good rate capability of 208.9 mA h g⁻¹ at 1.5 A g⁻¹ and an excellent cycling performance of 665.1 mA h g⁻¹ at 250 mA g⁻¹ after 50 cycles. Aided by theoretical calculations and probing of electrochemical behaviors, a rational prediction for the complex lithium-ion storage mechanism is proposed. Furthermore, the obtained polymeric electrode also demonstrates good sodium-storage activity with a high capacity of 275.8 mA h g⁻¹ at 25 mA g⁻¹ and a good cycling stability of 130 mA h g⁻¹ at 50 mA g⁻¹ for 100 cycles, demonstrating its broader applications as appealing anode materials for next-generation high-energy batteries.

The complexes of XH₃F$\mathrm{\cdots }{{\text{N}}_3}^{-}$ /OCN⁻/SCN⁻ (X = C, Si, Ge, and Sn) have been investigated at the MP2/aug-cc-pVTZ(PP) level. The σ-hole of X atom in XH₃F acts as a Lewis acid forming a tetrel bond with pseudohalide anions. Interaction energies of these complexes vary from −8 to −50 kcal/mol, mainly depending on the nature of X and pseudohalide anions. Charge transfer from N/O/S lone pair to X–F and X–H ${\sigma }^{*}$ orbitals results in the stabilization of these complexes, and the former orbital interaction is responsible for the large elongation of X–F bond length and the remarkable red shift of its stretch vibration. The tetrel bond in the complexes of XH₃F (X = Si, Ge, and Sn) exhibits a significant degree of covalency with XH₃F distorted significantly in these complexes. A breakdown of the individual forces involved attributes the stability of the interaction to mainly electrostatic energy, with a relatively large contribution from polarization. The transition state structures that connect the two minima for CH₃Br$\mathrm{\cdots }{{\text{N}}_3}^{-}$ complex have been localized and characterized. The energetic, geometrical, and topological parameters of the complexes were analyzed in the different stages of the S_N2 reaction ${{\text{N}}_3}^{-}$ + CH₃Br → Br⁻ + CH₃N₃.

Fluorophores coupled with supramolecules lead to “dot” topologies in citric-acid derived carbon dots under the effect of hydrogen bonding.

Optically transparent polyimide (PI) films with high-temperature resistance have been considered as promising flexible substrate materials for next-generation micro-electronics fields. However, the trade-off between high optical transparency and a low coefficient of linear thermal expansion (CTE) in one material is the key issue to realize their applications. In this work, an effective design to solve the problem is presented by introducing rigid-rod amide units in colorless and transparent PI chains to regulate intra- and interchain interactions. Based on this concept, two types of highly transparent poly(amide-imide) (PAI) films with low CTE were synthesized derived from 3,5-diaminobenzotrifluoride (m-TFPDA) and novel diacids containing imide rings 2,2′-(5-(trifluoromethyl)-1,3-phenylene)bis(1,3-dioxoisoindoline-5-carboxylic acid) (DAc-1) and 2,2′-(2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diyl)bis(1,3-dioxoisoindoline-5-carboxylic acid) (DAc-2), respectively. The obtained PAI films (approximately 30 μm) achieved high optical transparency (λ_cutoff = 380 nm, T_{450 nm} = 81%, haze = 0.80), light color (L* = 95.42, a* = −1.45, b* = 5.04, yellow index = 7.23), and low CTE = 15 parts per million per °C. The PAI films also exhibited satisfactory thermal stability with a glass transition temperature (T_gs) at approximately 320 °C and 5 wt% decomposition temperature (T_d 5%) above 450 °C under an N₂ atmosphere. The tensile strength and modulus exceeded 100 MPa and 2.50 GPa, respectively. The intrinsic dielectric constant (k) and dielectric loss values are approximately 2.60 and 0.02 at 10 kHz, respectively, and a stable low-dielectric performance was observed up to 280 °C. This design strategy successfully lowers the CTE and maintains high optical transparency of PI films due to the rigid-rod amide unit increasing the rigidity of the molecular backbones, enhancing the orientation of in-plane polymer chains, and controlling the charge transfer complex (CTC) effects, which was proved by aggregation structure analysis and simulated calculations. This design strategy can also be used in other structures to prepare highly transparent PI films with low CTE for flexible micro-electronics fields.