Self-Assembly, Guest Capture, and NMR Spectroscopy of a Metal–Organic Cage in Water

Abstract

A green organic−inorganic laboratory experiment has been developed in which students prepare a selfassembling iron cage in D 2 O at room temperature. The tetrahedral cage captures a small, neutral molecule such as cyclohexane or tetrahydrofuran. 1 H NMR analysis distinguishes captured and free guests through diagnostic chemical shifts, splitting patterns, diffusion coefficients (using DOSY), and the appearance of captured hydrophobic molecules in D 2 O even when free guests are insoluble in water. Students are invited to test their hypotheses about guest binding and to perform control and competition experiments. All of the reagents are commercial, the 23-component self-assembly is complete in 1 week at room temperature (requiring neither workup nor purification), and the product solution is intensely purple. In their laboratory reports, students effectively related organic chemistry with molecular self-assembly, supramolecular chemistry, and host−guest interactions.

Integrating Photoactive Ligands into Dimension-Reduced Metal–Organic Frameworks: Harnessing the Power of Organic Photocatalysts

“…Notably, Nuclear Magnetic Resonance (NMR) becomes instrumental in this context. 1 H and 13 C NMR spectroscopy provide foundational structural insights. − Additionally, two-dimensional NMR techniques, including Correlation Spectroscopy (COSY), Nuclear Overhauser Effect Spectroscopy (NOESY), and Diffusion Ordered Spectroscopy (DOSY) are useful methods to elucidate proton couplings across multiple bonds and spatial dimensions, offering further substantiation of the cage structures. ,, 1 H COSY can reveal the structural information of the coordination cage by mapping the coupling of protons in structural fragments …”

Resorcin[4]arenes: A Convenient Scaffold To Study Supramolecular Self-Assembly and Host:Guest Interactions for the Undergraduate Curriculum

“…In addition, supramolecular chemistry bridges all of the traditional fields of chemistry as well as biochemistry, and is therefore a valuable tool to demonstrate to students the interdisciplinary nature of modern chemistry. Despite their potential to incorporate supramolecular chemistry into appropriate second-year undergraduate-level courses such as introductory analytical and organic chemistry, until recently most supramolecular experiments focused on advanced concepts in physical or inorganic chemistry, with few exercises geared toward lower-division organic courses . Given the value and importance of incorporating lessons on supramolecular chemistry into the undergraduate curriculum, more experiments are needed that are appropriate for lower-division students.…”

Reaction Scale and Green Chemistry: Microscale or Macroscale, Which Is Greener?

“…In both papers, the authors presented a large number of experiments on green chemistry implemented at the microscale, showing marked mutual benefits in several of them, and demonstrating the synergic connection between the two approaches to improve the benignity (meaning, for instance, less hazardous chemistry, less impact on the environment) of chemistry. Since then, several papers describing microscale synthesis experiments as green in the title or in the abstract/keywords have been published in this Journal . However, none of these papers includes a detailed analysis of the different fundamentals of microscale and green chemistry and their mutual connections, as well as metrics for evaluation of the microscale outcomes.…”