Dr. Mamo Gebrezgiabher Beyene

Hydrazones, hydrazones-based coinage metal complexes, and their biological applications

Mario Ruben

The spin-crossover (SCO) phenomenon is one of the most prominent examples of bi-stability in molecular chemistry, and the SCO complexes are proposed for nanotechnological applications such as memory units, sensors, and displays. Since the discovery of the SCO phenomenon in tris(N,N-dialkyldithiocarbamato)iron(III) complexes, numerous investigations have been made to obtain bi-stable SCO complexes undergoing spin-state switching at or around room temperature (RT). Valiant efforts have also been made to elucidate the structure–property relationship in SCO complexes to understand the factors—such as ligand-field strength, molecular geometry, and intermolecular interactions—governing the SCO. Schiff base ligands are an important class of nitrogen-rich chelating ligands used to prepare SCO complexes, because the Schiff base ligands are easy to synthesize and tailor with additional functionalities. Iron(II)-Schiff base SCO complexes are a well-studied class of SCO active complexes due to the propensity of the complexes to undergo bi-stable SCO. In this context, this perspective attempts to elucidate the structure–SCO property relationships governing SCO in selected mono-, bi-, and multi-nuclear iron(II)-Schiff base complexes.

19 February 2025 in RSC Advances

Journal Article

Dessie Tafere

Lanthanide-Based Single-Molecule Magnets Derived from Schiff Base Ligands of Salicylaldehyde Derivatives

Fikre Elemo

Taju Sani

Tsegaye Belege Atisme

Ibrahim Nasser Ahmed

Hydrazone-based compounds distinguished by their azomethine –NHNCH group and their respective coinage metal complexes have emerged as leading candidates in the search for effective anticancer and antibiotic agents.

4 December 2020 in Inorganics

Journal Article

Tesfay Gebretsadik Ashebr

Yosef Bayeh Yimer

Gebrehiwot Gebreslassie

Direct Z-Scheme CoFe₂O₄-Loaded g-C₃N₄ Photocatalyst with High Degradation Efficiency of Methylene Blue under Visible-Light Irradiation

The breakthrough in Ln(III)-based SMMs with Schiff base ligands have been occurred for the last decade on account of their magnetic behavior, anisotropy and relaxation pathways. Herein, we review the synthetic strategy, from a structural point of view and magnetic properties of mono, di, tri and polynuclear Ln(III)-based single-molecule magnets mainly with Schiff bases of Salicylaldehyde origin. Special attention has been given to some important breakthroughs that are changing the perspective of this field with a special emphasis on slow magnetic relaxation. An overview of 50 Ln(III)-Schiff base complexes with SMM behavior, covering the period 2008–2020, which have been critical in understanding the magnetic interactions between the Ln(III)-centers, are presented and discussed in detail.

13 March 2023 in Inorganics

Journal Article

Gebrehiwot Gebreslassie

Bin Lin

Madhu Thomas

A C-Doped TiO₂/Fe₃O₄ Nanocomposite for Photocatalytic Dye Degradation under Natural Sunlight Irradiation

Magnetically recyclable direct Z-scheme CoFe₂O₄-loaded g-C₃N₄ photocatalyst material was fabricated using a facile hydrothermal technique and subsequently characterized by XRD, VSM, PL, FT-IR, EDX, DRS, SEM, and BET techniques. The characterization results confirmed that nanoparticles of CoFe₂O₄ are loaded on the surface of g-C₃N₄ sheets. The optical band gap of g-C₃N₄ has been decreased from 2.65 eV to 1.30 eV by means of the loading of CoFe₂O₄ nanoparticles onto the nanosheets of g-C₃N₄. This has enhanced the separation process of electron-hole. Under visible light irradiation, the photocatalytic activity of the developed direct Z-scheme CoFe₂O₄-loaded g-C₃N₄ photocatalyst was evaluated for the photodegradation of methylene blue (MB); during this process the MB decomposed by up to 98.86% in 140 min. Meanwhile, under the same irradiation and time conditions, the g-C₃N₄ and CoFe₂O₄ themselves degraded MB up to 74.92% and 51.53%, respectively. The direct Z-scheme CoFe₂O₄-loaded g-C₃N₄ material was recovered from the solution after the photocatalytic activity using an external magnet and studied to determine its stability. It was shown that the photoactivity did not change significantly after five consecutive cycles.

22 July 2019 in Journal of Composites Science

Journal Article

Tesfay Gebretsadik Ashebr

Gebrehiwot Gebreslassie

Gebretinsae Yeabyo Nigussie

Iron(II) Mediated Supramolecular Architectures with Schiff Bases and Their Spin-Crossover Properties

Magnetically recyclable C-doped TiO₂/Fe₃O₄ (C-TiO₂/Fe₃O₄) nanocomposite was successfully synthesized via a sol–gel method. The synthesized samples were characterized using SEM, energy-dispersive X-ray spectroscopy (EDS), FTIR, and UV-VIS diffuse reflectance spectroscopy (DRS) techniques. The results clearly showed that a C-TiO₂/Fe₃O₄ nanocomposite was produced. The photocatalytic activities of the prepared pristine (TiO₂), C-doped TiO₂ (C-TiO₂) and C-TiO₂/Fe₃O₄ were evaluated by the photodegradation of methyl orange (MO) under natural sunlight. The effect of catalyst loading and MO concentration were studied and optimized. The C-TiO₂/Fe₃O₄ nanocomposite exhibited an excellent photocatalytic activity (99.68%) that was higher than the TiO₂ (55.41%) and C-TiO₂ (70%) photocatalysts within 150 min. The magnetic nanocomposite could be easily recovered from the treated solution by applying external magnetic field. The C-TiO₂/Fe₃O₄ composite showed excellent photocatalytic performance for four consecutive photocatalytic reactions. Thus, this work could provide a simple method for the mass production of highly photoactive and stable C-TiO₂/Fe₃O₄ photocatalyst for environmental remediation.

19 January 2023 in Molecules

Journal Article

Yosef Bayeh Yimer