Synthesis, Characterization, and Self-Assembly of a Tetrathiafulvalene (TTF)–Triglycyl Derivative

Abstract

In this work, we describe the synthesis, characterization, and self-assembly properties of a new tetrathiafulvalene (TTF)-triglycyl low-molecular-weight (LMW) gelator. Supramolecular organogels were obtained in various solvents via a heating-cooling cycle. Critical gelation concentrations (CGC) (range ≈ 5-50 g/L) and thermal gel-to-sol transition temperatures (T gel) (range ≈ 36-51 • C) were determined for each gel. Fourier transform infrared (FT-IR) spectroscopy suggested that the gelator is also aggregated in its solid state via a similar hydrogen-bonding pattern. The fibrillar microstructure and viscoelastic properties of selected gels were demonstrated by means of field-emission electron microscopy (FE-SEM) and rheological measurements. As expected, exposure of a model xerogel to I 2 vapor caused the oxidation of the TTF unit as confirmed by UV-vis-NIR analysis. However, FT-IR spectroscopy showed that the oxidation was accompanied with concurrent alteration of the hydrogen-bonded network.

Conformation-Dependent Monolayer and Bilayer Structures of an Alkylated TTF Derivative Revealed using STM and Molecular Modeling

“…Figure a shows an apparent concentration dependence of the normalized UV–vis spectra of 1 , which even at the lowest concentration differ from those of dilute solutions of alkyl- or thioalkyl-substituted TTF derivatives in several solvents. − However, the normalized spectra recorded for the same concentration range at 65 °C are identical over the concentration range used (Figure b). Their features, consisting of a maximum at 307 nm, a shoulder at 329 and 380 nm, and a long wavelength tail extending to 500 nm, match those of tetrathioalkyl substituted TTF derivatives in dilute solution, as well as calculated spectra of tetramethylbis­(ethylenedithio)­tetrathiafulvalene. − Long wavelength tails, extending sometimes to 1400 nm, were reported for thin layer TTF derivatives. − For UV–vis spectra obtained at higher temperatures (Figure b), the short wavelength maximum and shoulder become more prominent, while at longer wavelengths the transmittance (above 350 nm) is increased systematically, and the weak bands at 374 and 446 nm disappear in favor of the 380 nm species. The maximum at 307 nm and the shoulder at 329 nm are characteristic for monomers as upon aggregation these transitions shift to 297 and 317 nm, respectively .…”

“…Another plausible explanation is the formation of the TTF° + radical cation since TTF and its derivatives are easily oxidized. The absorption bands of the radical cation of TTF and thio-alkyl substituted TTFs are situated at 430 nm, 495 nm, 580 nm and between 750 and 850 nm, respectively, which could explain the increased absorption at wavelengths longer than 400 nm. ,,− However, the reversible nature of the temperature dependence would indicate that the TTF° + radical cation is reduced back to TTF which is improbable in the absence of a reducing agent.…”

Engineering a Two‐Component Hemostat for the Treatment of Internal Bleeding through Wound‐Targeted Crosslinking

“…As wound‐targeting nanoparticles were observed in several studies to result in significantly higher accumulation at the wound site, [ 9b,17,18 ] the aim of the two‐component system was to leverage this phenomenon and promote significant crosslinking selectively at higher concentrations. The formation of a gel occurs only when polymer concentrations exceed the critical gelation concentration (CGC), [ 19 ] which has been reported at concentrations of 130 mg mL −1 for PEG‐PLGA [ 20 ] and 260 mg mL −1 for PEG‐PLA gels. [ 21 ] Representative inversion tests of the nanoparticle solutions at 150 mg mL −1 at 1:1 stoichiometry have been provided in Figure S4 (Supporting Information), confirming gelation within this range.…”

Organogels Fabricated from Self-Assembled Nanotubes Containing Core Substituted Perylene Diimide Derivative

“…The formation of these organogels was confirmed by the “vial inversion test” (Figure S9). , The gelation ability of PDI-1 in different solvents is summarized in Table .…”