Monthly Archives: March 2024

Nonperipherally and peripherally substituted water‐soluble magnesium (II) phthalocyanines and their DNA binding, nuclease activities

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Nonperipherally and peripherally substituted water-soluble magnesium (II) phthalocyanines and their DNA binding, nuclease activities

We have synthesized magnesium (II) phthalocyanines (2a, 3a) and their water-soluble derivatives (2b, 3b). The ct-DNA binding and supercoiled plasmid DNA nuclease properties of the water-soluble compounds were investigated using different methods. All of these results showed that 2b had promising potential as a photosensitizer agent for photodynamic therapy.


In this study, magnesium (II) phthalocyanines (2a, 3a) and their water-soluble derivatives (2b, 3b) were synthesized via multistep reactions. The structures of these phthalocyanines were identified by FT-IR, NMR, MALDI-TOF, and UV–Vis spectroscopy. The ct-DNA binding (UV–Vis absorption, competitive EB binding, and agarose electrophoresis studies) and supercoiled plasmid DNA nuclease properties (hydrolytic, photonuclease, oxidative nuclease, and photooxidative nuclease) of the water-soluble compounds were investigated using different methods. The DNA binding constant (K b ) values of 2b and 3b were calculated as 8.45 ± (0.25) × 104 and 7.71 ± (0.13) × 104 M−1 at 25°C, respectively. The results showed that 2b had a stronger ct-DNA binding effect than 3b according to K b and r values. The DNA nuclease studies claimed that both compounds indicated photonuclease activity on plasmid DNA depending on the light dose. Additionally, 2b had a higher photonuclease capacity than 3b. All of these results showed that 2b had promising potential as a photosensitizer agent for photodynamic therapy.

Water‐Doped Brønsted Acidic Protic Ionic Liquids for Enhanced Tributyl Citrate Synthesis in a Two‐Phase Esterification System

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Tributyl citrate (TBC) plays a crucial role as a plasticizer, enhancing the flexibility of polymers like polyvinyl chloride. Its biodegradability and non-toxic nature contribute to its eco-friendly appeal, making it a preferred additive in diverse industries, including food packaging, medical devices, toys, and consumer goods. Herein, a method for the synthesis of TBC using inexpensive Brønsted acidic protic ionic liquids (ILs) in a two-phase reaction system is presented. The esterification process is carried out with high yield (>99%), selectivity (up to 98%) and short reaction time of 2h. The catalyst in the form of IL shows excellent performance and stability, desirable for industrial applications.

Bifunctional Sildenafil Diazeniumdiolates Acting as Phosphodiesterase 5 Inhibitors and Nitric Oxide Donors ̶ Towards Wound Healing

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Inefficient wound healing poses a global health challenge with a lack of efficient treatments. Wound healing issues often correlate with low endogenous nitric oxide (NO) levels. While exogenous delivery with NO-releasing compounds represents a promising therapeutic strategy, controlling the release of the highly reactive NO remains challenging. Phosphodiesterase 5 (PDE5) inhibitors, like sildenafil, have also been shown to promote wound healing. This study explores hybrid compounds, combining NO-releasing diazeniumdiolates with a sildenafil-derived PDE5 inhibitor. One compound demonstrated a favorable NO-release profile, triggered by an esterase (prodrug), and displayed in vitro nanomolar inhibition potency against PDE5 and thrombin-induced platelet aggregation. Both factors are known to promote blood flow and oxygenation. Thus, our findings unveil promising prospects for effective wound healing treatments.

Unraveling Ferroptosis Mechanisms: Tracking Cellular Viscosity with Small Molecular Fluorescent Probes

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Ferroptosis is a recently identified form of regulated cell death characterized by iron accumulation and lipid peroxidation. Numerous functions for ferroptosis have been identified in physiological as well as pathological processes, most notably in the treatment of cancer. The intricate balance of redox homeostasis is profoundly altered during ferroptosis, leading to alteration in cellular microenvironment. One such microenvironment is viscosity among others such as pH, polarity, and temperature. Therefore, understanding the dynamics of ferroptosis associated viscosity levels within organelles is crucial. To date, there are a very few reviews that detects ferroptosis assessing reactive species. In this review, we have summarized organelle’s specific fluorescent probes that detects dynamics of microviscosity during ferroptosis. Also, we offer the readers an insight of their design strategy, photophysics and associated bioimaging concluding with the future perspective and challenges in the related field.

Hollow nitrogen‐doped carbon spheres as zincophilic sites for Zn flow battery

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Severe dendrite growth on Zn anodes poses a significant challenge to the development of Zn-based batteries. An effective strategy for inhibiting the formation of Zn dendrites involves electrode modification. In this study, hollow nitrogen-doped carbon spheres (HNCS) are synthesized and used as electrodes to regulate Zn deposition in Zn-based flow batteries. The electrochemical performance of HNCS reveals that the pyrrole nitrogen of HNCS changes the electrode surface state. Therefore, HNCS can inhibit the hydrogen evolution reaction and achieve uniform Zn deposition. HNCS can effectively inhibit dendrite growth and improve the reversibility of the Zn plating/stripping process to regulate the reversibility of Zn-based batteries. The zinc–bromine redox flow battery assembled with HNCS significantly reduces the hydrogen evolution reaction and exhibits a coulombic efficiency of 90% and energy efficiency of 73% at a current density of 60 mA cm–2. Similarly, an alkaline zinc–iron flow battery can maintain high Coulombic efficiency and energy efficiency of 83%.

Photoinduced [2+2] and [4+4] Cycloaddition and Cycloreversion Reactions for the Development of Photocontrollable DNA Binders

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Photoinduced [2+2] and [4+4] Cycloaddition and Cycloreversion Reactions for the Development of Photocontrollable DNA Binders

In this Concept Article the scope, the limits, and the potential of the photoinduced [2+2] and [4+4] cycloaddition–cycloreversion sequence in the development of photoswitchable DNA binders are presented.


Abstract

In the current field of photopharmacology, molecular photoswitches are applied whose interactions with DNA can be triggered or controlled by light. And although several photochromic reactions have been shown to serve this purpose well, the reversible photocycloaddition and photocycloreversion reactions have been largely neglected. This absence of research is surprising because especially the photodimerization of a DNA ligand leads to products with significant change of the size and shape which, in turn, leads to strongly diminished or even suppressed DNA association. Therefore, photocycloaddition–cycloreversion sequences have a huge potential for the photoinduced, reversible deactivation and activation of ligand–DNA interactions, as will be shown with selected examples in this Concept Article. Specifically, heterostyryl and -stilbene derivatives are presented whose DNA–binding properties are efficiently switched in reversible [2+2] photocycloaddition reactions. In addition, the photocontrolled DNA–binding of anthracene derivatives and their heterocyclic benzo[b]quinolizinium analogues in a [4+4] photocycloaddition, as well as the use of this reaction as part of dual–mode switches in combination with redox-active functionalities, are highlighted. Furthermore, examples of conjugates are provided, in which the photochromic unit is bound covalently to nucleic acids or proteins, such that the photocycloaddition reaction can be used for reversible photoinduced crosslinking, ligation, or inhibition of gene expression.

Triplet Excited State Mechanistic Study of meso‐Substituted Methylthio Bodipy Derivative: Time‐Resolved Optical and Electron Paramagnetic Resonance Spectral Studies

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Understanding the intersystem crossing (ISC) mechanism of organic compounds is essential for designing new triplet photosensitizers. We investigated the ISC mechanism of a heavy atom-free Bodipy derivative with thiomethyl substitution (S-BDP). A long-lived triplet state was observed with nanosecond transient absorption spectroscopy with lifetime of 7.5 ms in a polymer film and 178 ms in fluid solution, longer as compared with what was previously reported . Femtosecond transient absorption studies retrieved an ISC time constant of ~3 ns. Time-resolved electron paramagnetic resonance (TREPR) indicated a special triplet electron spin polarization phase (ESP) pattern (a, e, a, e, a, e), different from the typical ESP (e, e, e, a, a, a)  for the spin-orbit coupling mechanism. This indicates that the electron spin selectivity of the ISC of S-BDP is different from  the normal SOC effect in iodo-Bodipy. Simulations of the TREPR spectra give a zero-field-splitting D parameter of -2257 MHz, much smaller as compared to the reference 2,6-diiodo-Bodipy (D = -4380 MHz). The computed SOC matrix elements (0.28-1.59 cm-1) and energy gaps for the S1/Tn states suggest that the energy matching between the S1 and T2/T3 states (supported by the largest kISC ~109 s-1) enhances the ISC for this compound.

Multifunctional Logic Operations Based Upon Congruent ion Sensing Appended with a Strategic Molecular Device: Spectroscopic Approach

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A multi-responsive smart molecular system was constructed on a newly synthesized Salen molecule, 1,3-bis((E)-2,3,4-trimethoxy benzylideneamino) propan-2-ol (TMBP) to selectively validate the presence as well as the absence of Cu2+ dictated by another selective metal ion, Zn2+. The emission efficiency of the non-emissive probe was significantly enhanced by Zn2+ selectively, while specific binding of the probe-Zn2+ complex with Cu2+ completely quenched the enhanced emission. Thus, the probe acted as a reporter molecule for the selective detection of Cu2+ in the co-presence of Zn2+. Comprehensive spectroscopic studies indicated that Zn2+ ion-coordination significantly reduced the flexibility of the Schiff base unit and decreased the extent of photoinduced electron transfer (PET) enabling an enhancement of fluorescence intensity. While, Cu2+, a d9 system, induced paramagnetic quenching through formation of a stable ground-state complex as established from the UV-Vis analysis and time resolved fluorescence measurements. The spectroscopic results were implemented into the designing of a multifunctional molecular logic system that could function as YES, NOT, INHIBIT, PASS 0, TRANSFER and NOT TRANSFER logic gates. Finally, a blueprint of a smart molecular device was proposed to present the relay sensing of Zn2+ and Cu2+ through logical outputs that would work in-sync with the spectroscopic results.

Effect of Co‐Surfactants on Properties and Bactericidal Activity of Cu2O and Hybrid Cu2O/Ag Particles

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Effect of Co-Surfactants on Properties and Bactericidal Activity of Cu2O and Hybrid Cu2O/Ag Particles

This study focuses on a green synthesis of Cu2O and Cu2O−Ag particles using ascorbic acid (LAA) as a reducing agent in the presence of two surfactants, polyethylene glycol 6000 and sodium dodecyl sulfate. The hybrid materials exhibit strongly antibacterial activity and are potential for the application in the acrylic emulsion coating.


Abstract

Nanomaterials based on metal oxides, especially Cu2O, have received much attention in recent years due to the many unique properties of the surface plasmon resonance they provide. The report presented the co-precipitation method, a simple preparation method to produce Cu2O oxide particles. In addition, to improve the unique antibacterial properties of Cu2O, a proposed method is to attach Ag nanoparticles to the surface of Cu2O particles. The Cu2O and Cu2O−Ag particles were synthesized based on redox reactions using ascorbic acid (LAA) as a reducing agent. Moreover, in this experiment, two surfactants, polyethylene glycol 6000 (PEG 6000) and sodium dodecyl sulfate (SDS), were added during the manufacturing process to create particle samples and particle combinations with better properties than the original sample. Changes in the characteristics and properties of particle samples are determined by many different physical and chemical methods such as ultraviolet-visible spectroscopy (UV-Vis), infrared spectroscopy (IR), noise X-ray radiation (XRD), scanning electron microscope (SEM), dynamic light scattering (DLS), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). Finally, the activity against bacteria, including E. coli and S. aureus, was also tested using the agar well diffusion method to determine the zone of inhibition. The results improved the particle size value, which decreased by half to 200 nm when two additional surfactants, PEG and SDS, were added. In addition, the antibacterial ability has also been shown to increase significantly when the diameter of the bacterial inhibition zone increased significantly, reaching values of 20 mm (Cu2O/Ag/SDS) and 32 mm (Cu2O/Ag/PEG) for the E. coli bacterial strain. The initial test sample was only about 14 mm in size. The S. aureus bacterial strain also had a similar improvement trend after adding Ag to the Cu2O surface with the appearance of two surfactants, SDS and PEG. The inhibition zone diameter values reached the optimal value at 36 mm in the Cu2O/Ag/PEG particle combination sample compared to only the initial 26 mm in the Cu2O particle sample. Finally, the particle samples are added to the acrylic emulsion paint film to evaluate the changes. Positive results were obtained, such as improvement in adhesion (1.22 MPa), relative hardness (240/425), and sand drop resistance (100 L/mil) in the Cu2O/Ag/PEG particle combination sample, which showed the correctness and accuracy of the research.

Electrochemical intercalation of anions into graphite: Fundamental aspects, material synthesis, and application to the cathode of dual‐ion batteries

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Electrochemical intercalation of anions into graphite: Fundamental aspects, material synthesis, and application to the cathode of dual-ion batteries

This article first describes fundamental aspects of the electrochemical intercalation of anions into graphite. Then, the electrochemical preparation of covalent-type graphite intercalation comopouds, especially, graphite oxide and application of graphite as the cathode of dual-ion battery are discussed.


Abstract

In this review, fundamental aspects of the electrochemical intercalation of anions into graphite have been first summarized, and then described the electrochemical preparation of covalent-type GICs and application of graphite as the cathode of dual-ion battery. Electrochemical overoxidation of anion GICs provides graphite oxide and covalent-fluorine GICs, which are key functional materials for various applications including energy storage devices. The reaction conditions to obtain fully oxidized graphite has been mentioned. Concerning the application of graphite for the cathode of dual-ion battery, it stably delivers about 110 mA h g−1 of reversible capacity in usual organic electrolyte solutions. The combination of anion and solvent as well as the concentration of the anions in the electrolyte solutions greatly affect the performance of graphite cathode such as oxidation potential, rate capability, cycling properties, etc. The interfacial phenomenon is also important, and fundamental studies of charge transfer resistance, anion diffusion coefficient, and surface film formation behavior have also been summarized. The use of smaller anions, such as AlCl4 −, Br− can increase the capacity of graphite cathode. Several efforts on the structural modification of graphite and development of electrolyte solutions in which graphite cathode delivers higher capacity were also described.