http://hdl.handle.net/11089/1330 2026-04-07T21:40:10Z http://hdl.handle.net/11089/57802 Photochemical synthesis of carbazole-fused Blatter radicals: effective spin injection to the carbazole system Bartos, Paulina; Szamweber, Patrycja; Camargo, Bruno; Pietrzak, Anna; Kaszyński, Piotr Photocyclization of N-substituted carbazole derivatives of benzo[e][1,2,4]triazine gave two carbazole-fused Blatter radicals with a novel heterocyclic skeleton. No photocyclization was observed for the analogous dibenzocarbazole, indole, benzimidazole, and phenoxazine precursors, which was rationalized with DFT computational methods. The two carbazole-derived radicals were characterized by spectroscopic (UV- vis, EPR) and electrochemical methods, while one of them was analyzed structurally (XRD) and magnetically (SQUID). The latter analysis revealed ferromagnetic interactions in the solid state with 2J/kB = 16.6 K. Properties of these first examples of a new class of stable radicals were analyzed with DFT methods, which confirmed significant impact of the peri-nitrogen atom on electronic properties and additional 15% spin delocalization. 2025-05-27T00:00:00Z http://hdl.handle.net/11089/57801 Ladder-Type Cu(II) Coordination Polymer with π−π Stacking of Planar Blatter Radical Ligands: Structural and Magnetic Characterization Singh, Hemant K.; Smith, Kayla M.; Rawson, Jeremy M.; Camargo, Bruno; Pollett, Ethan S.; Hietsoi, Oleksandr; Friedli, Andrienne C.; Kaszynski, Piotr The synthesis of two C(2)-pyridyl derivatives of the planar Blatter radical was developed by using the tris(trimethylsilyl)silane (TTMSS)-assisted cyclization of appropriate iodoarenes. These monodentate paramagnetic ligands were characterized by spectroscopic (UV−vis and electron paramagnetic resonance (EPR)) and electrochemical methods and reacted with (pdc)Cu(H2O)3. A complex containing the 3-pyridyl group was characterized structurally, revealing novel polymeric Cu−O−Cu−O ladders separated with slipped stacks of radical ligands. Superconducting quantum interference device (SQUID) magnetometry of this complex demonstrated strong antiferromagnetic interactions between the radicals and largely isolated Cu(II) ions. Analysis of the magnetic data with the Hatfield model, assuming two isolated one-dimensional (1D) alternating Heisenberg chains, gave JRR/kB = −1200 K and αRR = 0.4 for the paramagnetic ligand stacks, and JCuCu/ kB = −3.5 K and αCuCu = 0.9 for the Cu(II) ion chains. Analysis of the experimental data was augmented with density functional theory (DFT) calculations. 2025-09-17T00:00:00Z http://hdl.handle.net/11089/57730 Influence of Electrode Polishing Protocols, Potentiostat Models, and LOD Calculation Methods on the Electroanalytical Performance of SWV Measurements at Glassy Carbon Electrodes Świderski, Michał; Seroka, Jagoda; Guziejewski, Dariusz; Krzymiński, Paweł; Miniak-Górecka, Alicja; Koszelska, Kamila; Ullah, Nabi; Smarzewska, Sylwia The aim of this study was to evaluate how fundamental elements of electrochemical measurements influence the results of electroanalytical procedures. Measurements were performed using square wave voltammetry at a glassy carbon electrode, and the analytical signal corresponded to a model redox system. One objective of the study was to examine the impact of potentiostats from different manufacturers, as well as differences between models within the same brand, which varied considerably in cost and measurement capabilities. The influence of the mechanical cleaning procedure for the solid disc electrode surface was also investigated. Three types of polishing motion and different numbers of repetitions were tested. The results showed that polishing motion significantly affects the electroactive surface area of the working electrode and the repeatability of measurements. The largest electroactive surface area and the best repeatability were obtained when polishing was performed using an “8-shaped” motion on the polishing pad. The results confirmed that both instrumentation and electrode polishing procedures can substantially influence statistical parameters describing analytical methods, such as the limit of detection (LOD) and the dynamic range of the calibration curve. Furthermore, applying different approaches for LOD estimation to the same dataset may lead to discrepancies reaching up to two orders of magnitude. 2025-01-01T00:00:00Z http://hdl.handle.net/11089/55038 Dopamine modified electrodes for indirect voltammetric determination of magnesium ions Smarzewska, Sylwia; Mirceski, Valentin; Koszelska, Kamila This article outlines the fabrication process of an electrochemical sensor designed for the innovative determination of magnesium ions based on the electrochemistry of dopamine. The sensor operates under voltammetric conditions, accounting for variations in the electrochemical reversibility of immobilized dopamine in the presence of magnesium ions under conditions of square-wave voltammetry. The immobilization of dopamine on the glassy carbon electrode is achieved through the electrochemical oxidation of its side amino group, leading to covalent grafting onto the electrode surface. All stages of the proposed electrode surface modification procedure were carefully optimized. The dopamine sensor exhibited a linear response in the concentration range of magnesium ions from 0.1 to 10 mmol L-1, with a limit of detection (LOD) value equal to 1.3 × 10−5 mol L−1. To validate the electroanalytical significance of the developed methodology, real food supplement samples were quantitatively analyzed, demonstrating a highly satisfactory rate of recovery. The proposed voltammetric method serves as a simple and cost-effective procedure for the indirect determination of magnesium ions. Additionally, this approach allows for the analysis of real samples without the need for time-consuming preparation steps, as the complex matrices of food supplement samples did not adversely affect the registered currents. 2024-01-01T00:00:00Z