In this work, the multiferroic bismuth ferrite materials Bi0.9RE0.1FeO3 doped by rare-earth (RE = La, Eu, and Er) elements were obtained by the solution combustion synthesis. Structure, electrical, and magnetic properties of prepared samples were investigated by X-ray photoelectron spectroscopy, Mössbauer spectroscopy, electrical hysteresis measurement, broadband dielectric spectroscopy, and SQUID magnetometry. All obtained nanomaterials are characterized by spontaneous electrical polarization, which confirmed their ferroelectric properties. Investigation of magnetic properties at 300.0 K and 2.0 K showed that all investigated Bi0.9RE0.1FeO3 ferrites possess significantly higher magnetization in comparison to bismuth ferrites obtained by different methods. The highest saturation magnetisation of 5.161 emu/g at 300.0 K was observed for the BLaFO sample, while at 2.0 K it was 12.07 emu/g for the BErFO sample. Several possible reasons for these phenomena were proposed and discussed.

Tiny changes in the covalent structure of a noble-metal-anchored peptide may affect its surface-enhanced Raman scattering (SERS) signature. While SERS spectra of Cys-Trp peptides are dominated by the bands arising from the aromatic Trp side chain, a thorough study of the impact of modifications in SERS-silent regions concerning such dipeptides was yet to be performed. Thus, here we conduct an extensive SERS study of a series of Cys- and Trp-containing dipeptides, varying both the main-chain direction (Cys-Trp/Trp-Cys) and the presence of typical covalent modifications at N- and C-termini (acetylation/amidation). We use three different SERS-active substrates: oxidation–reduction cycling-roughened silver (Ag ORC), gold (Au ORC), and chemically synthesized colloidal silver nanoparticles (Ag NPs). Interpretation of the experimental data was aided with density functional theory (DFT) calculations. Potential energy distribution (PED) analysis was used for the assignment of dipeptide vibrational bands. IR and normal Raman spectra were also examined to get a complete vibrational analysis. This work may be considered the first report on the effect of terminal group modification and reversing the peptide sequence on the adsorptive behavior of dipeptide on silver and gold surface studied by SERS spectroscopy, supported by full vibrational assignment by means of the DFT method.

Nanocomposites combining magnetic and plasmonic properties are very attractive within the field of surface-enhanced Raman scattering (SERS) spectroscopy. Applications presented so far take advantage of not only the cooperation of both components but also synergy (enhanced properties), leading to multi-approach analysis. While many methods were proposed to synthesize such plasmonic-magnetic nanoparticles, the issue of their collective magnetic behavior, inducing irreversible self-aggregation, has not been addressed yet. Thus, here we present a simple and fast method to overcome this problem, employing 2-mercaptoethanesulfonate (MES) ions as both a SERS tag and primer molecules in the silica-coating process of the previously fabricated Fe3O4/Ag nanocomposite. The use of MES favored the formation of silica-coated nanomaterial comprised of well-dispersed small clusters of Fe3O4/Ag nanoparticles. Furthermore, adsorbed MES molecules provided a reliable SERS response, which was successfully detected after magnetic assembly of the Fe3O4/Ag@MES@SiO2 on the surface of the banknote. Improved chemical stability after coating with a silica layer was also found when the nanocomposite was exposed to suspension of yeast cells. This work reports on the application of 2-mercaptoethanesulfonate not only providing a photostable SERS signal due to a non-aromatic Raman reporter but also acting as a silica-coating primer and a factor responsible for a substantial reduction of the self-aggregation of the plasmonic-magnetic nanocomposite. Additionally, here obtained Fe3O4/Ag@MES@SiO2 SERS nanotags showed the potential as security labels for the authentication purposes, retaining its original SERS performance after deposition on the banknote.

Three new compounds, namely [HL]2+[CuCl4]2−, [HL]2+[ZnCl4]2−, and [HL]2+[CdCl4]2− (where L: imipramine) were synthesized and their physicochemical and biological properties were thoroughly investigated. All three compounds form isostructural, crystalline systems, which have been studied using Single-Crystal X-ray diffraction analysis (SC-XRD) and Fourier-transform infrared spectroscopy (FTIR). The thermal stability was investigated using thermogravimetric analysis (TGA) and melting points for all compounds have been determined. Magnetic measurements were performed in order to study the magnetic properties of the compounds. The above mentioned techniques allowed us to comprehensively examine the physicochemical properties of the newly obtained compounds. The biological activity was investigated using the number of Zebrafish tests, as it is one of the most common models for studying the impact of newly synthesized compounds on the central nervous system (CNS), since this model is very similar to the human CNS.

Decoding of atomic and ionic radii of transition metals in terms of energy response against changes in electron number and external potential variation has been considered. Energy as a functional of electron density by means of its derivatives is linked to response density and the electron detachment process. Employing charge sensitivity analysis and the electronegativity equalization principle, we interpret the electronic structure transformations (electron-following/preceding perspectives) into atomic diameters. Additionally, qualitative associations described within hard/soft acid/base theory and the approximate correlations of respective conceptual density functional theory reactivity descriptors were considered to meet postulates of the correspondence principle, giving the characteristic radius the attribute of latent variable related to quantum mechanical observables. By means of local density approximation, an insight from statistical analysis of frontier electron density complements the picture of classical (electrostatic) radii formulations as well as provides a view on the electron correlation effect on the atomic size. The presented radius identifies ground and excited states, as well as spin configurations through measurable properties. Its correspondence with empirical radii is illustrated. The provided mathematical interpretation associated with energy evolution contrasts with the classically understood physical boundary.