Optical and Electrochemical Properties of Anthraquinone Imine Based Dyes for Dye-Sensitized Solar Cells

Integrating Enzymes with Supramolecular Polymers for Recyclable Photobiocatalytic Catalysis

Chemical modifications of enzymes excel in the realm of enzyme engineering due to its directness, robustness, and efficiency; however, challenges persist in devising versatile and effective strategies. In this study, we introduce a supramolecular modification methodology that amalgamates a supramolecular polymer with Candida antarctica lipase B (CalB) to create supramolecular enzymes (SupEnzyme). This approach features the straightforward preparation of a supramolecular amphiphilic polymer (β-CD@SMA), which was subsequently conjugated to the enzyme, resulting in a SupEnzyme capable of self-assembly into supramolecular nanoparticles. The resulting SupEnzyme nanoparticles can form micron-scale supramolecular aggregates through supramolecular and electrostatic interactions with guest entities, thus enhancing catalyst recycling. Remarkably, these aggregates maintain 80 % activity after seven cycles, outperforming Novozym 435. Additionally, they can effectively initiate photobiocatalytic cascade reactions using guest photocatalysts. As a consequence, our SupEnzyme methodology exhibits noteworthy adaptability in enzyme modification, presenting a versatile platform for various polymer, enzyme, and biocompatible catalyst pairings, with potential applications in the fields of chemistry and biology.

Juglophen: a tetradentate non-innocent electron sponge naphthoquinone-imine ligand and its reduced and oxidized nickel complexes [Ni(jp)]-,0,+

The synthesis of new tetradentate dianionic N₂O₂ ligand juglophen (H₂jp, 1) and its nickel(II) complex [Ni(jp)] (2) is reported. The unprecedented ligand synthesis is accomplished via oxidative coupling of 1,5-dihydroxynapthalene and o-phenylenediamine by hypervalent phenyliodine(III)-diacetate. Ligand 1 and complex 2 were characterized via NMR, IR, UV-Vis spectroscopy, mass spectrometry, cyclic voltammetry and by XRD analysis. In order to investigate the non-innocent character of ligand 1, [Ni(jp)] (2) was oxidized using AgPF₆ to form [Ni(jp)]⁺ [PF₆]^- (3) whereas one-electron reduction with [Cp₂Co] generated [Cp₂Co]⁺[Ni(jp)]^- (4). The paramagnetic nature of the oxidized and reduced species 3 and 4 was validated via EPR spectroscopy and further investigated pursuing DFT calculations at the PBE-D3(BJ)/def2-TZVPP level of theory. Predominantly ligand-centered SOMOs of 3 and 4 are allowing insight towards a deeper understanding of the redox behavior of [Ni(jp)] (2).

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

This review surveys recent progress in the chemistry of polycyclic heteroaromatic molecules with a focus on structural diversity and synthetic methodology. The article covers literature published during the period of 2016-2020, providing an update to our first review of this topic (Chem. Rev. 2017, 117 (4), 3479-3716).

An Experimental and Theoretical Study of Dye Properties of Thiophenyl Derivatives of 2-Hydroxy-1,4-naphthoquinone (Lawsone)

A prospective study of the dye properties of non-toxic lawsone thiophenyl derivatives, obtained using a green synthetic methodology allowed for the description of their bathochromic shifts in comparison to those of lawsone, a well-known natural pigment used as a colorant that recently also has aroused interest in dye-sensitized solar cells (DSSCs). These compounds exhibited colors close to red, with absorption bands in visible and UV wavelength range. The colorimetric study showed that these compounds exhibited a darker color than that of lawsone within a range of colors depending on the substituent in the phenyl ring. Computational calculations employing Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT), showed that the derivatives have lower excitation energies than lawsone, while the alignment of their frontier orbitals regarding the conduction bands of TiO₂ and ZnO and the redox potential of the electrolyte I^-/I₃^- suggests that they could be employed as sensitizers. The study of the interactions of the lawsone and a derivative with a TiO₂ surface model by different anchoring modes, showed that the adsorption is thermodynamically favored. Natural bond orbital (NBO) analysis indicates a two-center bonding (BD) O-Ti as the main interaction of the dyes with TiO₂.

Design and synthesis of novel xanthone-triazole derivatives as potential antidiabetic agents: α-Glucosidase inhibition and glucose uptake promotion

Inhibiting the decomposition of carbohydrates into glucose or promoting glucose conversion is considered to be an effective treatment for type 2 diabetes. Herein, a series of novel xanthone-triazole derivatives were designed, synthesized, and their α-glucosidase inhibitory activities and glucose uptake in HepG2 cells were investigated. Most of the compounds showed better inhibitory activities than the parental compound a (1,3-dihydroxyxanthone, IC₅₀ = 160.8 μM) and 1-deoxynojirimycin (positive control, IC₅₀ = 59.5 μM) towards α-glucosidase. Compound 5e was the most potent inhibitor, with IC₅₀ value of 2.06 μM. The kinetics of enzyme inhibition showed that compounds 5e, 5g, 5h, 6c, 6d, 6g and 6h were noncompetitive inhibitors, and molecular docking results were consistent with the noncompetitive property that these compounds bind to allosteric sites away from the active site (Asp214, Glu276 and Asp349). On the other hand, the glucose uptake assays exhibited that compounds 5e, 6a, 6c and 7g displayed high activities in promoting the glucose uptake. The cytotoxicity assays showed that most compounds were low-toxic to human normal hepatocyte cell line (LO2). These novel xanthone triazole derivatives exhibited dual therapeutic effects of α-glucosidase inhibition and glucose uptake promotion, thus they could be use as antidiabetic agents for developing novel drugs against type 2 diabetes.

Influence of TiO₂ Nanoparticles on Liquid Crystalline, Structural and Electrochemical Properties of (8Z)-N-(4-((Z)-(4-pentylphenylimino)methyl)benzylidene)-4-pentylbenzenamine

Organic-inorganic hybrids based on liquid crystalline symmetrical imine (8Z)-N-(4-((Z)-(4-pentylphenylimino)methyl)benzylidene)-4-pentylbenzenamine (AZJ1) with two aliphatic chains and TiO₂ nanomaterials were obtained and investigated taking into account thr crystallographic form of titanium dioxide i.e., anatase versus rutile. The type of TiO₂ influences the mesomorphic properties of imine AZJ1, as observed by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) techniques. Fourier-Transform Infrared Spectroscopy (FT-IR) was used to investigate the interactions of oxygen vacancies located on the TiO₂ surface with the studied AZJ1 imine together with studying the influence of temperature. Both imine:TiO₂ anatase versus rutile hybrids possessed the highest occupied molecular orbital (HOMO) levels of about -5.39 eV (AZJ1:anatase) and -5.33 eV (AZJ1:rutile) and the lowest unoccupied molecular orbital (LUMO) levels of about -2.24 eV. The presence of TiO₂ in each hybrid did not strongly affect the redox properties of imine AZJ1. Organic devices with the configuration of ITO/TiO₂/AZJ1 (or AZJ1:TiO₂ anatase versus rutile)/Au were fabricated and investigated in the presence and absence of visible light irradiation with a light intensity of 93 mW/cm². Finally, to analyze defects in the constructed organic devices we used thermal imaging and atomic force microscopy (AFM). The addition of TiO₂ in both crystallographic forms has a positive influence on layer-forming properties that manifests itself as a very homogenous heat distribution for the whole sample.