Fluorene-based click polymers: Relationship between molecular structure and nonlinear optical properties

Cholinesterase Inhibitory and Anti-Inflammatory Activity of the Naphtho- and Thienobenzo-Triazole Photoproducts: Experimental and Computational Study

New 1,2,3-triazolo(thieno)stilbenes were synthesized as mixtures of isomers and efficiently photochemically transformed to their corresponding substituted thienobenzo/naphtho-triazoles in high isolated yields. The resulting photoproducts were studied as acetyl- (AChE) and butyrylcholinesterase (BChE) inhibitors without or with interconnected inhibition potential of TNF-α cytokine production. The most promising anti-inflammatory activity was shown again by naphtho-triazoles, with a derivative featuring 4-pentenyl substituents exhibiting notable potential as a cholinesterase inhibitor. To identify interactions between ligands and the active site of cholinesterases, molecular docking was performed for the best potential inhibitors. Additionally, molecular dynamics simulations were employed to assess and validate the stability and flexibility of the protein-ligand complexes generated through docking.

Synthesis and photochemistry of novel 1,2,3-triazole di-heterostilbenes. An experimental and computational study

The synthesis, photoreactivity, and spectroscopic characterization of novel 1,2,3-triazole di-heterostilbenes bearing various aliphatic and aromatic substituents on the triazole rings were thoroughly explored. By introducing triazole rings into the o-divinylbenzene moiety, compared with the 2-furyl and 2-thienyl heteroanalogues, these compounds did not show any photochemical reactivity toward intramolecular cycloaddition reactions or electrocyclization processes. The research is further extended to the more in-depth examination of photochemical and photophysical characteristics of the investigated triazolo-stilbenes to explain the lack of reactivity in intramolecular photochemical cyclizations by configuration and substituent effects. Conformations of synthetically obtained novel triazoles are examined by Density Functional Theory (DFT). The time dependent-DFT approach was employed to obtain additional insight into the properties observed with UV/Vis spectroscopy. The frontier orbital energy was computationally investigated to determine the influence of cis-trans isomerism and the nature of substituents on the spectroscopic properties of the triazoles. Along with our previous studies of similar compounds containing furan and thiophene, respectively, this study shows that introducing various heteroaromatic rings induces diverse photochemistry and photophysics due to the conformational changes and change in electronic distribution within the molecular system.

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation

The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the function of optical power limiting. All known mechanisms of optical limiting have been analyzed and discussed for the different types of materials.