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Herein, we report the coordination-driven self-assembly of a diazaporphyrin plate and a porphyrin prism, made using the same Ru-benzo molecular clip and 2:1 diruthenium acceptor to tetrapyridyl donor stoichiometry, and discuss characterization techniques used to distinguish the two. We describe how 1H NMR data can distinguish between plate and prism geometries based on peak shifts and splitting in the context of molecular symmetries. DOSY spectra show changes in hydrodynamic radius from the monomeric porphyrin to the prism (4.78 Å to 15.2 Å) and diazaporphyrin to plate (6.02 Å to 12.2 Å) consistent with the increase in size upon assembly. High resolution mass spectrometry provides further evidence for plate and prism, where specific peaks at diagnostic m/z values unequivocally establish the stoichiometry of assembly. Electronic absorption spectroscopy revealed a marked increase in molar absorptivity upon self-assembly. These results establish how molecular characterization techniques may be used to distinguish between possible self-assembly outcomes when a given building block may be encoded with directionality that is suitable for more than one geometry. 

Bis-iron(iii)-μ-oxo-porphyrin prisms may be tunedviapost-synthetic tethering. Tethered prisms show enhanced selectivity for the Oxygen Reduction Reaction (ORR) and maintain a cofacial geometry under homogeneous ORR conditions. 

Legacy and emerging per- and polyfluoroalkyl substances (PFAS) are widely detected in environmental and human samples because of their widespread use and resistance to degradation. Due to the increasing concern on health impacts of PFAS resulting from exposure to contaminated water, the development of novel materials to capture and remove PFAS from the environment is needed. Here, we present a self-assembling, fluorinated, zirconium-based metal–organic cage (F-ZrMOC) capable of capturing 37 different PFAS species, at an average of 82% removal from a solution that contains 400 ng/mL of each individual PFAS. The F-ZrMOC captured different classes of PFAS within 30 s, including perfluoroalkyl carboxylates, sulfonates, sulfonamides, ethoxylates, and fluorotelomer carboxylates/sulfonates/alcohols from water during in-vial, static, and flow through exposures (in which the F-ZrMOC is used as a solid phase extraction sorbent). Removal efficiency is higher for PFAS with chain lengths of seven carbons or higher; the presence of complex matrices such as untreated wastewater and groundwater samples did not significantly reduce the removal efficiencies for PFAS. The F-ZrMOC was characterized using 1H and 19F nuclear magnetic resonance (NMR) spectroscopy, and the stoichiometry of the synthesized cage was confirmed using Fourier transform-ion cyclotron resonance mass spectrometry. The surface area and pore size of F-ZrMOC were further determined by N2 and CO2 sorption measurements. 19F-NMR spectroscopy revealed that solvent plays an important role in the capture of PFAS; once the cages are in contact with methanol solution, captured PFAS are released.