Divalent Benzimidazolium-Based Axles for Self-Reporting Pseudorotaxanes.

Mono- and (bis)benzimidazoliums were evaluated both experimentally and computationally for their potential as pseudopolyrotaxane axle building blocks. Their aggregation and photophysical behavior, along with their potential to form a [2]pseudorotaxane with dibenzyl-24-crown-8, was studied through the synergistic application of 1D/2D and diffusion-ordered NMR spectroscopy, mass spectrometry, ultraviolet-visible and fluorescence spectroscopy, and time-dependent density functional theory. Their photophysical behavior was measured and modeled as a function of protonation state, solvent, and concentration.

Preparation and Characterization of a Small Library of Thermally-Labile End-Caps for Variable-Temperature Triggering of Self-Immolative Polymers.

The reaction between furans and maleimides has increasingly become a method of interest as its reversibility makes it a useful tool for applications ranging from self-healing materials, to self-immolative polymers, to hydrogels for cell culture and for the preparation of bone repair. However, most of these applications have relied on simple monosubstituted furans and simple maleimides and have not extensively evaluated the potential thermal variability inherent in the process that is achievable through simple substrate modification. A small library of cycloadducts suitable for the above applications was prepared, and the temperature dependence of the retro-Diels-Alder processes was determined through in situ H NMR analyses complemented by computational calculations.