Alexander Greer
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View article: “Blebbing” of a Gold Nanocluster by Dioxygen Insertion into Thiolate Staples during Self-Photooxidation
“Blebbing” of a Gold Nanocluster by Dioxygen Insertion into Thiolate Staples during Self-Photooxidation Open
In our work with a Au thiolate nanocluster (Au20(SG)16, where SG is the tripeptide glutathione), we noticed that it underwent a self-photooxidation reaction in the presence of white light and oxygen. We now report on mechanistic studies us…
View article: Unexpected Suppression of Double-Proton Tunneling Induced by Quantum Barriers from Zero-Point Energy
Unexpected Suppression of Double-Proton Tunneling Induced by Quantum Barriers from Zero-Point Energy Open
To assess tunneling, we studied the guanine-cytosine (GC) base pair tautomerization in the gas phase. We applied multidimensional semiclassical reaction path methodology with microcanonically optimized multidimensional tunneling (μOMT) usi…
View article: Analysis of singlet oxygen transport from air to surface by phosphorescence—slope inflection angle (<scp>SIA</scp>) approach
Analysis of singlet oxygen transport from air to surface by phosphorescence—slope inflection angle (<span>SIA</span>) approach Open
Singlet oxygen ( 1 O 2 ) is a reactive species that plays a role in environmental and biological surface chemistry; however, the mechanisms of the association of airborne 1 O 2 at the air/surface interface are poorly known. Here, we help r…
View article: Catalyst controlled N6 versus Cvinyl arylation of 8-vinyl adenine nucleosides, sequential Cvinyl, N6-diarylation, fluorescence properties, and computational evaluations
Catalyst controlled N6 versus Cvinyl arylation of 8-vinyl adenine nucleosides, sequential Cvinyl, N6-diarylation, fluorescence properties, and computational evaluations Open
Palladium-catalyzed C–N bond forming reactions and Heck arylations involve reaction of an aryl halide at either a nitrogen or carbon atom, respectively. A suitable catalyst-ligand combination and a base are generally employed in both. With…
View article: Mechanistic and Curtin–Hammett Studies of the <sup>1</sup>O<sub>2</sub> Oxidation of a Prenyl Phenol and Phenolate Anion
Mechanistic and Curtin–Hammett Studies of the <sup>1</sup>O<sub>2</sub> Oxidation of a Prenyl Phenol and Phenolate Anion Open
The Curtin–Hammett principle, widely recognized in thermal reactions, has been extended to photosensitization processes in this study, providing new insights into the reactivity of photogenerated singlet oxygen ( 1 O 2 ) with phenol and ph…
View article: Effect of treatment frequency on the efficacy of superhydrophobic antimicrobial photodynamic therapy of periodontitis in a wistar rat model
Effect of treatment frequency on the efficacy of superhydrophobic antimicrobial photodynamic therapy of periodontitis in a wistar rat model Open
Superhydrophobic antimicrobial photodynamic therapy (SH‐aPDT) is advantageous wherein airborne singlet oxygen ( 1 O 2 ) is delivered from a device tip to kill a biofilm with no photosensitizer exposure and no bacterial selectivity (Gram + …
View article: Photosensitized Oxidative Damage from a New Perspective: The Influence of Before-Light and After-Light Reaction Conditions
Photosensitized Oxidative Damage from a New Perspective: The Influence of Before-Light and After-Light Reaction Conditions Open
Photooxidative damage is heavily influenced by the presence of bioactive agents. Conversely, bioactive agents influence the local environment, which in turn is perturbed by photooxidative damage. These sorts of processes give rise to a ver…
View article: Superhydrophobic Dressing for Singlet Oxygen Delivery in Antimicrobial Photodynamic Therapy against Multidrug-Resistant Bacterial Biofilms
Superhydrophobic Dressing for Singlet Oxygen Delivery in Antimicrobial Photodynamic Therapy against Multidrug-Resistant Bacterial Biofilms Open
The rise of antimicrobial resistance poses a critical public health threat worldwide. While antimicrobial photodynamic therapy (aPDT) has demonstrated efficacy against multidrug-resistant (MDR) bacteria, its effectiveness can be limited by…
View article: Singlet oxygen generation on a superhydrophobic surface: Effect of photosensitizer coating and incident wavelength on <scp><sup>1</sup>O<sub>2</sub></scp> yields
Singlet oxygen generation on a superhydrophobic surface: Effect of photosensitizer coating and incident wavelength on <span><sup>1</sup>O<sub>2</sub></span> yields Open
Photochemical generation of singlet oxygen ( 1 O 2 ) often relies on homogenous systems; however, a dissolved photosensitizer (PS) may be unsuitable for some applications because it is difficult to recover, expensive to replenish, and haza…
View article: Abstract 1654 Retro-Diels-Alder Phototruncation of Heptamethine Cyanine to Trimethine Cyanine through an Allene Hydroperoxide Intermediate
Abstract 1654 Retro-Diels-Alder Phototruncation of Heptamethine Cyanine to Trimethine Cyanine through an Allene Hydroperoxide Intermediate Open
Cyanine dyes, which are important class of probes used extensively as antibody and other biomolecule labels, have been found to undergo photoconversion reaction resulting to the formation of species with different absorbance/emission wavel…
View article: Superhydrophobic Tipped Antimicrobial Photodynamic Therapy Device for the <i>In Vivo</i> Treatment of Periodontitis Using a Wistar Rat Model
Superhydrophobic Tipped Antimicrobial Photodynamic Therapy Device for the <i>In Vivo</i> Treatment of Periodontitis Using a Wistar Rat Model Open
Limited options exist for treatment of periodontitis; scaling and root planing (SRP) are not sufficient to eradicate P. gingivalis and the resulting inflammatory disease. Chlorhexidine (CHX), used as an adjuvant to SRP, may reduce bacteria…
View article: A theoretical modeling of NaBr(H2)n clusters as a unique approach in hydrogen gas storage
A theoretical modeling of NaBr(H2)n clusters as a unique approach in hydrogen gas storage Open
Adsorption of H 2 molecules on a bed of NaBr unit for the formation of NaBr(H 2 ) n (n = 1-8) aggregates is reported here theoretically. Second-order Moller-Plesset perturbation calculations were carried out using the MP2/aug-cc-pVDZ level…
View article: Nitric Oxide Detection Using a Chemical Trap Method for Applications in Bacterial Systems
Nitric Oxide Detection Using a Chemical Trap Method for Applications in Bacterial Systems Open
Plant growth-promoting bacteria (PGPB) can be incorporated in biofertilizer formulations, which promote plant growth in different ways, such as fixing nitrogen and producing phytohormones and nitric oxide (NO). NO is a free radical involve…
View article: Role of curvature in acridone for <scp><sup>1</sup>O<sub>2</sub></scp> oxidation of a natural product homoallylic alcohol: A novel <i>iso</i>‐hydroperoxide intermediate
Role of curvature in acridone for <span><sup>1</sup>O<sub>2</sub></span> oxidation of a natural product homoallylic alcohol: A novel <i>iso</i>‐hydroperoxide intermediate Open
A density functional theoretical (DFT) study is presented, implicating a 1 O 2 oxidation process to reach a dihydrobenzofuran from the reaction of the natural homoallylic alcohol, glycocitrine. Our results predict an interconversion betwee…
View article: Practical Aspects in the Study of Biological Photosensitization Including Reaction Mechanisms and Product Analyses: A Do's and Don'ts Guide<sup>†</sup>
Practical Aspects in the Study of Biological Photosensitization Including Reaction Mechanisms and Product Analyses: A Do's and Don'ts Guide<sup>†</sup> Open
The interaction of light with natural matter leads to a plethora of photosensitized reactions. These reactions cause the degradation of biomolecules, such as DNA, lipids, proteins, being therefore detrimental to the living organisms, or th…
View article: Two‐step Two‐intermediate Photorelease Bolm‐McCulla Reaction: Dual Release of Nitrene and Atomic Oxygen Reactive Intermediates
Two‐step Two‐intermediate Photorelease Bolm‐McCulla Reaction: Dual Release of Nitrene and Atomic Oxygen Reactive Intermediates Open
This article is a highlight of the paper by Isor et al. in this issue of Photochemistry and Photobiology . It describes the photolysis of a dibenzothiophene sulfoximine (bearing N ‐phenyl imino and S ‐oxide groups) to produce two reactive …
View article: Photosensitization Reactions of Biomolecules: Definition, Targets and Mechanisms
Photosensitization Reactions of Biomolecules: Definition, Targets and Mechanisms Open
Photosensitization reactions have been demonstrated to be largely responsible for the deleterious biological effects of UV and visible radiation, as well as for the curative actions of photomedicine. A large number of endogenous and exogen…
View article: Antimicrobial Photodynamic Inactivation Using Topical and Superhydrophobic Sensitizer Techniques: A Perspective from Diffusion in Biofilms<sup>†</sup>
Antimicrobial Photodynamic Inactivation Using Topical and Superhydrophobic Sensitizer Techniques: A Perspective from Diffusion in Biofilms<sup>†</sup> Open
This review describes nanoparticle and dye diffusion in bacterial biofilms in the context of antimicrobial photodynamic inactivation (aPDI). aPDI requires the diffusion of a photosensitizer (Sens) into the biofilm and subsequent photoactiv…
View article: Defining the Basis of Cyanine Phototruncation Enables a New Approach to Single-Molecule Localization Microscopy
Defining the Basis of Cyanine Phototruncation Enables a New Approach to Single-Molecule Localization Microscopy Open
The light-promoted conversion of extensively used cyanine dyes to blue-shifted emissive products has been observed in various contexts. However, both the underlying mechanism and the species involved in this photoconversion reaction have r…
View article: <i>Mono</i>‐ and <i>Bis</i>‐Alkylated Lumazine Sensitizers: Synthetic, Molecular Orbital Theory, Nucleophilic Index and Photochemical Studies
<i>Mono</i>‐ and <i>Bis</i>‐Alkylated Lumazine Sensitizers: Synthetic, Molecular Orbital Theory, Nucleophilic Index and Photochemical Studies Open
Mono ‐ and bis ‐decylated lumazines have been synthesized and characterized. Namely, mono ‐decyl chain [1‐decylpteridine‐2,4(1,3 H )‐dione] 6a and bis ‐decyl chain [1,3‐didecylpteridine‐2,4(1,3 H )‐dione] 7a conjugates were synthesized by …
View article: Dark-Binding Process Relevant to Preventing Photosensitized Oxidation: Conformation-Dependent Light and Dark Mechanisms by a Dual-Functioning Diketone
Dark-Binding Process Relevant to Preventing Photosensitized Oxidation: Conformation-Dependent Light and Dark Mechanisms by a Dual-Functioning Diketone Open
Few photosensitizers function in both light and dark processes as they usually have no function when the lights are turned off. We hypothesized that light and dark mechanisms in an α-diketone will be decoupled by dihedral rotation in a con…
View article: Synthesis and Characterization of Ru(II) Complexes with π‐Expansive Imidazophen Ligands for the Photokilling of Human Melanoma Cells
Synthesis and Characterization of Ru(II) Complexes with π‐Expansive Imidazophen Ligands for the Photokilling of Human Melanoma Cells Open
Ru(II) complexes were synthesized with π‐expanding (phenyl, fluorenyl, phenanthrenyl, naphthalen‐1‐yl, naphthalene‐2‐yl, anthryl and pyrenyl groups) attached at a 1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline ligand and 4,4′‐dimethyl‐2,2′‐bipy…
View article: Maltol- and Allomaltol-Derived Oxidopyrylium Ylides: Methyl Substitution Pattern Kinetically Influences [5 + 3] Dimerization versus [5 + 2] Cycloaddition Reactions
Maltol- and Allomaltol-Derived Oxidopyrylium Ylides: Methyl Substitution Pattern Kinetically Influences [5 + 3] Dimerization versus [5 + 2] Cycloaddition Reactions Open
Oxidopyrylium ylides are useful intermediates in synthetic organic chemistry because of their capability of forming structurally complex cycloadducts. They can also self-dimerize via [5 + 3] cycloaddition, which is an oft-reported side rea…