EXPRESSION OF CONCERN: Palladium–Schiff base–triphenylphosphine catalyzed oxidation of alcohols ‐ R. ‐ 2010 ‐ Applied Organometallic Chemistry ‐ Wiley Online Library
Applied Organometallic Chemistry, EarlyView.
Monthly Archives: March 2024
Theoretical Investigation of Structural, Electronic and Optical Properties of Cs3MoO4(HCO3) with NLO Active Functional Units
The structural, electronic, optical properties and its structure-property relationship of molybdenyl carbonate Cs3MoO4(HCO3) with NLO active functional units are studied through theoretical perspectives.
Abstract
Employing functional building units with microscopic second-order NLO response has been proposed to explore high performance NLO materials. Herein, structural, electronic and optical properties of non-centrosymmetric molybdenyl carbonate Cs3MoO4(HCO3) with NLO active functional units have been examined based on density functional theory. Theoretical results are consistent with experimentally mentioned data, confirming the reliable method. Detailed geometric structure, electronic attributes, linear optical properties, and nonlinear optical properties of Cs3MoO4(HCO3) are provided. Analysis of structures, compositions of bands and plots of charge density suggest that asymmetric functional building units [MoO4] and [HCO3] exhibit varying degrees of second-order Jahn-Teller distortions, and therefore have a significant impact on the electronic structure and optical properties of Cs3MoO4(HCO3). Maximum absolute value of SHG coefficients at 1064 nm is 0.671 pm/V for d 15, which is nearly twice as much as that of KDP. Further researches are needed in future to validate and enhance optical anisotropy characteristic of Cs3MoO4(HCO3) for satisfying the phase matching conditions. Analysis results indicate that microscopic origins of SHG response in Cs3MoO4(HCO3) are complicated, such as geometric environment, induced polar asymmetric functional building units, and electronic properties. Continuous research on structure-property relationship of NLO materials is needed for exploring more competitive NLO materials.
Intermolecular Insertion Reactions into the P−P Bond of Oligophosphorus Compounds
The intermolecular insertion reactions of small molecules into P−P bonds of oligophosphorus compounds are described. This type of reactivity is important for the development of new, targeted and selective methods for the activation of oligophosphorus compounds to obtain new oligophosphorus ligands and materials.
Abstract
The insertion of unsaturated organic molecules into a P−P bond of oligophosphorus compounds has the potential to expand the organophosphorus and organometallic chemistry and to make it more variable with the selective formation of desirable products. This article reviews the insertion reaction for oligophosphorus compounds and focuses in particular on non-metals, unsaturated organic substrates, carbenes and carbene analogues as starting reagents.
Tailoring Bandgap and Photocatalytic Performance of Designed Zinc Oxide Platelets by Cobalt Doping
Cobalt was successfully doped into the lattice of unique ZnO platelets for the first time. Huge reductions in photocatalytic activity (PCA) were observed compared to that of undoped powders in UVA, UVB, and UVC regions. PCA reduction was explained via tracking the surface hydroxyl groups using XPS analyses.
Abstract
Platelet-shaped zinc oxide (ZnO) particles exhibit certain advantages compared to conventional micron and nano forms. Their superior surface coverage and excellent optical properties make these particles very attractive as UV filters in cosmetics and personal care applications. Although ZnO is non-toxic, it exhibits photocatalytic activity (PCA), which increases when the size of particles approaches the nanoscale. High PCA of mineral/inorganic filters is not desired in cosmetics and personal care applications. Therefore, it is essential to develop strategies to reduce PCA of such materials under UV exposure. Accordingly, the research objective of this study is to develop an understanding of the effects of Co-doping on the optoelectronic and crystal structure of platelet shaped ZnO particles with Zn1-xMxO stoichiometry (x=0-4 wt % cobalt). XRD-based Rietveld refinement and WD-XRF reveal that Co was successfully doped into the ZnO lattice. SEM and particle size analyses confirmed that the shape and size of the designed ZnO platelets did not change significantly after doping. ~85 % reduction in PCA has was achieved by 3 wt % Co doping which was attributed to reduced OH and O2 free radical concentration. These results clearly show that Co-doping can be used to effectively tailor the bandgap and optical properties of the designed ZnO particles.
Modified gold nanoparticles modulated fluorescence and singlet oxygen generation of pheophorbide a as an effective platform for photodynamic therapy against Staphylococcus aureus
Gold nanorods coated with PEG or SiO2 and mixed with pheophorbide a are bactericidal. The efficiency of singlet oxygen generation varied depends on the type of PEG polymer used for coating nanorods. The most effective against bacteria are the mixtures of PEG-coated nanorods with pheophorbide a, exposed to irradiation, which provides a >5.8 log reduction in the bacterial growth.
Abstract
The paper reports on the synthesis and evaluation of photochemical properties of gold nanorods (Au−NRs) coated with PEG with a thiol (−SH) group or SiO2 and their physical mixtures with pheophorbide a. Also biological activity of these systems was tested in photodynamic therapy directed towards Staphylococcus aureus. The potential additive effect between differently functionalized Au−NRs and the dye pheophorbide a was also studied. The efficiency of singlet oxygen generation varied considerably depending on the type of PEG polymer used for coating NRs and was the highest, of 65%, for the polymer PEG (10k) and the Au−NRs concentration of (1.33×10−11 M). For the other studied PEGs (2k, 5k) and the same concentration of NRs, a decrease in the singlet oxygen generation efficiency was observed. The most effective against Gram-positive bacteria were the mixtures of PEG-coated Au−NRs with pheophorbide a, exposed to irradiation at 405 nm and 660 nm, which provided a >5.8 log reduction in the bacteria growth. However, no strong bactericidal effect was noted in the case of irradiation with 525 nm.
Template Assisted One‐Pot Synthesis of [2], Linear [3], and Radial [4]Catenane via Click Reaction
![Template Assisted One-Pot Synthesis of [2], Linear [3], and Radial [4]Catenane via Click Reaction](https://onlinelibrary.wiley.com/cms/asset/4b99974a-5db7-42f8-bde9-26c6e962416e/asia202400031-toc-0001-m.png)
Using a non-labile Co (III) metal template and click reaction followed by de-metalation, synthesis of [2], linear [3], and radial [4] catenane has been achieved. Synthesized templated linear [2] catenane has an additional metal binding site for the synthesis of higher-order catenane through post-functionalization.
Abstract
Design and synthesis of higher order catenane are unexpectedly complex and involve precise cooperation among the precursors overcoming competing and opposing interactions. We achieved synthesis of [2], linear [3], radial [4] in a one-pot reaction by consecutive ring closing through click reactions. This synthesis gave three isolable products due to two, four, and six-click reactions between suitable coupling partners. Yields of the isolate templated-catenane decrease from lower to higher-ordered catenane (40 %, 12 %, and 4 %), probably due to the bite angle as well as the flexibility of the reacting partners. Removal of templating cobalt(III) ion leads to the formation of fully organic [2], linear [3], and radial [4]catenane. These synthesized catenanes were purified by column chromatography and characterized by 1H-NMR, 13C-NMR, and ESI-MS spectroscopy. The synthesized catenanes have free binding sites suitable for post-functionalization and may be used for the synthesis of higher-ordered catenane.
Triplet‐Singlet Emission of d‐Block Metal Complexes Characterized by Spin‐Orbit Natural Transition Orbitals
In the present study, the SO- NTO technique was applied to analyze triplet-to-singlet emission in a set of transition metal complexes with Mo, W, Re, and Ir. The source of intensity in the spin-orbit forbidden transitions has been demonstrated and discussed.
Abstract
Spin-orbit natural transition orbital (SO-NTO) methodology, recently developed in our group for complete and restricted active space (CAS/RAS) wavefunction calculations, is applied to analyze triplet-to-singlet emission in transition metal complexes. The lowest-energy (longest-wavelength) spin-forbidden transition is studied for for [Ir(pbt)2(acac)] and [Re(CO)4(pbt)] and the complexes [W(CO)4(bpy)] and [Mo(CO)4(bpy)]. For the latter complexes, spin-forbidden transitions from higher spin-triplet levels are additionally analyzed. SO-NTOs are compared with spin-free NTOs for the transitions under consideration. The major assignment of a spin-forbidden transition is obtained from the spin-free NTO analysis, while the source of intensity of the electronic transition is revealed by the SO-NTOs.
Adjusting UV‐Vis Spectrum of Alizarin by Insertion of Auxochromes
Adjusting UV-Vis Spectrum of Alizarin: Introduction of an electron-donor group causes the transition bands to be significantly red-shifted whereas electron-withdrawing groups cause a minor blue-shifting.
Abstract
First synthesized in 1868, alizarin became one of the first synthetic dyes and was widely used as a red dye in the textile industry, making it more affordable and readily available than the traditional red dyes derived from natural sources. Despite extensive both experimental and computational analyses on the electronic effects of substituents on the shape of the visible spectrum of alizarin and alizarin Red S, no previous systematic work has been undertaken with the aim to fine tune the dominant absorption region defining its color by introducing other electron-withdrawing or electron-donor groups. For such, we have performed a comprehensive study of electronic effects of substituents in position C3 of alizarin by means of a time dependent DFT approach. These auxochromes attached to the chromophore are proven to alter both the wavelength and intensity of absorption. It is shown that the introduction of an electron-donor group in alizarin causes the transition bands to be significantly red-shifted whereas electron-withdrawing groups cause a minor blue-shifting.
Wearable Electrochemical Sensor for Sweat‐Based Potassium Ion and Glucose Detection in Exercise Health Monitoring
This study developed a wearable device to provide users with real-time insights into their physiological state during exercise. By collecting sweat and utilizing electrochemical techniques, it detects glucose and potassium levels and offers individuals a molecular-level health perspective. It has the potential to aid in disease prevention and exercise motivation.
Abstract
The increasing prevalence of wearable devices has sparked a growing interest in real-time health monitoring and physiological parameter tracking. This study focuses on the development of a cost-effective sweat analysis device, utilizing microfluidic technology and selective electrochemical electrodes for non-invasive monitoring of glucose and potassium ions. The device, through real-time monitoring of glucose and potassium ion levels in sweat during physical activity, issues a warning signal when reaching experimentally set thresholds (K+ concentration at 7.5 mM, glucose concentrations at 60 μM and 120 μM). This alerts users to potential dehydration and hypoglycemic conditions. Through the integration of microfluidic devices and precise electrochemical analysis techniques, the device enables accurate and real-time monitoring of glucose and potassium ions in sweat. This advancement in wearable technology holds significant potential for personalized health management and preventive care, promoting overall well-being, and optimizing performance during physical activities.
First‐Principles Studies on Transition Metal Doped Mo2B2 as Anode Material for Li‐Ion Batteries
Few studies have investigated whether the electrochemical performance of Mo2B2 as an LIB anode material can be improved via doping to increase the charge-discharge rates. In this study, we successfully manipulated Mo2B2 as an LIB anode material via transition-metal doping and screened out better TM-doped Mo2B2, such as Co-doped Mo2B2, to provide theoretical support.
Abstract
New two-dimensional (2D) transition-metal borides have attracted considerable interest in research on electrode materials for Li-ion batteries (LIBs) owing to their promising properties. In this study, 2D molybdenum boride (Mo2B2) with and without transition metal (TM, TM=Mn, Fe, Co, Ni, Ru, and Pt) atom doping was investigated. Our results indicated that all TM-doped Mo2B2 samples exhibited excellent electronic conductivity, similar to the intrinsic 2D Mo2B2 metal behavior, which is highly beneficial for application in LIBs. Moreover, we found that the diffusion energy barriers of Li along paths 1 and 2 for all TM-doped Mo2B2 samples are smaller than 0.30 and 0.24 eV of the pristine Mo2B2. In particular, for 2D Co-doped Mo2B2, the diffusion energy barriers of Li along paths 1 and 2 are reduced to 0.14 and 0.11 eV, respectively, making them the lowest Li diffusion barriers in both paths 1 and 2. This indicates that TM doping can improve the electrochemical performance of 2D Mo2B2 and that Co-doped Mo2B2 is a promising electrode material for LIBs. Our work not only identifies electrode materials with promising electrochemical performance but also provides guidance for the design of high-performance electrode materials for LIBs.