A Two-step and Hysteretic Spin-crossover Transition in New Cyano-bridged Hetero-metal FeIIAuI 2-Dimensional Assemblage

Kosone, Takashi; Kachi-Terajima, Chihiro; Kanadani, Chikahide; Saito, Toshiaki; Kitazawa, Takio

doi:10.1246/cl.2008.422

Cited by 44 publications

(29 citation statements)

References 18 publications

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“…Although the magnetic behavior of these samples suggests the existence of two polymorphs, it is difficult to justify them from a crystallographic viewpoint. Interestingly, application of low pressures (0.16 GPa) induces complete two-step spin conversion in the "form 1" [74][75][76]. 4 ] 2´g roups that act as bridges defining infinite layers.…”

Section: Adams and Real Et Almentioning

confidence: 99%

Symmetry Breaking in Iron(II) Spin-Crossover Molecular Crystals

2016

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Abstract:This review provides an up to date survey of a singular class of iron(II) spin crossover (SCO) molecular materials that undergo high-spin (HS) Ø low-spin (LS) phase transitions accompanied by crystallographic symmetry breaking (CSB). Particular interest has been focused on a variety of complexes that exhibit one-step or stepwise SCO behavior and CSB. Most of them afford excellent examples of well-ordered 1HS-1LS, 2HS-1LS or 1HS-2LS intermediate phases (IP) and represent an important platform to disclose microscopic mechanisms responsible for cooperativity and ordering in such multistable materials.

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Section: Adams and Real Et Almentioning

confidence: 99%

Symmetry Breaking in Iron(II) Spin-Crossover Molecular Crystals

2016

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“…However, even if there is a unique SCO center in the crystal, inequivalence between SCO centers may spontaneously originate as a consequence of crystallographic symmetry breaking. Although, crystallographic symmetry breaking giving intermediate steps was previously observed for the mononuclear SCO complexes [Fe 27-29 So far, a relatively small number of complete two-step or incomplete (only one step of two expected) SCO events with symmetry breaking have been observed in mononuclear, [30][31][32][33][34][35][36][37][38][39] polynuclear, [40][41][42][43] and polymeric [44][45][46][47][48][49][50][51][52][53] Fe II SCO complexes, and reviewed recently. 54,55 This phenomenology has also been described for a reduced number of Fe III , [56][57][58][59][60] Co II 61 and Mn III 62 complexes.…”

Section: Introductionmentioning

confidence: 99%

Competing Phases Involving Spin-State and Ligand Structural Orderings in a Multistable Two-Dimensional Spin Crossover Coordination Polymer

Trzop

Valverde‐Muñoz

Piñeiro‐López

et al. 2017

Crystal Growth & Design

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Competition between spin-crossover (SCO) and structural ligand ordering is identified as responsible for multi-stability and generation of six different phases in a rigid two-dimensional (2D) coordination polymer formulated {Fe Furthermore, two additional phases are generated at low temperature. One, LS2 (HS = 0, phase 5), is due to spontaneous symmetry breaking of the LS1 state below 85 K. The other, results from irradiating the low-temperature LS2 phase at 15 K with red light to photo-generate a HS phase of low symmetry (HS*) (HS = 1, phase 6). Detailed structural studies of the six phases unravel the pivotal role played by the internal dihedral angle of the 4,4'-bipy ligands in the microscopic mechanism responsible for multistability and multi-step behavior in 1.Competing phases involving spin-state and ligand structural orderings in a multistable two-dimensional spin crossover coordination polymer INTRODUCTIONIron(II) spin crossover (SCO) complexes are switchable molecular materials that respond to environmental stimuli (T, P, light, analytes) through changes in magnetic, optical, electrical and mechanical properties associated with the high-(HS) and low-spin (LS) states of the SCO centre. The intrinsic on-off nature of the LSHS switch has attracted much interest not only because it constitutes an excellent platform for investigating models of thermal-, pressure and photoinduced phase transitions 1-13 in molecular materials but also because many expectancies have been created regarding to the conception of SCO-based devices, i.e. sensors, actuators and memories. [14][15][16][17][18][19][20][21][22][23][24] This has led to an impressive growth of the SCO field in the last decade as a result of cross-seeding interaction between different areas of research ranging from coordination chemistry, materials science and solid state physics.A pivotal current aspect that transcends the SCO research is the understanding of the elusive principles underlying cooperativity in multi-step spin transitions in the solid-state.Steps may occur when elastic forces favor competition between spatial periodicities of structural inequivalent SCO centers. For example, the presence of crystallographically distinct sites with different ligand field strengths. However, even if there is a unique SCO center in the crystal, inequivalence between SCO centers may spontaneously originate as a consequence of crystallographic symmetry breaking. Although, crystallographic symmetry breaking giving intermediate steps was previously observed for the mononuclear SCO complexes [Fe

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“…In the previous papers, the synthesis and characterization of the closely related bilayer structures of {Fe(X-py) 2 [Au(CN) 2 ] 2 } (X = 3-F (3) [12,13,15], 4-Methyl (4) [17], 3-Br (5) [12], and 3-Br-4-Methyl (6) [16]) have been reported. These analogous compounds are also discussed in this paper.…”

Section: Discussionmentioning

confidence: 99%

“…Since we reported the first Hofmann like SCO coordination polymer {Fe(py) 2 [Ni(CN) 4 ]} n (py = pyridine) [3], many derived types of {Fe II (L) 1~2 [M II (CN) 4 ]} n [4][5][6][7][8][9] and {Fe II (L) 1~2 [M I (CN) 2 ] 2 } n [10][11][12][13][14][15][16][17][18][19][20][21] (M I = Cu, Ag, or Au, M II = Ni, Pd, or Pt, L = pyridine derivatives) have been developed. These compounds show a template 2-dimentional (2-D) sheet structure because of their strongly determinate self-assembly process in which they link octahedral metal centers through the N atoms of the bidentate [Au(CN) 2 ] − unit.…”

Section: Introductionmentioning

confidence: 99%

Modification of Cooperativity and Critical Temperatures on a Hofmann-Like Template Structure by Modular Substituent

Kosone¹,

Kawasaki

Tomori

et al. 2017

Inorganics

Self Cite

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Abstract:In a series of Hofmann-like spin crossover complexes, two new compounds, {Fe(3-F-4-Methyl-py) 2 [Au(CN) 2 ] 2 } (1) and {Fe(3-Methyl-py) 2 [Au(CN) 2 ] 2 } (2) (py = pyridine) are described. The series maintains a uniform 2-dimentional (2-D) layer structure of {Fe[Au(CN) 2 ] 2 }. The layers are combined with another layer by strong aurophilic interactions, which results in a bilayer structure. Both coordination compounds 1 and 2 at 293 K crystallize in the centrosymmetric space groups P2 1 /c. The asymmetric unit contains two pyridine derivative ligands, one type of Fe 2+ , and two types of crystallographically distinct [Au(CN) 2 ] − units. Compound 1 undergoes a complete two-step spin transition. On the other hand, 2 maintains the characteristic of the high-spin state. The present compounds and other closely related bilayer compounds are compared and discussed in terms of the cooperativity and critical temperature. The bilayer structure is able to be further linked by substituent-substituent contact resulting in 3-dimentional (3-D) network cooperativity.

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A Two-step and Hysteretic Spin-crossover Transition in New Cyano-bridged Hetero-metal FeIIAuI 2-Dimensional Assemblage

Cited by 44 publications

References 18 publications

Symmetry Breaking in Iron(II) Spin-Crossover Molecular Crystals

Symmetry Breaking in Iron(II) Spin-Crossover Molecular Crystals

Competing Phases Involving Spin-State and Ligand Structural Orderings in a Multistable Two-Dimensional Spin Crossover Coordination Polymer

Modification of Cooperativity and Critical Temperatures on a Hofmann-Like Template Structure by Modular Substituent

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