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21 pages, 5779 KiB

Open AccessArticle

Photochemical Transformations of Diverse Biologically Active Resveratrol Analogs in Batch and Flow Reactors

by Milena Mlakić, Hana Perinić, Vitomir Vušak, Ottó Horváth, Diego Sampedro, Raúl Losantos, Ilijana Odak and Irena Škorić

Molecules 2024, 29(1), 201; https://doi.org/10.3390/molecules29010201 - 29 Dec 2023

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Abstract

Previous biological tests have shown that some resveratrol analogs exhibited significant antioxidative and cholinesterase inhibitory potential, as evidenced by lower IC₅₀ values compared to the established standards, resveratrol and galantamine, respectively. Photochemical transformations were made in parallel on these compounds in the [...] Read more.

Previous biological tests have shown that some resveratrol analogs exhibited significant antioxidative and cholinesterase inhibitory potential, as evidenced by lower IC₅₀ values compared to the established standards, resveratrol and galantamine, respectively. Photochemical transformations were made in parallel on these compounds in the presence of porphyrin photocatalysts in batch and microreactor, showing the significant advantage of flow photochemistry concerning productivity, selectivity, and yields. In this research, the products of photocatalysis and direct irradiation (photolysis) of resveratrol analogs were compared to elucidate how the types and ratios of the products depend on the excitation energy, to reveal the effects of the substituent on the photoinduced reactions and to rationalize experimentally and computationally the nature and ratio of the obtained products. Thus, two main paths were computed in agreement with the experimental results: isomerization with the participation of triplet state intermediates to yield the experimentally detected cis-isomers and subsequent cyclization following a pathway not available for the trans-isomers. The investigation of five model compounds confirmed the advantages of the flow photoreactor in the photochemical reactions of heterocyclic resveratrol analogs. Full article

(This article belongs to the Special Issue Chemical Research on Photosensitive Materials)

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11 pages, 2655 KiB

Open AccessArticle

Bio-Inspired Hydrogel–Elastomer Actuator with Bidirectional Bending and Dynamic Structural Color

by Yongqing Xia, Yaru Meng, Ronghua Yu, Ziqi Teng, Jie Zhou and Shengjie Wang

Molecules 2023, 28(19), 6752; https://doi.org/10.3390/molecules28196752 - 22 Sep 2023

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Abstract

In nature, some creatures can change their body shapes and surface colors simultaneously to respond to the external environments, which greatly inspired researchers in the development of color-tunable soft actuators. In this work, we present a facile method to prepare a smart hydrogel [...] Read more.

In nature, some creatures can change their body shapes and surface colors simultaneously to respond to the external environments, which greatly inspired researchers in the development of color-tunable soft actuators. In this work, we present a facile method to prepare a smart hydrogel actuator that can bend bidirectionally and change color simultaneously, just like an octopus. The actuator is fabricated by elastomer/hydrogel bilayer and the hydrogel layer was decorated with thermoresponsive microgels as the photonic crystal blocks. Compared with the previously reported poly(N-isopropylacrylamide) hydrogel-based bilayer hydrogel actuators, which are generally limited to one-directional deformation, the elastomer/hydrogel bilayer actuator prepared in our work exhibits unique bidirectional bending behavior in accordance with the change of structural color. The bending degrees can be changed from −360° to 270° in response to solution temperatures ranging from 20 °C to 60 °C. At the same time, the surface color changes from red to green, and then to blue, covering the full visible light spectrum. The bending direction and degree of the hydrogel actuator can easily be adjusted by tuning the layer thickness ratio of the elastomer/hydrogel or the composition of the hydrogel. The color-tunable hydrogel-elastomer actuator reported in this work can achieve both programmable deformations and color-changing highly resembling the natural actuating behaviors of creatures. Full article

(This article belongs to the Special Issue Chemical Research on Photosensitive Materials)

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14 pages, 5809 KiB

Open AccessArticle

In Situ Construction of Near-Infrared Response Hybrid Up-Conversion Photocatalyst for Degrading Organic Dyes and Antibiotics

by Lianqing Yu, Yankun Wang, Xinhai Su, Chong Liu, Kehui Xue, Huihua Luo, Yaping Zhang and Haifeng Zhu

Molecules 2023, 28(18), 6674; https://doi.org/10.3390/molecules28186674 - 18 Sep 2023

Viewed by 655

Abstract

Unique nonlinear optical properties for converting low-energy incident light into high-energy radiation enable up-conversion materials to be employed in photocatalytic systems. An efficient near-infrared (NIR) response photocatalyst was successfully fabricated through a facile two-step method to load BiOBr on the Nd³⁺, [...] Read more.

Unique nonlinear optical properties for converting low-energy incident light into high-energy radiation enable up-conversion materials to be employed in photocatalytic systems. An efficient near-infrared (NIR) response photocatalyst was successfully fabricated through a facile two-step method to load BiOBr on the Nd³⁺, Er³⁺@NaYF₄ (NE@NYF) up-conversion material. The NE@NYF can transform NIR into visible and UV light and promote charge–energy transfer in the semiconductor. Consequently, the as-obtained photocatalysts exhibit excellent photodegradation performance for rhodamine B dye (RhB) and tetracycline (TC) organic pollutants. About 98.9% of the RhB was decomposed within 60 min with the 20% NE@NYF-B sample, outperforming the pristine BiOBr (61.9%). In addition, the 20% NE@NYF-B composite could decompose approximately 72.7% of the organic carbon during a 10 h reaction, which was almost two-fold more than that of BiOBr. Meanwhile, a possible charge transfer mechanism is proposed based on the recombination of electron–hole pairs and reactive oxygen species. This work provides a rational hybrid structure photocatalyst for improving photocatalytic performance in the broadband spectrum and provides a new strategy for NIR light utilization. Full article

(This article belongs to the Special Issue Chemical Research on Photosensitive Materials)

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