Control of Chirality, Bond flexing and Anharmonicity in an Electric Field

We located ‘hidden’ S-character chirality in formally achiral glycine using a vector-based interpretation of the total electronic charge density distribution. We induced the formation of stereoisomers in glycine by the application of an electric field. Control of chirality was indicated from the proportionate response to a non-structurally distorting electric field. The bond-flexing was determined to be a measure of bond strain, which could be a factor of three lower or higher, depending on the direction of the electric field, than in the absence of the electric field. The bond-anharmonicity was found to be approximately independent of the electric field. We also compared the formally achiral glycine with the chiral molecules alanine and lactic acid, quantifying the preferences for the S and R stereoisomers. The proportional response of the chiral discrimination to the magnitude and direction of the applied electric field indicated use of the chirality discrimination as a molecular similarity measure.

Electronic structure and magnetization of Zn1-xCoxO ternary alloys with zinc-blende, rocksalt and wurtzite phases

First-principles all electrons density-functional calculations for the band structure and magnetization of Zn1 − xCoxO ternary magnetic alloys, in three phases namely zinc-blende, rocksalt and wurtzite have been reported. The computations are spin-polarized. An inspection of our electronic properties showed that the alloy system of interest exhibits a semiconducting character where the nature of the gap depends on the considered phase. An analysis of electronic charge density suggests that the bonding has a partially covalent character for ZnO which becomes weaker as far as the Co concentration increases. CoO is found to reach a total magnetization of 3 µB per cell for zinc-blende and rocksalt phases and 6 µB per cell for wurtzite phase.

Newly synthesized MAX phase Zr2SeC: DFT insights into physical properties towards possible applications

This is the first time study of the mechanical properties including Vickers hardness and elastic anisotropy, electronic charge density distribution, thermodynamic and optical properties of the synthesized MAX phase Zr2SeC via DFT calculations.

CO2 Electrochemical Reduction by Exohedral N-Pyridine Decorated Metal-Free Carbon Nanotubes

Electrochemical CO2 reduction reaction (CO2RR) to fuels and chemicals represents nowadays one of the most challenging solutions for renewable energy storage and utilization. Among the possible reaction pathways, CO2-to-CO conversion is the first (2e−) reduction step towards the production of a key-feedstock that holds great relevance for chemical industry. In this report we describe the electrocatalytic CO2-to-CO reduction by a series of tailored N-decorated carbon nanotubes to be employed as chemoselective metal-free electrocatalysts. The choice of an exohedral functionalization tool for the introduction of defined N-groups at the outer surface of carbon nanomaterials warrants a unique control on N-configuration and electronic charge density distribution at the dangling heterocycles. A comparative electrochemical screening of variably N-substituted carbon nanomaterials in CO2RR together with an analysis of the electronic charge density distribution at each heterocycle have suggested the existence of a coherent descriptor for the catalyst’s CO faradaic efficiency (FECO). Evidence allows to infer that N-configuration (N-pyridinic vs. N-pyrrolic) of exohedral dopants and electronic charge density distribution at the N-neighboring carbon atoms of each heterocycle are directly engaged in the activation and stabilization of CO2 and its reduction intermediates.

Beryllium Effect on the Energy Band Gaps and the Electronic Charge Density of the Alloy (Be, Cd) Se

In the present study, we have computed the electronic band structure and electronic charge density of the alloy (Be, Cd)Se in the zinc-blende structure; using the local Empirical Pseudopotential Method (EPM), which takes into account the disorder effect into the Virtual Crystal Approximation (VCA) by introducing an effective potential disorder. The obtained results show a reasonable agreement with the available experimental data. Detailed plots of the valence charge distribution along the [111] direction and in the (110) plane are also presented and discussed.

Estimating the effect of electron beam interactions with biological tissues

The stopping power and range for electrons in matter are the most important parameters in predicting the consequences of the electrons interacting with matter. In this work, we used our previously developed method to calculate these parameters. In our calculation method, the main parameter is the velocity-dependent electronic charge density of the target, which we obtained by using Roothaan–Hartree–Fock (RHF) wave functions. For range calculations, we used the continuous slowdown approach (CSDA), which neglects the energy-loss fluctuations so the incident particle loses its energy in a medium continuously at a rate equal to the total stopping power. The stopping power and CSDA range values have been calculated for electrons incident on brain, breast, and eye tissues. Obtained results have been compared with the available data.

“Good Fashion is Evolution, Not Revolution” - Methods to Enhance Existing Anticancer Medicines, Primarily with the Use of Transition Metal

The constant search for successful cancer therapies lasts for decades. Apart from the huge scientific effort and enormous sum of spent money, only a small amount of newly developed medicines move into clinical use (only 94 registered anticancer drugs in the last 12 years). Anticancer regimes are still overcome by drugs invented over 50 years ago such as cisplatin and doxorubicin. Significant progress in the development of improved anticancer drugs was made due to multiple studies on the relationship between the molecular structure of chemical compounds and their cytostatic activity. A number of ligands (mainly organic) with quite effective anticancer properties are known, but they show insufficient activity, selectivity and multidrug resistance. Formation of transition metal – ligand complexes (with proven anticancer effect) changes the properties of the latter. The factors that affect the cytotoxic properties of metal complexes are: the type of ligand and metal, the nature of the connection between metal and ligand, and the distribution of electronic charge density in the formed complexes. Here, we report the recent efforts to improve existing compounds with confirmed anticancer activity. They seem to be unappreciated as their effects appear to be less spectacular than that of targeted anticancer drugs (i.e. based on antibodies or small RNAs).