Article
Chemistry, Inorganic & Nuclear
Zhi-Jian Ouyang, Xiao-Ying Mo, Jia-Qi Ye, Xiao-Xuan Yu, Shu-Yuan Huang, Xiao-Ling Liu, Wen-Bin Chen, Song Gao, Wen Dong
Summary: Two ion-pair Fe(iii) complexes were synthesized by employing the tridentate ligand H(3)ATD, with one in low-spin state and the other undergoing high temperature spin crossover between 360 and 500 K. The magnetic measurements and magneto-structural relationship studies reveal the crucial role of interactions between the cation and anion in the high temperature Fe(iii) behavior.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Inorganic & Nuclear
Zhi-Kun Liu, Zi-Shuo Yao, Jun Tao
Summary: Halogen-substituted Fe(III) compounds with different spin states were synthesized, some of which exhibited light-induced excited spin-state trapping effects and reversible light switching behaviors, providing insights for the development of switchable materials.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Shuwen Jia, Lingyue Fan, Chunyang Zheng, Sai Jin, Dongfeng Li
Summary: A series of cyano-bridged mixed-valence hexanuclear complexes were successfully synthesized by building the units in methanol and ethanol solutions. One of the complexes exhibited a single-crystal-to-single-crystal transformation in water. Detailed analysis of the coordination environment and magnetic susceptibility measurements confirmed their spin-crossover properties.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Daniel Vidal, Jordi Cirera, Jordi Ribas-Arino
Summary: By studying a dataset of 24 different Fe(iii) hexacoordinated complexes, it was demonstrated that the B3LYP* functional is accurate in predicting spin-state energy gaps and distinguishing spin states of Fe(iii) complexes across a range of temperatures. This suggests that B3LYP* is a reliable method for screening new spin-crossover systems with tailored properties.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Rafaela T. Marques, Liliana P. Ferreira, Clara S. B. Gomes, Catia S. D. Lopes, Carlos E. S. Bernardes, Nirod Kumar Sarangi, Tia E. Keyes, Paulo N. Martinho
Summary: The storage of guest molecules in nonporous single crystals is an important development in the field of smart materials. We describe the synthesis and characterization of the new spin crossover Fe(III) compound [Fe(3-Br,5-ClsalEen)2]BPh4 center dot CH3CN center dot H2O (salEen = N-ethyl-N-(2-aminoethyl)salicylaldiminate) and its reversible single-crystal-to-single-crystal transformation upon desolvation and resolvation of the crystals. This compound behaves as a spin crossover sponge, and the desolvation/resolvation dynamics were studied through kinetic analysis.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Inorganic & Nuclear
Norihisa Hoshino, Akari Hayashi, Tomoyuki Akutagawa
Summary: Solids that change their thermal conductivity during a phase transition can be useful in the development of a thermal switch to control heat flow and reduce energy consumption. This study found that the thermal conductivity of spin crossover complexes is greatly affected by spin state transitions, suggesting their potential as candidates for heat transportation switch materials.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Physical
Daniel Vidal, Jordi Cirera, Jordi Ribas-Arino
Summary: Exploring the chemical space of a ligand and modulating its ligand field strength is an effective strategy for fine-tuning the physical properties of spin-crossover complexes. This computational study investigates how ligand substituent effects can modulate the transition temperature (T-1/2) in Fe(iii) SCO systems and identifies suitable descriptors for predicting these changes. The study provides insights into the design of new SCO systems with specific T-1/2 values based on ligand design.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Jett T. Janetzki, Maxim G. Chegerev, Gemma K. Gransbury, Robert W. Gable, Jack K. Clegg, Roger J. Mulder, Guy N. L. Jameson, Alyona A. Starikova, Colette Boskovic
Summary: Spin crossover complexes with the ability to switch between low spin and high spin states have potential applications in sensing, displays, and molecular electronics. This study focuses on dinuclear spin crossover complexes and investigates the influence of bridging ligands on the spin crossover behavior. The synthesis and characterization of three complexes are reported, and both solid-state and solution measurements are performed to gain insights into the interconversion between different spin states.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Malte Oppermann, Francesco Zinna, Jerome Lacour, Majed Chergui
Summary: This study demonstrates trapping of the high-spin state in iron-based spin-crossover complexes by controlling the chiral configuration. The high-spin-state decay is found to be accompanied by changes in optical activity, reflecting coupling to a symmetry-breaking torsional mode. Diastereoselective ion pairing suppresses vibrational population and increases the high-spin-state lifetime. These findings motivate the synthetic control of torsional modes in iron(II) complexes to manipulate their spin-crossover dynamics as a complementary approach.
Article
Chemistry, Multidisciplinary
Suvechhya Lamichhane, Kayleigh A. McElveen, Adam Erickson, Ilja Fescenko, Shuo Sun, Rupak Timalsina, Yinsheng Guo, Sy-Hwang Liou, Rebecca Y. Lai, Abdelghani Laraoui
Summary: [Fe(Htrz)2(trz)](BF4) (Fe-triazole) spin crossover molecules exhibit thermal, electrical, and optical switching between high spin (HS) and low spin (LS) states, making them promising for molecular spintronics. In this study, nitrogen vacancy (NV) based magnetometry is used to investigate the magnetic properties of the Fe-triazole LS state in nanoparticle clusters and individual nanorods. Scanning electron microscopy (SEM) and Raman spectroscopy are employed to determine the size of the nanoparticles/nanorods and confirm their spin states. The results demonstrate the potential of NV quantum sensors for studying the magnetic properties of spin crossover molecules and molecular magnets.
Article
Chemistry, Physical
Rishu Khurana, Sameer Gupta, Md Ehesan Ali
Summary: The study investigated 14 Fe(III) complexes, with nine possessing large zero field splitting parameter D. The ground-spin state was examined using density functional theory (DFT) and multiconfiguration methods, revealing a bias towards high-spin state with the B3LYP functional in cases of near-degenerate spin states. Adjusting the exchange percentage led to an intermediate-spin ground state consistent with multireference calculations.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Physical
Hilaire Mba, Matthieu Picher, Nathalie Daro, Mathieu Marchivie, Philippe Guionneau, Guillaume Chastanet, Florian Banhart
Summary: Spin-crossover particles of [Fe(Htrz)2trz](BF4) with sizes of some hundred nanometers were studied by in situ electron microscopy. Despite their high radiation sensitivity, it was possible to analyze the particles by imaging and diffraction so that a detailed analysis of crystallographic defects in individual particles became possible. The presence of tilt boundaries, where the tilt axis is the direction of the polymer chains, was detected in each particle. The defect structure only changes after a high number of transformations between the low-spin and high-spin phases, which can be explained by the anisotropy of the atomic architecture within the crystals.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Sven Johannsen, Sascha Schueddekopf, Sascha Ossinger, Jan Grunwald, Felix Tuczek, Manuel Gruber, Richard Berndt
Summary: Investigations were conducted on isolated tetramers of the spin crossover compound Fe(H2B-(pyrazole)(pyridylpyrazole))2on Ag(111) at cryogenic temperature using a scanning tunneling microscope (STM) in ultrahigh vacuum. Besides the spin states resulting from electron-induced spin crossover, a third state with distinct current-voltage characteristics and intramolecular image contrast was discovered. This state remains stable within a certain voltage range but decays into the low- and high-spin states of the Fe complex beyond that range. The researchers propose that this state corresponds to a negatively charged Fe complex in its high-spin state, which shares the same number of electrons with the analogous Co compound.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Brian A. Finney, Sabyasachi Roy Chowdhury, Clara Kirkvold, Bess Vlaisavljevich
Summary: By using fully internally contracted (FIC)-CASPT2 analytical gradients, geometry optimizations of spin-crossover complexes have been reported. The study shows that a wave function-based level of theory can be used to optimize the geometries of metal complexes in reasonable times and enable treatment of the molecular geometry and electronic structure of the complexes at the same level of theory. Good overall agreement between DFT and CASPT2 was observed, especially for larger complexes with moderate sized basis sets. Based on efficiency, the recommendation is to use the (10e,12o) active space for convergence to a minimum structure.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Alejandro Martinez Serra, Archit Dhingra, Maria Carmen Asensio, Jose Antonio Real, Juan Francisco Sanchez Royo
Summary: Temperature dependent X-ray photoemission spectroscopy (XPS) was used to study the Fe 2p and N 1s core levels of Fe(ii) spin crossover (SCO) complexes. The Fe 2p core-level spectra showed spin state transitions in these SCO complexes, consistent with previous studies. The temperature dependence of the N 1s core-level binding energy provided further insights into the ligand-to-metal charge transfer phenomenon.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)