Two new mononuclear Fe(II) polymorphs, [(CH)N][Fe(pyC-OEt)(NCS)] () and [(CH)N][Fe(pyC-OEt)(NCS)] () (pyC-OEt = tris(pyridin-2-yl)ethoxymethane), have been synthesized and characterized by single-crystal X-ray diffraction, by magnetic and photomagnetic measurements, and by detailed variable-temperature infrared spectroscopy. The molecular structure, in both complexes, is composed of the same anionic [Fe(pyC-OEt)(NCS)] complex (two units for and one unit for ) generated by coordination to the Fe(II) metal center of one tridentate pyC-OEt tripodal ligand and three terminal κ-SCN coligands. Magnetic studies revealed that polymorph displays a high-spin (HS) state over the entire studied temperature range (300-10 K), while complex exhibits an abrupt and complete spin crossover (SCO) transition at ca. 132.3 K, the structural characterizations of which, performed at 295 and 100 K, show a strong modification, resulting from the thermal evolutions of the Fe-N bond lengths and of the distortion parameters (∑ and Θ) of the FeN coordination sphere, in agreement with the presence of HS and low-spin (LS) states at 295 and 100 K, respectively. This thermal transition has been also confirmed by the thermal evolution of the maximum absorbance for ν(NCS) vibrational bands recorded in the temperature range 200-10 K. In the signature of a metastable photoinduced HS state has been observed using photomagnetic and photoinfrared spectroscopy, leading to a similar (LIESST) relaxation temperature (LIESST = light-induced excited spin-state trapping) of 70 K.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.inorgchem.1c00335 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Exploring the equilibrium and non-equilibrium properties of a cooperative trinuclear spin-crossover chain: The role of elastic frustration.
J Chem Phys
January 2025
Université Paris-Saclay, UVSQ, CNRS, GEMaC, 45 Avenue des Etats Unis, 78035 Versailles, France.
Among the large family of spin-crossover (SCO) solids, recent investigations focused on polynuclear SCO materials, whose specific molecular configurations allow the presence of multi-step transitions and elastic frustration. In this contribution, we develop the first elastic modeling of thermal and dynamical properties of trinuclear SCO solids. For that, we study a finite SCO open chain constituted of successive elastically coupled trinuclear (A=B=C) blocks, in which each site (A, B, and C) may occupy two electronic configurations, namely, low-spin (LS) and high-spin (HS) states, accompanied with structural changes.
View Article and Find Full Text PDFSymmetry-breaking spin-state transitions in two of three isostructural salts of MnIII spin-crossover cations, [MnIII(3-OMe-5-NO2-sal2323)]+, with heavy anions are reported. The ReO4- salt undergoes two-step spin crossover which is coupled with a re-entrant symmetry-breaking structural phase transition between a high temperature phase (S = 2, C2/c), an intermediate ordered phase (S = 1/S = 2, P21/c), and a low temperature phase (S = 1, C2/c). The AsF6- complex undergoes an abrupt transition between a high temperature phase (S = 2, C2/c) and a low temperature ordered phase (S = 1/S = 2, P-1).
View Article and Find Full Text PDFA mononuclear iron(II) complex constructed using a complementary ligand pair exhibits intrinsic luminescence-spin-crossover coupling.
Dalton 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 PDFMultistate Transition Metal Carbonyl Bonding Beyond Minimum Energy Pathway: Nonlocality of Spin-Orbit Interaction.
Inorg Chem
January 2025
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
Transition metal carbonyl and transition metal dinitrogen are fundamental chemical complexes in many important biological and catalytic processes. Interestingly, binding between a transition metal (TM) atom and carbonyl or dinitrogen results in spin state change. However, no study has evaluated the spin-orbit (SO) effect along the association pathway of any TM-CO or TM-N bond.
View Article and Find Full Text PDFLarge Polarization Change Induced by Spin Crossover-Driven Fe(II) Ion Shuttling within a Tripodal Ligand.
J Am Chem Soc
January 2025
Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China.
The integration of spin crossover (SCO) magnetic switching and electric polarization properties can engender intriguing correlated magnetic and electric phenomena. However, achieving substantial SCO-induced polarization change through rational molecular design remains a formidable challenge. Herein, we present a polar Fe(II) compound that exhibits substantial polarization change in response to a thermally regulated low-spin ↔ high-spin transition.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!