Supramolecular self-assembly offers a feasible route for nanopatterning and functionality. The construction and precise control of selective adsorption at the molecular scale play essential roles in fundamental sciences and practical applications. Molecular tiling such as trihexagonal tiling Kagome networks has potential promising chemical and physical properties. Distorted Kagome-like networks controllable fabrication is possible by coupling molecular functional groups and substrate atoms. A chiral Kagome-like network was constructed using IFDO ([1,2-b]fluorene-6,12-dione) as precursor molecules complemented with molecular beam epitaxy and annealing strategies. Revealing arrangements of the assembled network of O-Cu metal coordination linked Kagome-like networks on the Cu(1 1 1) surface and their assembly mechanisms and cavity characteristics were explored in detail through scanning tunneling microscopy combined with density functional theory. Based on the electronic state difference between the hole center of the network and the molecular backbone, the host–guest network was successfully prepared by co-depositing C 60 molecules. Kagome-like networks could as an efficient template for regulating the adsorption configuration of C 60 . Our results demonstrate a controllable and efficient method to design atomically precise ordered host–guest assemblies on solid surfaces, advancing the approach is yet another step toward the fabrication of molecular devices.
Ni Cheng,Xiaoyuan Ma,Xiang Sheng,Tao Wang,Rui Wang,Jingjing Jiao,Li Yu
Two structurally similar imidazolium-based anionic surface active ionic liquids (SAILs) with double hydrocarbon chains, viz. 1-butyl-3-methylimidazolium bis(2-ethylhexyl) sulfosuccinate (C 4 mim-AOT) and 1-butyl-3-methylimidazolium bis(2-ethylhexyl) phosphate (C 4 mim-DEHP), were synthesized by a straightforward ion-exchange technique. A comparative investigation of their aggregation behavior with the corresponding traditional anionic surfactants, sodium bis(2-ethylhexyl) sulfosuccinate (Na-AOT) and sodium bis(2-ethylhexyl) phosphate (Na-DEHP) in aqueous solution was performed in detail by surface tension, electric conductivity, fluorescence spectra and dynamic light scattering measurements. The critical micelle concentration (CMC) values for the surfactants with double hydrocarbon chains obtained by different techniques are in good agreement. The surface activity of C 4 mim-AOT and C 4 mim-DEHP is superior to that of the corresponding traditional anionic surfactants, Na-AOT and Na-DEHP. It is also found that for anionic SAILs the nature of the anionic active group is a dominant factor in the determination of their aggregation behavior in aqueous solution, e.g. CMC and aggregation number, while the introduced organic cation plays a minor role. Theoretical calculations show that more conformations and electronegativity for DEHP anion leads to higher aggregation number and CMC values for C 4 mim-DEHP. This work is expected to be of practical values for the environmental friendly anion SAILs in nanomaterial synthesis and phase separation, etc.
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