Synthesis and characterization of two 3-D polymeric lanthanide complexes constructed from 1,2,4,5-benzenetetracarboxylic acid

Supramolecular metallogels constructed from carboxylate gelators

Serendipity still plays a role in gel discovery as the prediction of gel formation is difficult. This work explores the role of ligand, metal salt, solvent, and temperature in the formation of a low molecular mass carboxylate iron(iii) system. The influence of each component is discussed. The gels obtained were characterised using thermal analysis, Fourier transform-infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, elemental analysis, microwave plasma-atomic emission spectroscopy, and inductively coupled plasma optical emission spectrometry. The response to external stimuli, including dye and gas sorption was examined.

Enhanced Lithium Storage Capacity of a Tetralithium 1,2,4,5-Benzenetetracarboxylate (Li4C10H2O8) Salt Through Crystal Structure Transformation

Because of their low price, design flexibility, and sustainability, organic-based electrode materials are considered one of the most promising next-generation alternatives to inorganic materials in Li-ion batteries. However, a clear understanding of the changes in the molecular crystal structure during Li-ion insertion/extraction and its relationship to excess capacity (over theoretical capacity) is still lacking. Herein, the tetralithium 1,2,4,5-benzenetetracarboxylate (Li₄C₁₀H₂O₈, Li₄BTC) salt was prepared using a simple ion-exchange reaction at room temperature and under solvothermal conditions (100 °C). The solvothermally synthesized salt (Li₄BTC-S) exhibited a well-ordered nanosheet morphology, whereas the room-temperature salt (Li₄BTC-R) was comprised of irregularly shaped particles. During the cycling of Li₄BTC-S, molecular rearrangement occurred to reduce the stress caused by repeated Li-ion insertion/extraction, resulting in a change in the crystal structure from triclinic to monoclinic and an increased free volume. This contributed to an increase in the reversible capacity to 1016 mAh g^-1 during the initial 25 cycles at 0.1 A g^-1, and finally the capacity stabilized at ca. 600 mAh g^-1 after 100 cycles, which is much higher than its theoretical capacity (234 mAh g^-1). Compared with Li₄BTC-R, Li₄BTC-S delivered a higher reversible capacity of 190 mAh g^-1 at a high current density of 2 A g^-1, with an excellent long-term cyclability of up to 1000 cycles, which was attributed to the straight free volume columns and the low-charge-transfer limitation.

A series of divalent metal coordination polymers based on isomeric tetracarboxylic acids: synthesis, structures and magnetic properties

A series of M(ii) coordination polymers has been synthesized. 1–3 contain 1D infinite chains, and these 1D chains are further linked by hydrogen bonding to form 3D supramolecular networks. While 4 and 5 show tetra- or penta-nodal 3D network, respectively.