To the article "Heterocyclic structures applied as efficient molecular probes for the investigation of chemically important interactions in the liquid phase'' by Heinz Langhals
The controlling of the internal interaction in multichromophores leads to functional dyes with novel properties. Such a controlling is demonstrated with perylene dyes and offers a manifold of novel ...possibilities.
Heterocyclic molecular probes were applied for the investigation chemically significant effects of the liquid phase to solute materials. A brief historic overview of the estimation of solvent effects ...is reported as well as most recent developments. The familiar three-dimensional concepts of solvent–solute interactions were upgraded to two-dimensional effects similar to surfaces where heterocyclic structures with compensating dipoles give basic insights in processes on the molecular level.
Cryo-milling of various plastic types into microplastic particles and detection via FLIM
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•FLIM measures fluorescence lifetime of plastics and thus can be used for identification and ...characterization of plastics•FLIM offers additional morphological information as well as information about the size and surface of plastics•Heat treatment causes changes in photon count and stable variations in fluorescence lifetime
The problem of micro- and nanoplastic (short: plastics) pollution is an increasing global issue and therefore several detection methods for plastics, also investigating the chemical nature via spectroscopy and chromatography, have been developed over the years. A new approach for identification and characterization of plastics is fluorescence lifetime imaging microscopy (FLIM) – a microspectroscopic method to detect fluorescence lifetime (τ) of plastics. We tested whether FLIM can be employed for the identification and characterization of plastics. Six types of plastics (ABS, PA6, PET, PLA, PPE, PU), with and without prior heat treatment, were subjected to FLIM with excitation wavelengths of 470 nm and 440 nm. The results provided mean τ (intensity weighted) values of 3.850 (+- 0.033) ns for ABS, 8.143 (+- 0.060) ns for PPE, 3.519 (+-0.090) ns for PET of a bottle from Germany and 3.564 (+-0.126) ns for PET of a bottle from the USA. The combination of mean intensity weighted τ and mean amplitude weighted τ values allowed for the significant differentiation of 52 (94.55 %) of the 55 possible plastic comparisons. Moreover, FLIM showed the potential for the sub-micrometer range plastic characterization, phasor analysis and allows for visual 3D-sectioning of samples that could be important for identification and characterization of plastics in tissue and environmental samples.
The electronics era is flourishing and morphing itself into Internet of Everything, IoE. At the same time, questions arise on the issue of electronic materials employed: especially their natural ...availability and low-cost fabrication, their functional stability in devices, and finally their desired biodegradation at the end of their life cycle. Hydrogen bonded pigments and natural dyes like indigo, anthraquinone and acridone are not only biodegradable and of bio-origin but also have functionality robustness and offer versatility in designing electronics and sensors components. With this Perspective, we intend to coalesce all the scattered reports on the above-mentioned classes of hydrogen bonded semiconductors, spanning across several disciplines and many active research groups. The article will comprise both published and unpublished results, on stability during aging, upon electrical, chemical and thermal stress, and will finish with an outlook section related to biological degradation and biological stability of selected hydrogen bonded molecules employed as semiconductors in organic electronic devices. We demonstrate that when the purity, the long-range order and the strength of chemical bonds, are considered, then the Hydrogen bonded organic semiconductors are the privileged class of materials having the potential to compete with inorganic semiconductors. As an experimental historical study of stability, we fabricated and characterized organic transistors from a material batch synthesized in 1932 and compared the results to a fresh material batch.
Perylenedicarboximides were interlinked in their free peri-position to form dyads where the UV/vis absorptivity was amplified by exciton effects and the strong fluorescence bathochromically shifted ...by molecular dynamics. Applications of this type of dye with such increased Stokes shifts were discussed.
The colorless naphthalene tetracarboxylic bisimides were laterally extended with imidazole rings to give colored and highly fluorescent materials. Donor-substituted phenyl groups at the imidazole ...rings cause further bathochromic shifts in fluorescence where the strong solvent influence in the spectra is typical for a TICT process. Applications are discussed.
Dyads of chromophores with orthogonal transition moments and sequences of aliphatic cage-structures as spacers were prepared where resonance energy transfer (FRET) proceeded in contrast to Förster’s ...theory even until 58 Å. The distance dependence of the efficiency was re-examined by means of various functions; the commonly used R –6 dependence gave acceptable results, but a slightly larger exponent was more useful for practical applications.
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