Purposeful ligand design was used for the synthesis of eight new 1D iron(II) spin crossover coordination polymers aiming for cooperative spin transitions with hysteresis. The results from magnetic measurements and X-ray structure analysis show that the combination of rigid linkers and a hydrogen bond network between the 1D chains is a promising tool to reach this goal. Five of the eight new samples show a cooperative spin transition with hysteresis with up to 43 K wide hysteresis loops.
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http://dx.doi.org/10.1039/c3dt52635f | DOI Listing |
Chem Commun (Camb)
January 2025
Department of Chemistry, Quantum Chemistry, TU Darmstadt, Peter-Grünberg-Str. 4, 64287 Darmstadt, Germany.
The two key parameters extracted from Mössbauer spectroscopy, isomer shift and quadrupole splitting, have well-known temperature dependencies. While the behavior of the values following a temperature change has long been known, its microscopic origins are less clear. For quantum chemical calculations - formally representing the situation at 0 K - significant discrepancies with the experiment can arise, especially at elevated temperatures.
View Article and Find Full Text PDFDalton Trans
January 2025
State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, School of Chemical Engineering, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, P. R. China.
Molecular materials that exhibit synergistic coupling between luminescence and spin-crossover (SCO) behaviors hold significant promise for applications in molecular sensors and memory devices. However, the rational design and underlying coupling mechanisms remain substantial challenges in this field. In this study, we utilized a luminescent complementary ligand pair as an intramolecular luminophore to construct a new Fe-based SCO complex, namely [FeLL](BF)·HO (1-Fe, L is a 2,2':6',2''-terpyridine (TPY) derivative ligand and L is 2,6-di-1-pyrazol-1-yl-4-pyridinecarboxylic acid), and two isomorphic analogs (2-Co, [CoLL](BF)·HO and 3-Zn, [ZnLL](BF)·HO).
View Article and Find Full Text PDFR Soc Open Sci
January 2025
Department of Industrial Chemistry, College of Natural and Applied Sciences, Addis Ababa Science and Technology University, PO Box 16417, Addis Ababa, Ethiopia.
The asymmetric Schiff base prepared from ethylenediamine and pyridine-2-carboxaldehyde reacts with Fe(ClO)·6HO to form the Fe(II) complex [FeL](ClO) with L = ,-diethyl-'-(pyridin-2-yl)methylene)ethane-1,2-diamine, where the Fe(III) starting material has been unexpectedly reduced to Fe(II). This complex was characterized by elemental analysis, infrared spectra, single crystal and powder X-ray diffraction measurements, variable temperature DC magnetic measurement and room temperature Mössbauer spectroscopy. The asymmetric ligand L coordinates in a tridentate fashion through its pyridyl, azomethine and amino nitrogen atoms, generating a distorted octahedral geometry around the central metal ion.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Department of Physics, University of Basel, Klingelbergstrasse 82, Basel, 4056, Switzerland.
Many-body interactions in metal-organic frameworks (MOFs) are fundamental for emergent quantum physics. Unlike their solution counterpart, magnetization at surfaces in low-dimensional analogues is strongly influenced by magnetic anisotropy (MA) induced by the substrate and still not well understood. Here, on-surface coordination chemistry is used to synthesize on Ag(111) and superconducting Pb(111) an iron-based spin chain by using pyrene-4,5,9,10-tetraone (PTO) precursors as ligands.
View Article and Find Full Text PDFChemistry
December 2024
Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1a, 52074, Aachen, Germany.
In this study, we present the first experimental determination of the spin state of transition metal complexes by using Hirshfeld Atom Refinement. For the demonstration, the two iron(II) complexes, (NH)Fe(SO) ⋅ 6 HO and lFe(pic)jCl ⋅ EtOH were investigated. The method involves the refinement using wavefunctions of different spin multiplicity and comparison against experimental diffraction data by means of refinement indicators and residual electron density.
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