Photochem

9 pages, 3442 KiB

Open AccessCommunication

Time-Resolved Chemiluminescence of Luminol Formed by 355 nm Laser-Irradiated BiVO₄ Photocatalysis: Effects of the Addition of Alcohols and Ag Ions

by Tatsuya Yamazaki and Yoshinori Murakami

Photochem 2024, 4(4), 518-526; https://doi.org/10.3390/photochem4040033 - 19 Dec 2024

Viewed by 755

Abstract

A time-resolved chemiluminescence study of luminol formed by 355 nm laser-irradiated BiVO₄ photocatalysts is reported. It was found that the addition of alcohol to 355 nm laser-irradiated BiVO₄ photocatalysts enhanced the luminol chemiluminescent, but the addition of Ag ions to 355 [...] Read more.

A time-resolved chemiluminescence study of luminol formed by 355 nm laser-irradiated BiVO₄ photocatalysts is reported. It was found that the addition of alcohol to 355 nm laser-irradiated BiVO₄ photocatalysts enhanced the luminol chemiluminescent, but the addition of Ag ions to 355 nm laser-irradiated BiVO₄ photocatalysts reduced the luminol chemiluminescent. The plausible mechanism for the present experimental results is discussed based on the generation and lifetime of active oxygen species formed by 355 nm laser-irradiated BiVO₄ photocatalysts. Full article

► Show Figures

Graphical abstract

7 pages, 200 KiB

Open AccessEditorial

Feature Papers in Photochemistry

by Marcelo I. Guzman

Photochem 2024, 4(4), 511-517; https://doi.org/10.3390/photochem4040032 - 10 Dec 2024

Viewed by 1319

Abstract

As the Special Issues “Feature Papers in Photochemistry” and “Feature Papers in Photochemistry II” conclude, it is crucial to acknowledge the remarkable progress and persistent gaps that continue to shape the journey of photochemistry research [...] Full article

(This article belongs to the Special Issue Feature Papers in Photochemistry II)

10 pages, 333 KiB

Open AccessArticle

Synthesis of Acylated Naphthohydroquinones Through Photo-Friedel–Crafts Acylation and Evaluation of Their Antibiotic Potential

by Alexis Mercier, Alizée Monet, Madyan A. Yaseen, M. Iris Hermanns and Michael Oelgemöller

Photochem 2024, 4(4), 501-510; https://doi.org/10.3390/photochem4040031 - 5 Dec 2024

Cited by 1 | Viewed by 884

Abstract

A variety of 1-(1,4-dihydroxynaphtalen-2-yl) ketones was synthesized using the photo-Friedel–Crafts acylation of 1,4-naphthoquinone with aldehydes. Subsequent oxidation using silver oxide readily furnished the corresponding 2-acylated 1,4 naphthoquinones. Notably, these naphthoquinone derivatives underwent spontaneous partial reduction upon storage. The synthesized compounds were subjected to [...] Read more.

A variety of 1-(1,4-dihydroxynaphtalen-2-yl) ketones was synthesized using the photo-Friedel–Crafts acylation of 1,4-naphthoquinone with aldehydes. Subsequent oxidation using silver oxide readily furnished the corresponding 2-acylated 1,4 naphthoquinones. Notably, these naphthoquinone derivatives underwent spontaneous partial reduction upon storage. The synthesized compounds were subjected to antimicrobial screening. High inhibition effects on Staphylococcus aureus were found for the majority of compounds, which makes them interesting for potential future medicinal applications. Full article

► Show Figures

Figure 1

13 pages, 5106 KiB

Open AccessArticle

Excitation–Emission Fluorescence Mapping Analysis of Microplastics That Are Typically Pollutants

by Syed Atif Iqrar, Aisha Bibi, Raghavan Chinnambedu Murugesan, Daniel Hill and Alex Rozhin

Photochem 2024, 4(4), 488-500; https://doi.org/10.3390/photochem4040030 - 28 Nov 2024

Viewed by 2008

Abstract

Micro- and nanoplastics (MNPs) pose a significant threat to marine and human life due to their immense toxicity. To protect these ecosystems, the development of reliable technologies for MNP detection, characterisation, and removal is vital. While FTIR and Raman spectroscopy are established methods [...] Read more.

Micro- and nanoplastics (MNPs) pose a significant threat to marine and human life due to their immense toxicity. To protect these ecosystems, the development of reliable technologies for MNP detection, characterisation, and removal is vital. While FTIR and Raman spectroscopy are established methods for MNP analysis, fluorescence (FL) spectroscopy has recently emerged as a promising alternative. However, most prior research relies on FL emission probing with a single excitation wavelength for MNP detection. In this study, we introduce a two-dimensional (2D) fluorescence excitation–emission (FLE) mapping method for the detection of commonly found microplastics, namely polystyrene (PS), polyethylene terephthalate (PET), and polypropylene (PP). The FLE mapping technique enables the collective recording of emission spectra across a range of excitation wavelengths, revealing the dominant excitation–emission features of different microplastics. This research advances the field by offering a non-destructive and label-free identification of MNP contamination through the use of FL spectral fingerprints. Full article

(This article belongs to the Special Issue Exclusive Papers of the Editorial Board Members of the Journal Photochem)

► Show Figures

Graphical abstract

14 pages, 3625 KiB

Open AccessArticle

MnO_x and Pd Surface Functionalization of TiO₂ Thin Films via Photodeposition UV Dose Control

by Bozhidar I. Stefanov and Hristo G. Kolev

Photochem 2024, 4(4), 474-487; https://doi.org/10.3390/photochem4040029 - 22 Nov 2024

Viewed by 1400

Abstract

This study investigated the influence of the ultraviolet (UV) dose (

D^{U V}

) on the photodeposition of MnO_x and Pd cocatalysts on 300-nm-thick anatase TiO₂ thin films, which were prepared via sol–gel dip-coating on a glass substrate. MnO_x [...] Read more.

This study investigated the influence of the ultraviolet (UV) dose (

D^{U V}

) on the photodeposition of MnO_x and Pd cocatalysts on 300-nm-thick anatase TiO₂ thin films, which were prepared via sol–gel dip-coating on a glass substrate. MnO_x and Pd were photodeposited using increasing UV doses ranging from 5 to 20 J cm⁻², from 5 mM aqueous electrolytes based on Mn²⁺/IO₃⁻ or Pd²⁺, respectively. The effect of the

D^{U V}

on the MnO_x photodeposition resulted in an increase in Mn²⁺ surface content, from 2.7 to 5.2 at.%, as determined using X-ray photoelectron spectroscopy (XPS). For Pd, increasing the UV dose led to a reduction in the oxidation state, transitioning from Pd²⁺ to Pd⁰, while the overall Pd surface content range remained relatively steady at 2.2–2.4 at.%. Both MnO_x/TiO₂ and Pd/TiO₂ exhibited proportional enhancements in photocatalytic activity towards the degradation of methylene blue. Notably, Pd/TiO₂ demonstrated a significant improvement in photocatalytic performance, surpassing that of pristine TiO₂. In contrast, TiO₂ samples functionalized through wet impregnation and thermal treatment in the same electrolytes showed overall lower photocatalytic activity compared to those functionalized via photodeposition. Full article

► Show Figures

Figure 1

12 pages, 2556 KiB

Open AccessArticle

Effects of Residual Water on Proton Transfer-Switching Molecular Device

by Hiroto Tachikawa

Photochem 2024, 4(4), 462-473; https://doi.org/10.3390/photochem4040028 - 31 Oct 2024

Viewed by 696

Abstract

The excited state proton transfer (ESPT) reaction plays a crucial role in DNA defense and ON-OFF proton-switching molecular devices. o-Hydroxybenzaldehyde (OHBA) is the simplest model-molecule for the ESPT reactions where a proton is transferred from OH to C=O carbonyl groups by photo-excitation. [...] Read more.

The excited state proton transfer (ESPT) reaction plays a crucial role in DNA defense and ON-OFF proton-switching molecular devices. o-Hydroxybenzaldehyde (OHBA) is the simplest model-molecule for the ESPT reactions where a proton is transferred from OH to C=O carbonyl groups by photo-excitation. In the present study, the reaction mechanism of ESPT in OHBA was investigated by means of the direct ab initio molecular dynamics (AIMD) method. The triplet (T₁) state of OHBA, OHBA(T₁), was considered as the excited state of OHBA. The dynamic calculations showed that fast PT occurred from OH to C=O carbonyl groups at the T₁ state. The time of PT was calculated to be 34–57 fs in OHBA(T₁). The spin density was mainly distributed on the benzene ring (Bz) at time zero. The density was gradually transferred from Bz to C=O as a function of time on the T₁ surface. When the spin density on C=O was larger than that on Bz (at time = 35–43 fs), the proton of OH was rapidly transferred to C=O. The localization of spin density on C=O dominated strongly the PT rate. Next, the effects of residual water (H₂O) on the PT rate were investigated using OHBA-H₂O 1:1-complexes to elucidate the effects of H₂O on the PT rate in the ON-OFF proton-switching molecular devices. The PT rates were strongly dependent on the position of H₂O around OHBA. The reaction mechanism is discussed based on theoretical results. Full article

► Show Figures

Graphical abstract

28 pages, 1342 KiB

Open AccessReview

Photodynamic Therapy Review: Past, Present, Future, Opportunities and Challenges

by Yaran Allamyradov, Justice ben Yosef, Berdimyrat Annamuradov, Mahmood Ateyeh, Carli Street, Hadley Whipple and Ali Oguz Er

Photochem 2024, 4(4), 434-461; https://doi.org/10.3390/photochem4040027 - 1 Oct 2024

Cited by 6 | Viewed by 4962

Abstract

Photodynamic therapy (PDT) is a medical treatment that utilizes photosensitizing agents, along with light, to produce reactive oxygen species that can kill nearby cells. When the photosensitizer is exposed to a specific wavelength of light, it becomes activated and generates reactive oxygen that [...] Read more.

Photodynamic therapy (PDT) is a medical treatment that utilizes photosensitizing agents, along with light, to produce reactive oxygen species that can kill nearby cells. When the photosensitizer is exposed to a specific wavelength of light, it becomes activated and generates reactive oxygen that can destroy cancer cells, bacteria, and other pathogenic micro-organisms. PDT is commonly used in dermatology for treating actinic keratosis, basal cell carcinoma, and other skin conditions. It is also being explored for applications in oncology, such as treating esophageal and lung cancers, as well as in ophthalmology for age-related macular degeneration. In this study, we provide a comprehensive review of PDT, covering its fundamental principles and mechanisms, as well as the critical components for its function. We examine key aspects of PDT, including its current clinical applications and potential future developments. Additionally, we discuss the advantages and disadvantages of PDT, addressing the various challenges associated with its implementation and optimization. This review aims to offer a thorough understanding of PDT, highlighting its transformative potential in medical treatments while acknowledging the areas requiring further research and development. Full article

► Show Figures

Figure 1

18 pages, 2259 KiB

Open AccessReview

Metallic Nanoparticles for Surface-Enhanced Raman Scattering Based Biosensing Applications

by Jiro Karlo, Syed S. Razi, Mahamkali Sri Phaneeswar, Arunsree Vijay and Surya Pratap Singh

Photochem 2024, 4(4), 417-433; https://doi.org/10.3390/photochem4040026 - 26 Sep 2024

Viewed by 1854

Abstract

Surface-enhanced Raman scattering (SERS) is a powerful tool for biosensing with high sensitivity, selectivity, and capability of multiplex monitoring for both in vivo and in vitro studies. This has been applied for the identification and detection of different biological metabolites such as lipids, [...] Read more.

Surface-enhanced Raman scattering (SERS) is a powerful tool for biosensing with high sensitivity, selectivity, and capability of multiplex monitoring for both in vivo and in vitro studies. This has been applied for the identification and detection of different biological metabolites such as lipids, nucleic acids, and proteins. The present review article explores the vast applications of metallic nanoparticles for SERS-based biosensing. We have summarized and discussed the fundamental principles, theories, developments, challenges, and perspectives in the field of SERS-based biosensing using different metal nanoparticle substrates namely gold, silver, copper, and bimetallic nanoparticles. Full article

► Show Figures

Figure 1

13 pages, 3827 KiB

Open AccessArticle

Ultrafast Excited State Dynamics of a Verdazyl Diradical System

by Caitlyn Clark, Filip Pawłowski, David J. R. Brook and Christopher Grieco

Photochem 2024, 4(4), 404-416; https://doi.org/10.3390/photochem4040025 - 24 Sep 2024

Viewed by 1484

Abstract

While the photophysics of closed-shell organic molecules is well established, much less is known about open-shell systems containing interacting radical pairs. In this work, we investigate the ultrafast excited state dynamics of a singlet verdazyl diradical system in solution using transient absorption (TA) [...] Read more.

While the photophysics of closed-shell organic molecules is well established, much less is known about open-shell systems containing interacting radical pairs. In this work, we investigate the ultrafast excited state dynamics of a singlet verdazyl diradical system in solution using transient absorption (TA) spectroscopy for the first time. Following 510 nm excitation of the excitonic S₀ → S₁ transition, we detected TA signals in the 530–950 nm region from the S₁ population that decayed exponentially within a few picoseconds to form a vibrationally hot S₀* population via internal conversion. The dependence of the S₁ decay rate on solvent and radical–radical distance revealed that the excited state possesses charge-transfer character and likely accesses the S₀ state via torsional motion. The ultrafast internal conversion decay mechanism at play in our open-shell verdazyl diradicals is in stark contrast with other closed-shell, carbonyl-containing organic chromophores, which exhibit ultrafast intersystem crossing to produce long-lived triplet states as the major S₁ decay pathway. Full article

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Photochem, Volume 4, Issue 4 (December 2024) – 9 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI