We report on the experimental characterization of anisotropic supramolecular assemblies by infrared (IR) nanopolarimetry. The presented IR absorption anisotropy imaging method simultaneously provides nanoscale-resolved insights into internal composition, intermolecular interactions, and supramolecular orientation in a label-free and noninvasive fashion. Our study of porphyrin aggregates demonstrates that their morphology can be correlated with stable J-type and metastable H-type stacking-induced anisotropic organization, revealing different oriented attachment growth mechanisms supported by theory. This analysis establishes the broad applicability of IR nanopolarimetric studies to supramolecular polymerization and biomolecular assemblies, opening up new routes in polymer science and macromolecular research.
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http://dx.doi.org/10.1021/acsmacrolett.7b00147 | DOI Listing |
Molecules
December 2024
"C. D. Nenitzescu" Institute of Organic and Supramolecular Chemistry, Splaiul Independentei 202B, 060023 Bucharest, Romania.
Azulene-1,3-bis(semicarbazone), , and azulene-1,3-bis(thiosemicarbazone), , were synthesized by the acid-catalyzed condensation reactions of semicarbazide and thiosemicarbazide, respectively, with azulene-1,3-dicarboxaldehyde in stoichiometric amounts. Compounds and were identified by high-resolution mass spectrometry and characterized by IR, H-NMR, C-NMR, and UV-vis spectroscopic techniques. Crystal structure determination of azulene-1,3-bis(thiosemicarbazone) shows that the thiosemicarbazone units exhibit a -closed conformation, with both arms oriented in the same direction and adopting an configuration with respect to the imine linkages.
View Article and Find Full Text PDFNat Chem
January 2025
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.
Atomically precise nanoclusters can be assembled into ordered superlattices with unique electronic, magnetic, optical and catalytic properties. The co-crystallization of nanoclusters with functional organic molecules provides opportunities to access an even wider range of structures and properties, but can be challenging to control synthetically. Here we introduce a supramolecular approach to direct the assembly of atomically precise silver nanoclusters into a series of nanocluster‒organic ionic co-crystals with tunable structures and properties.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry, National Institute of Technology, Rourkela, Odisha 769008, India.
Bile salts (BS) are naturally occurring steroidal biosurfactants. The ease of functionalization of BSs has boosted their use as inexpensive building blocks for the fabrication of a broad set of value-added soft functional materials. In the present work, three fluorescent bile acid (FBA) derivatives have been synthesized by conjugating anthracene at the side chain of lithocholic acid, deoxycholic acid, and cholic acid to understand the effect of the nature of the steroid nucleus on their physicochemical properties.
View Article and Find Full Text PDFChemistry
December 2024
Sapienza Università di Roma, Chemistry, Piazzale Aldo Moro 5, Dipartimento di Chimica, edificio CU 014, 00185, Rome, ITALY.
The outstanding efficiency and selectivity of enzymatic reactions, such as C-H oxidation by nonheme iron oxygenases, stems from a precise control of substrate positioning inside the active site. The resulting proximity between a specific moiety (a certain C-H bond) to the reactant (a FeIV(O) active species) translates into higher rates and selectivity, that can be in part replicated also with artificial supramolecular catalysts. However, structural modification of the position and orientation of the binding site both in enzymes and in artificial catalysts often leads to significant variations in reactivity that can be difficult to rationalize due to the system's complexity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
College of Chemistry and Chemical Engineering, Luoyang Normal University, Henan Province Function-Oriented Porous Materials Key Laboratory, Luoyang, 471934, P. R. China.
The synthesis of high-ordered mechanically interlocked supramolecular structures is an extremely challenging topic. Only two linear [4]catenanes have been reported so far and there is no defined strategy to obtain cyclic [4]catenane. Herein, two unprecedented cyclic [4]catenanes, 1 and 2, were prepared in high yields.
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