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Spitsyna NG, Lobach AS, Blagov MA, Dremova NN, Dmitriev AI, Zhidkov MV, Simonov SV. Creation of spin switching in graphene oxide-based hybrid film materials with an anionic Fe(III) 5Cl-salicyaldehyde-thiosemicarbazone complex. Dalton Trans 2024. [PMID: 39069880 DOI: 10.1039/d4dt01593b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
The present article describes the synthesis of hybrid composite film materials formed during the self-assembly process through non-covalent interactions of graphene oxide (GO) nanosheets with salt 1, represented by an anionic spin-crossover complex [FeIII(5Cl-thsa)2]- (5Cl-thsa - 5-chlorosalicylaldehyde thiosemicarbazone) and the organic tetraethylammonium cation [Et4N]+. The insertion of the salt 1 molecules into the interlayer space of GO nanosheets with the subsequent formation of a hybrid material GO-1 was observed. The film of the hybrid material GO-1 was characterized by scanning electron and confocal laser microscopy, EDX and XPS analysis, IR, Raman and 57Fe Mössbauer spectroscopy, dc magnetic measurements, and powder X-ray diffraction. Comparison of the magnetic properties of salt 1 and a film of the hybrid material GO-1 demonstrated a significant influence of the GO nanosheets matrix on the completeness of spin transition and showed a slight shift of the hysteresis loop by 1 K in the temperature range of 200-230 K. DFT calculations showed an important role of the organic cation [Et4N]+ in the process of adsorption of the spin-crossover anion [FeIII(5Cl-thsa)2]- on the GO nanosheet surface.
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Affiliation(s)
- Nataliya G Spitsyna
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia.
| | - Anatoly S Lobach
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia.
| | - Maxim A Blagov
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia.
| | - Nadezhda N Dremova
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia.
| | - Alexei I Dmitriev
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia.
| | - Mikhail V Zhidkov
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia.
| | - Sergei V Simonov
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia
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Vennelakanti V, Kilic IB, Terrones GG, Duan C, Kulik HJ. Machine Learning Prediction of the Experimental Transition Temperature of Fe(II) Spin-Crossover Complexes. J Phys Chem A 2024; 128:204-216. [PMID: 38148525 DOI: 10.1021/acs.jpca.3c07104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Spin-crossover (SCO) complexes are materials that exhibit changes in the spin state in response to external stimuli, with potential applications in molecular electronics. It is challenging to know a priori how to design ligands to achieve the delicate balance of entropic and enthalpic contributions needed to tailor a transition temperature close to room temperature. We leverage the SCO complexes from the previously curated SCO-95 data set [Vennelakanti et al. J. Chem. Phys. 159, 024120 (2023)] to train three machine learning (ML) models for transition temperature (T1/2) prediction using graph-based revised autocorrelations as features. We perform feature selection using random forest-ranked recursive feature addition (RF-RFA) to identify the features essential to model transferability. Of the ML models considered, the full feature set RF and recursive feature addition RF models perform best, achieving moderate correlation to experimental T1/2 values. We then compare ML T1/2 predictions to those from three previously identified best-performing density functional approximations (DFAs) which accurately predict SCO behavior across SCO-95, finding that the ML models predict T1/2 more accurately than the best-performing DFAs. In addition, we study ML model predictions for a set of 18 SCO complexes for which only estimated T1/2 values are available. Upon excluding outliers from this set, the RF-RFA RF model shows a strong correlation to estimated T1/2 values with a Pearson's r of 0.82. In contrast, DFA-predicted T1/2 values have large errors and show no correlation to estimated T1/2 values over the same set of complexes. Overall, our study demonstrates slightly superior performance of ML models in comparison with some of the best-performing DFAs, and we expect ML models to improve further as larger data sets of SCO complexes are curated and become available for model training.
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Affiliation(s)
- Vyshnavi Vennelakanti
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Irem B Kilic
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Gianmarco G Terrones
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Chenru Duan
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Heather J Kulik
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Blagov MA, Spitsyna NG, Ovanesyan NS, Lobach AS, Zorina LV, Simonov SV, Zakharov KV, Vasiliev AN. First crystal structure of an Fe(III) anionic complex based on a pyruvic acid thiosemicarbazone ligand with Li +: synthesis, features of magnetic behavior and theoretical analysis. Dalton Trans 2023; 52:1806-1819. [PMID: 36661046 DOI: 10.1039/d2dt03630d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The iron(III) anionic complex based on a pyruvic acid thiosemicarbazone ligand with the lithium cation Li[FeIII(thpy)2]·3H2O (1) has been synthesized and characterized by FTIR spectroscopy, powder and single crystal X-ray diffraction, direct current magnetic susceptibility measurements, and 57Fe Mössbauer spectroscopy. Moreover, the molecular structure of the [Fe(thpy)2]- anion has been determined for the first time. The [Fe(thpy)2]- units in the triclinic P1̄ lattice of 1 are assembled into layers parallel to the bc plane. The Li+ cations and water molecules are located between the layers and the structure is stabilized by hydrogen bonding. The [Fe(thpy)2]- anions form interconnected dimer pairs through hydrogen bonds and short contacts with Fe⋯Fe separation of 6.7861(4) Å. According to dc magnetic measurements, compound 1 demonstrates an incipient spin-crossover transition from the LS (S = 1/2) to the HS (S = 5/2) state above 250 K. The Bleaney-Bowers equation for a model of an isolated LS dimer with a mean-field correction was applied to fit the experimental data of magnetic susceptibility dependence on temperature in the temperature range of 2-250 K. The intra-dimer J1 = -1.79(1) K and inter-dimer J2 = -0.24(3) K antiferromagnetic coupling constants were defined. The analysis of the 57Fe Mössbauer spectra at 80 K and 296 K confirms the presence of the shortened distances between the iron nuclei. Moreover, the influence of the lithium cation on the stabilization of the LS state was shown for the [Fe(thpy)2]- anion. BS-DFT calculations for the optimized structure of two isolated [Fe(thpy)2]- anions also correctly predict a weak exchange J1(calc) = -0.92 K. DFT calculations revealed the OPBE (GGA-type) functional that correctly predicts the spin-crossover transition for the iron(III) thpy compounds. Besides, the effect of the N2O4, N2S2O2, and N2Se2O2 coordination environments on the energy stabilization of the LS state of iron(III) anionic thpy complexes was noted as well.
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Affiliation(s)
- Maxim A Blagov
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia.,Lomonosov Moscow State University, Moscow 119991, Russia
| | - Nataliya G Spitsyna
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia
| | - Nikolai S Ovanesyan
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia
| | - Anatolii S Lobach
- Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia
| | - Leokadiya V Zorina
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia.
| | - Sergey V Simonov
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow region 142432, Russia.
| | | | - Alexander N Vasiliev
- Lomonosov Moscow State University, Moscow 119991, Russia.,National University of Science and Technology "MISiS", Moscow 119049, Russia
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Ghosh S, Kamilya S, Pramanik T, Mohanty A, Rouzières M, Herchel R, Mehta S, Mondal A. Thermo- and photoinduced spin state switching in an iron(II) 2D coordination network associated with large light-induced thermal hysteresis and tuning of dimensionality via ligand modulation. Dalton Trans 2021; 50:7725-7735. [PMID: 33988205 DOI: 10.1039/d1dt00212k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three iron(ii) complexes, [Fe(L1)2(NCS)2(MeOH)2] (1), [Fe(L1)2(NCSe)2(MeOH)2] (2), and [Fe(L2)2(NCS)2]n (3) (L1 = 2,5-dipyridyl-3,4-ethylenedioxythiophene and L2 = 2,5-diethynylpyridinyl-3,4-ethylenedioxythiophene), have been synthesized using redox-active luminescent ethylenedioxythiophene (EDOT)-based ligands, and characterized by variable temperature single-crystal X-ray diffraction, (photo)magnetic, optical reflectivity, and spectroscopy studies. Magneto-structural investigations revealed that 1 and 2 are mononuclear with a FeN4O2 octahedral coordination geometry and remain in a high-spin (HS) (S = 2) state in a temperature range of 2-280 K. Interestingly, a 2D coordination network structure with FeN6 surrounding each iron center was observed for 3, which exhibits reversible thermo-induced spin-state switching between the paramagnetic high-spin (HS) (S = 2) and diamagnetic low-spin (LS) (S = 0) states at around 105 K (T1/2). Furthermore, optical reflectivity and photomagnetic measurements at low temperature confirmed that 3 shows reversible ON/OFF switching between the photoinduced excited paramagnetic HS metastable state and diamagnetic LS state under light irradiation (ON mode using red light and OFF mode using green light). Finally, the photoinduced excited HS state can be reversibly relaxed back to the diamagnetic ground LS state by heating the system at ca. 88 K (TLIESST = 88 K) (light-induced excited spin state trapping (LIESST) effect). Furthermore, 3 also showed an exciting and unique 18 K wide light-induced thermal hysteresis (LITH) effect above liquid nitrogen temperature (100 K). DFT and CASSCF level theoretical calculations were utilized to better understand the magneto-structural correlations of these complexes.
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Affiliation(s)
- Subrata Ghosh
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C V Raman Road, Bangalore 560012, India.
| | - Sujit Kamilya
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C V Raman Road, Bangalore 560012, India.
| | - Titas Pramanik
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C V Raman Road, Bangalore 560012, India.
| | - Ashutosh Mohanty
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C V Raman Road, Bangalore 560012, India.
| | - Mathieu Rouzières
- Univ. Bordeaux, CNRS, Centre de Recherche Paul Pascal, UMR 5031, 33600 Pessac, France
| | - Radovan Herchel
- Department of Inorganic Chemistry, Faculty of Science, Palacký University, CZ-771 46 Olomouc, Czech Republic
| | - Sakshi Mehta
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C V Raman Road, Bangalore 560012, India.
| | - Abhishake Mondal
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Sir C V Raman Road, Bangalore 560012, India.
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Molecular S = 2 High-Spin, S = 0 Low-Spin and S = 0 ⇄ 2 Spin-Transition/-Crossover Nickel(II)-Bis(nitroxide) Coordination Compounds. INORGANICS 2021. [DOI: 10.3390/inorganics9020010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Heterospin systems have a great advantage in frontier orbital engineering since they utilize a wide diversity of paramagnetic chromophores and almost infinite combinations and mutual geometries. Strong exchange couplings are expected in 3d–2p heterospin compounds, where the nitroxide (aminoxyl) oxygen atom has a direct coordination bond with a nickel(II) ion. Complex formation of nickel(II) salts and tert-butyl 2-pyridyl nitroxides afforded a discrete 2p–3d–2p triad. Ferromagnetic coupling is favored when the magnetic orbitals, nickel(II) dσ and radical π*, are arranged in a strictly orthogonal fashion, namely, a planar coordination structure is characterized. In contrast, a severe twist around the coordination bond gives an orbital overlap, resulting in antiferromagnetic coupling. Non-chelatable nitroxide ligands are available for highly twisted and practically diamagnetic complexes. Here, the Ni–O–N–Csp2 torsion (dihedral) angle is supposed to be a useful metric to describe the nickel ion dislocated out of the radical π* nodal plane. Spin-transition complexes exhibited a planar coordination structure in a high-temperature phase and a nonplanar structure in a low-temperature phase. The gradual spin transition is described as a spin equilibrium obeying the van’t Hoff law. Density functional theory calculation indicates that the energy level crossing of the high- and low-spin states. The optimized structures of diamagnetic and high-spin states well agreed with the experimental large and small torsions, respectively. The novel mechanism of the present spin transition lies in the ferro-/antiferromagnetic coupling switch. The entropy-driven mechanism is plausible after combining the results of the related copper(II)-nitroxide compounds. Attention must be paid to the coupling parameter J as a variable of temperature in the magnetic analysis of such spin-transition materials. For future work, the exchange coupling may be tuned by chemical modification and external stimulus, because it has been clarified that the parameter is sensitive to the coordination structure and actually varies from 2J/kB = +400 K to −1400 K.
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Kyoden Y, Ishida T. A Hidden Coordination-Bond Torsional Deformation as a Sign of Possible Spin Transition in Nickel(II)-Bis(nitroxide) Compounds. Molecules 2020; 25:E3790. [PMID: 32825395 PMCID: PMC7503645 DOI: 10.3390/molecules25173790] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 08/13/2020] [Accepted: 08/18/2020] [Indexed: 11/17/2022] Open
Abstract
Complex formation of nickel(II) tetrafluoroborate and tert-butyl 5-phenyl-2-pyridyl nitroxide (phpyNO) in the presence of sodium cyanate gave a discrete molecule [Ni(phpyNO)2(X)2] (X = NCO). The Ni-O-N-Csp2 torsion angles were reduced on heating; 33.5(5)° and 36.2(4)° at 100 K vs. 25.7(10)° and 32.3(11)° at 400 K. The magnetic behavior was almost diamagnetic below ca. 100 K, and the χmT value reached 1.04 cm3 K mol-1 at 400 K. An analysis using the van't Hoff equation indicates a possible spin transition at T1/2 >> 400 K. Density functional theory calculation shows that the singlet-quintet energy gap decreases as the structural change from 100 to 400 K. The geometry optimization results suggest that the diamagnetic state has the Ni-O-N-Csp2 torsion angles of 32.7° while the Stotal = 2 state has those of 11.9°. The latter could not be experimentally observed even at 400 K. After overviewing the results on the known X = Br, Cl, and NCS derivatives, the magnetic behavior is described in a common phase diagram. The Br and Cl compounds undergo the energy level crossing of the high-/low-spin states, but the NCS and NCO compounds do not in a conventional experimental temperature range. The spin transition mechanism in this series involves the exchange coupling switch between ferro- and antiferromagnetic interactions, corresponding to the high- and low-spin phases, respectively.
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Affiliation(s)
| | - Takayuki Ishida
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan;
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Kashiro A, Kohno W, Ishida T. Odd–Even Effect on the Spin-Crossover Temperature in Iron(II) Complex Series Involving an Alkylated or Acyloxylated Tripodal Ligand. Inorg Chem 2020; 59:10163-10171. [DOI: 10.1021/acs.inorgchem.0c01296] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Atsushi Kashiro
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
| | - Wakana Kohno
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
| | - Takayuki Ishida
- Department of Engineering Science, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan
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Muddassir M, Alarifi A, Afzal M, Alowais A, Abduh NAY. Mononuclear High‐spin Octahedral Cobalt(II) Complex with Positive Axial Magnetic Anisotropy: Synthesis, Crystal Structure, and DFT Studies. Z Anorg Allg Chem 2020. [DOI: 10.1002/zaac.202000154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Mohd Muddassir
- Catalytic Chemistry Research Chair Department of Chemistry King Saud University 11451 Riyadh Saudi Arabia
| | - Abdullah Alarifi
- Catalytic Chemistry Research Chair Department of Chemistry King Saud University 11451 Riyadh Saudi Arabia
| | - Mohd Afzal
- Catalytic Chemistry Research Chair Department of Chemistry King Saud University 11451 Riyadh Saudi Arabia
| | - Ahmad Alowais
- Catalytic Chemistry Research Chair Department of Chemistry King Saud University 11451 Riyadh Saudi Arabia
| | - Naaser A. Y. Abduh
- Catalytic Chemistry Research Chair Department of Chemistry King Saud University 11451 Riyadh Saudi Arabia
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Kyoden Y, Ishida T. An indication of spin-transition accompanied by an order-disorder structural transformation in [Ni(phpyNO)2(NCS)2] (phpyNO = tert-butyl 5-phenyl-2-pyridyl nitroxide). RSC Adv 2020; 10:16009-16015. [PMID: 35493632 PMCID: PMC9052934 DOI: 10.1039/d0ra02041a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 04/03/2020] [Indexed: 11/29/2022] Open
Abstract
Reaction of nickel(ii) thiocyanate and tert-butyl 5-phenyl-2-pyridyl nitroxide (phpyNO) afforded a 2p–3d–2p heterospin triad [Ni(phpyNO)2(NCS)2]. The compound crystallizes in the orthorhombic Pbcn space group. The whole molecule is crystallographically independent. The torsion angles around Ni–O–N–C2py are 26.8(4) and 27.3(4)° at 400 K, indicating appreciable orbital overlaps of the radical π* and nickel(ii) 3dx2−y2/3dz2 orbitals. In a low-temperature region, the torsion was enhanced, and the space group changed to monoclinic P21/c with a doubled asymmetric unit volume. The χmT value was practically null below ca. 140 K and, on heating to 400 K, gradually increased and reached 1.30 cm3 K mol−1. A van't Hoff analysis suggests a spin transition at T1/2 = 530(20) K. Density functional theory calculation reproduced ground Stotal = 0 with singlet-triplet gaps of 910 and 1263 K for the 140 K structure, and the gap was reduced to 297 K at 400 K. Consequently, the present compound can be considered as an incomplete spin-crossover material, as a result of T1/2 located above the experimental temperature window. The exchange coupling in [Ni(phpyNO)2(NCS)2] is strongly antiferromagnetic in a low-temperature structure whilst moderately antiferromagnetic in a high-temperature structure.![]()
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Affiliation(s)
- Yukiya Kyoden
- Department of Engineering Science
- The University of Electro-Communications
- Chofu
- Japan
| | - Takayuki Ishida
- Department of Engineering Science
- The University of Electro-Communications
- Chofu
- Japan
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Kyoden Y, Homma Y, Ishida T. High-Spin and Incomplete Spin-Crossover Polymorphs in Doubly Chelated [Ni(L) 2Br 2] (L = tert-Butyl 5-Phenyl-2-pyridyl Nitroxide). Inorg Chem 2019; 58:10743-10755. [PMID: 31368687 DOI: 10.1021/acs.inorgchem.9b00885] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Complexation of nickel(II) bromide with tert-butyl 5-phenyl-2-pyridyl nitroxide (phpyNO) gave two morphs of doubly chelated [Ni(phpyNO)2Br2] as a 2p-3d-2p heterospin triad. The α phase crystallizes in the orthorhombic space group Pbcn. An asymmetric unit involves a half-molecule. The torsion angle around Ni-O-N-C2py is as small as 6.5(3)° at 100 K and 7.0(6)° at 400 K, guaranteeing an orthogonal arrangement between the magnetic radical π* and metal 3dx2-y2 and 3dz2 orbitals. Magnetic study revealed the high-spin ground state with the exchange coupling constant 2J/kB = +288(5) K, on the basis of a symmetrical spin Hamiltonian. The β phase crystallizes in the monoclinic space group P21/n. The whole molecule is an independent unit. The Ni-O-N-C2py torsion angles are 24.2(6) and 37.2(5)° at 100 K and 10.4(7) and 25.9(6)° at 400 K. A magnetic study revealed a very gradual and nonhysteretic spin transition. An analysis based on the van't Hoff equation gave a successful fit with the spin-crossover temperature of 134(1) K, although the susceptibility did not reach the theoretical high-spin value at 400 K. Density functional theory calculation on the β phase showed ground Stotal = 0 in the low-temperature structure while Stotal = 2 in the high-temperature structure, supporting the synchronized exchange coupling switch on both sides. Consequently, the β phase can be recognized as an "incomplete spin crossover" material, as a result of conflicting thermal depopulation effects in a high-temperature region.
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Affiliation(s)
- Yukiya Kyoden
- Department of Engineering Science , The University of Electro-Communications , Chofu, Tokyo 182-8585 , Japan
| | - Yuta Homma
- Department of Engineering Science , The University of Electro-Communications , Chofu, Tokyo 182-8585 , Japan
| | - Takayuki Ishida
- Department of Engineering Science , The University of Electro-Communications , Chofu, Tokyo 182-8585 , Japan
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11
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Abstract
The spin crossover (SCO) between multi-stable states in transition metal material is one of the attractive molecular switching phenomena which is responsive to various external stimuli such as temperature, pressure, light, electromagnetic field, radiation, nuclear decay, soft-X-ray, guest molecule inclusion, chemical environments and so forth [...]
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Kashiro A, Kyoden Y, Okazawa A, Ishida T. Moving Organic Molecules in Crystalline Solids: Gradual Structural Transition and Spin Transition/Crossover. J SYN ORG CHEM JPN 2019. [DOI: 10.5059/yukigoseikyokaishi.77.684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | | | | | - Takayuki Ishida
- Department of Engineering Science, The University of Electro-Communications
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13
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Kashiro A, Some K, Kobayashi Y, Ishida T. Iron(II) and 1,1,1-Tris(2-pyridyl)nonadecane Complex Showing an Order-Disorder-Type Structural Transition and Spin-Crossover Synchronized over Both Conformers. Inorg Chem 2019; 58:7672-7676. [PMID: 31185543 DOI: 10.1021/acs.inorgchem.9b01146] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The title compound (Me4N)[Fe{(2-py)3C- n-C18H37}(NCS)3] having a C18 chain underwent spin-crossover (SCO). There are two crystallographically independent molecules in a triclinic cell at 100 K but only one in a monoclinic cell at 300 K. The complex showed a gradual one-step SCO in the same temperature region as that of the structural transition. The SCO is supported with the 57Fe Mössbauer spectroscopy. The molecules are differentiated on cooling, but the SCO was synchronized.
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Affiliation(s)
- Atsushi Kashiro
- Department of Engineering Science , The University of Electro-Communications , Chofu , Tokyo 182-8585 , Japan
| | - Kanako Some
- Department of Engineering Science , The University of Electro-Communications , Chofu , Tokyo 182-8585 , Japan
| | - Yoshio Kobayashi
- Department of Engineering Science , The University of Electro-Communications , Chofu , Tokyo 182-8585 , Japan
| | - Takayuki Ishida
- Department of Engineering Science , The University of Electro-Communications , Chofu , Tokyo 182-8585 , Japan
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14
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Synthesis and characterization of mixed valence cobalt(III)/cobalt(II) complexes with N,O-donor Schiff base ligands. Polyhedron 2019. [DOI: 10.1016/j.poly.2018.10.059] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Spitsyna NG, Blagov MA, Lazarenko VA, Zorina LV, Vasiliev AN, Krapivin VB, Svetogorov RD, Maximova OV, Simonov SV, Yagubskii EB. Spin-crossover behavior of neutral iron(iii) complexes with salicylaldehyde thio-, seleno- and semicarbazone ligands: experiment and theoretical analysis. Dalton Trans 2019; 48:9328-9336. [DOI: 10.1039/c9dt01404g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A novel neutral complex [FeIII(Hsemsal)(semsal)]·3H2O was synthesized and its magnetic properties, and crystal and electronic structures were studied.
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Affiliation(s)
| | - Maxim A. Blagov
- Institute of Problems of Chemical Physics
- RAS
- Chernogolovka
- Russia
- Lomonosov Moscow State University
| | | | | | - Alexander N. Vasiliev
- Lomonosov Moscow State University
- Moscow 119991
- Russia
- National University of Science and Technology “MISIS”
- Moscow 119991
| | - Vladimir B. Krapivin
- Institute of Problems of Chemical Physics
- RAS
- Chernogolovka
- Russia
- National Research Center “Kurchatov institute”
| | | | - Olga V. Maximova
- Lomonosov Moscow State University
- Moscow 119991
- Russia
- National University of Science and Technology “MISIS”
- Moscow 119991
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Kimura A, Ishida T. Spin-Crossover Temperature Predictable from DFT Calculation for Iron(II) Complexes with 4-Substituted Pybox and Related Heteroaromatic Ligands. ACS OMEGA 2018; 3:6737-6747. [PMID: 31458846 PMCID: PMC6644749 DOI: 10.1021/acsomega.8b01095] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 06/08/2018] [Indexed: 06/10/2023]
Abstract
Spin-crossover (SCO) is a reversible transition between low and high spin states by external stimuli such as heat. The SCO behavior and transition temperature (T 1/2) of a series of [FeII(X-pybox)2](ClO4)2 were studied to establish a methodology for ligand-field engineering, where X-pybox stands for 2,6-bis(oxazolin-2-yl)pyridine substituted with X at the 4-position of the pyridine ring. We utilized X = MeO, Me, 3-thienyl, Ph, H, MeS, 2-thienyl, N3, Cl, Br, 3-pyridyl, and 4-pyridyl. The solution susceptometry on five new derivatives with X = Me, 2-thienyl, N3, Br, and 3-pyridyl was performed in acetone, giving the SCO temperatures of 220, 260, 215, 280, and 270 K, respectively. The density-functional-theory molecular orbital (MO) calculation was performed on the ligands with geometry optimization. The atomic charge on the pyridine nitrogen atom [ρ(Npy)] was extracted from the natural orbital population analysis. Positive correlation appeared in the T 1/2 versus ρ(Npy) plot with R 2 = 0.734, being consistent with the analysis using the Hammett substituent constants (σp and σp +). This finding well agrees with the mechanism proposed: the rich electron density lifts the t2g energy level through the dπ-pπ interaction, resulting in a narrow t2g-eg energy gap and favoring the high-spin state and low T 1/2. The MO method was successfully applied to the known SCO-active iron(II) compounds involving 4-substituted 2,6-bis(pyrazol-1-yl)pyridines. A distinct positive correlation appeared in the T 1/2 versus ρ(Npy) plot. The comparison of correlation coefficients indicates that ρ(Npy) is a more reliable parameter than σp or σp + to predict a shift of T 1/2. Furthermore, this method can be more generalized by application to another known SCO family having 3-azinyl-4-p-tolyl-5-phenyl-1,2,4-triazole ligand series, where azinyl stands for a 2-azaaromatic ring. A good linear correlation was found in the T 1/2 versus ρ(NA) plot (NA is the ligating nitrogen atom in the azaaromatic ring). Finally, we will state a reason why the present treatment is competent to predict the SCO equilibrium position only by consideration on the electronic perturbation.
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