Synthesis, characterization and self-assembly of novel fluorescent alkoxy-substituted 1, 4-diarylated 1, 2, 3-triazoles organogelators

Synthesis and Self-assembly of Novel Nanofeather-like Fluorescent Alkyloxy-Containing Diphenyl Ether Organogelators

In this study, novel fluorescent low molecular-weight organogelators are derived from diphenyl ethers and substituted with para-alkoxy groups of different aliphatic chain lengths. The present research promotes the preparation of innovative nanofeather-like assemblies from the synthesized diphenyl ether-derived organogelators. The gelation performance of the prepared alkoxy-substituted diphenyl ethers was reported. The synthesis procedure was achieved by using a base-catalyzed reaction of hydroxyl-substituted diphenyl with various alcohols of different aliphatic chain lengths. The chemical structures of the synthesized diphenyl ether derivatives were studied by ¹H/¹³C NMR and infrared spectroscopy. Fluorescence and UV-vis absorption spectral analyses showed solvatochromism. The diphenyl ether derivatives with longer alkoxy terminal substituents showed enhanced thermoreversible gelation activity as compared to the diphenyl ether derivatives with shorter alkoxy terminal substituents. The morphological properties of the self-assembled diphenyl ethers were studied by transmission electron microscopy and scanning electron microscopy, which showed supramolecular architectures of highly ordered nanofeathers, enforced by van der Waals interactions and π-stacks. Depending on the length of the aliphatic tail, different morphologies were detected, including nanofeathers, nanofibers, and nanosheets. The antimicrobial and cytotoxic properties of the prepared diphenyl ether-derived organogelators were examined to confirm their possible use in various fields like drug delivery systems.

Methionine-Derived Organogels as Lubricant Additives Enhance the Continuity of the Oil Film through Dynamic Self-Healing Assembly

(S)-2-((1-(Hexadecylamino)-4-(methylthio)-1-oxobutan-2-yl)carbamoyl)benzoic acid (HMTA) was efficiently synthesized and successfully applied as an additive to several types of blank lubricant oils. Initially, HMTA self-assembles to fibrous structures and traps blank lubricant oils to form gel lubricants. The prepared gel lubricants show thermo-reversible properties and enhanced lubricating performance by 3∼5-fold. X-ray photoelectron spectrometry of the metal surface and the quartz crystal microbalance illustrated that there are no obvious interactions between HMTA and the metal surface. The results of Fourier transform infrared spectroscopy and X-ray diffraction further confirm that inter/intro-molecular H-bonding interactions are the main driving force for the self-healing of HMTA. Finally, molecular dynamics (MD) simulations show that the number of noncovalent H-bonding interactions fluctuates with time, and this highly dynamic H-bonding network could regulate the self-assembly process and result in the self-healing property of the HMTA organogel, which is consistent with the results of the step-strain tests. Especially, the Hirshfeld independent gradient model method at the quantum level demonstrated that C8/C9 aromatics of 500SN have strong π-π stacking interactions with the aromatic heads of HMTA and van der Waals interactions with the hydrophobic tails of HMTA, which disrupt the self-assembly behavior of the 500SN model. Therefore, the calculation studies offer a rational explanation for the superior lubricant property of the PAO10 gel as compared to that for 500SN.