Adamantyl Side Chains as Anti-Aggregating Moieties in Dyes for Dye-Sensitized Solar Cells

Designing and evaluating novel dye concepts is crucial for the development of the field of dye-sensitized solar cells (DSSCs). In our recent report, the novel concept of tethering the anti-aggregation additive chenodeoxycholic acid (CDCA) to dyes for DSSC was introduced. Based on the performance improvements seen for this modification, the aim of this study is to see if a simplified anti-aggregation unit could achieve similar results. The following study reports the synthesis and photovoltaic characterization of two novel dyes decorated with the steric ethyladamantyl moiety on the π-spacer, and on the triarylamine donor. This modification is demonstrated to be successful in increasing the photovoltages in devices employing copper-based electrolytes compared to the non-modified reference dye. The best photovoltaic performance is achieved by a device prepared with the adamantyl decorated donor dye and CDCA, this device achieves a power conversion efficiency of 6.1 % (Short-circuit current=8.3 mA cm⁻², Open-circuit voltage=1054 mV, Fill factor=0.69). The improved photovoltaic performance seen for the adamantyl decorated donor demonstrate the potential of ethyladamantyl side chains as a tool to ensure surface protection of TiO₂.     

An iron carbonyl approach to the influenza neuraminidase inhibitor oseltamivir

A novel synthetic route towards oseltamivir, an influenza neuraminidase inhibitor, has been achieved employing a cationic iron carbonyl complex, providing an alternate pathway with the potential to access diverse analogues.     

Vibrational OH-stretching overtone spectroscopy of jet-cooled resorcinol and hydroquinone rotamers

We have measured the OH-stretching fundamental and overtone spectra of resorcinol and hydroquinone in a supersonic jet using nonresonant ionization detected infrared/near-infrared spectroscopy. Anharmonic oscillator local mode calculations of the OH-stretching frequencies and intensities and Boltzmann populations of the stable rotamers have been calculated at the B3LYP/6-311++G(3df,2pd) level to help interpret the observed spectra. Resorcinol has three stable rotamers and in the recorded second and third OH-stretching overtone spectra there is evidence of two distinguishable rotamers. Hydroquinone has two stable rotamers; however, the OH-stretching oscillators of each rotamer are so similar in nature that even up to the fourth OH-stretching overtone the transitions coincide. These results place a limit on the ability of the jet-cooled overtone spectroscopy technique to distinguish between rotamers.     

Enhanced stability of symmetrical polymer electrolyte membrane fuel cell single cells based on novel hierarchical microporous-mesoporous carbon supports

Fuel cell electrodes were prepared from Pt nanocluster activated hierarchical microporous-mesoporous carbon powders. The carbon supports were synthesized from molybdenum carbide applying the high-temperature chlorination method. Six different synthesis temperatures within the range from 600 to 1000 °C were used for preparation of carbon supports. Thermogravimetric analysis, X-ray diffraction, low-temperature nitrogen sorption, and high-resolution scanning electron microscopy methods were used to characterize the structure of the electrode materials and symmetrical membrane electrode assemblies (MEAs). The MEAs prepared were used to conduct the proton exchange membrane fuel cell (PEMFC)single-cell measurements. The polarization and power density curves for single cells were calculated to evaluate the activity of the catalyst materials synthesized. The electrochemically active surface area (from 2.4 to 11.9 m² g^?1) was obtained in order to estimate the contact surface areas of platinum and Nafion® electrolyte. The values of the electrolyte resistance, polarization resistance, and cell degradation rate were calculated from electrochemical impedance spectroscopy data. The carbon materials synthesized within temperature range from 600 to 850 °C were found to be the most suitable supports for PEMFCs, having higher maximum power density values and better stability (cell potential degradation 240 μV h^?1) than commercial carbon-based (Vulcan XC72; 670 μV h^?1) single cells.     

Electronic structure calculations of small Al n (n=2–8) clusters

The electronic states of small Al _n (n=2–8) clusters have been calculated with a relativistic ab-initio MO-LCAO Dirac-Fock-Slater method using numerical atomic DFS wave-functions. The excitation energies were obtained from a ground state calculation of neutral clusters, and in addition from negative clusters charged by half an electron in order to account for part of the relaxation. These energies are compared with experimental photo-electron spectra.     

An amino acid based system for CO2 capture and catalytic utilization to produce formates

Herein, we report a novel amino acid based reaction system for CO₂ capture and utilization (CCU) to produce formates in the presence of the naturally occurring amino acid l-lysine. Utilizing a specific ruthenium-based catalyst system, hydrogenation of absorbed carbon dioxide occurs with high activity and excellent productivity. Noteworthy, following the CCU concept, CO₂ can be captured from ambient air in the form of carbamates and converted directly to formates in one-pot (TON > 50 000). This protocol opens new potential for transforming captured CO₂ from ambient air to C1-related products.

A novel amino acid based reaction system for CO₂ capture and utilization (CCU) to produce formates is presented applying a ruthenium-based catalyst. Noteworthy, CO₂ can be captured from ambient air and converted to formates in one-pot (TON > 50 000).     

The Effects of Structural Alterations in the Polyamine and Amino Acid Moieties of Philanthotoxins on Nicotinic Acetylcholine Receptor Inhibition in the Locust,Schistocerca gregaria

Alterations in the polyamine and amino acid (tyrosine) moieties of philanthotoxin-343 (PhTX-343) were investigated for their effects on the antagonism of nicotinic acetylcholine receptors (nAChRs) isolated from the locust (Schistocerca gregaria) mushroom body. Through whole-cell patch-clamp recordings, the philanthotoxin analogues in this study were shown to cause inhibition of the inward current when co-applied with acetylcholine (ACh). PhTX-343 (IC₅₀ = 0.80 μM at −75 mV) antagonised locust nAChRs in a use-dependent manner, suggesting that it acts as an open-channel blocker. The analogue in which both the secondary amine functionalities were replaced with methylene groups (i.e., PhTX-12) was ~6-fold more potent (IC₅₀ (half-maximal inhibitory concentration) = 0.13 μM at −75 mV) than PhTX-343. The analogue containing cyclohexylalanine as a substitute for the tyrosine moiety of PhTX-343 (i.e., Cha-PhTX-343) was also more potent (IC₅₀ = 0.44 μM at −75 mV). A combination of both alterations to PhTX-343 generated the most potent analogue, i.e., Cha-PhTX-12 (IC₅₀ = 1.71 nM at −75 mV). Modulation by PhTX-343 and Cha-PhTX-343 fell into two distinct groups, indicating the presence of two pharmacologically distinct nAChR groups in the locust mushroom body. In the first group, all concentrations of PhTX-343 and Cha-PhTX-343 inhibited responses to ACh. In the second group, application of PhTX-343 or Cha-PhTX-343 at concentrations ≤100 nM caused potentiation, while concentrations ≥ 1 μM inhibited responses to ACh. Cha-PhTX-12 may have potential to be developed into insecticidal compounds with a novel mode of action.     

Inter-laboratory exercise with an aim to compare methods for 90Sr and 239,240Pu determination in environmental soil samples

In order to deliver reliable results for a multitude of different scenarios, e.g. emergency preparedness, environmental monitoring, nuclear decommissioning and waste management, there is a constant process of method development in the field of radioanalytical chemistry. This work presents the results of a method comparison exercise aimed at quantifying ⁹⁰Sr and ^239,240Pu in environmental soil samples, with the intention of evaluating the performance and applicability of different methods. From the methods examined in this work, recommendations are given in order to find a radioanalytical measurement procedure, for ⁹⁰Sr and ^239,240Pu analysis, which is fit-for-purpose for a particular scenario.

     

Detection of the hydrogen-bond stretching mode in the low-frequency Raman spectrum of catechol and catechol-D2

Low-frequency Raman spectra of catechol (1,2-dihydroxybenzene) and catechol-d₂ have been measured at 130 K. The stretching mode of the intermolecular hydrogen bond, ν_σ, has been assigned at 187 and 184 cm^?1, respectively. A short discussion of this assignment and its implications with respect to the previously reported guaiacol (2-methoxyphenol) spectra is presented.