A Spin‐Crossover Cluster of Iron(II) Exhibiting a Mixed‐Spin Structure and Synergy between Spin Transition and Magnetic Interaction

Wu, Da Yu; Sato, Osamu; Einaga, Yasuaki; Duan, Chun Ying

doi:10.1002/anie.200804529

Cited by 178 publications

(84 citation statements)

References 45 publications

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“…3; Supplementary Table 3). In both configurations, the grid had a cis-2HS-2LS configuration, abbreviated as [(HS-Fe II ) 2 (LS-Fe II ) 2 ], similar to that described in the first crystallographically determined 2HS-2LS iron grid and the subsequent theoretical studies thereupon 33,34 , although more recently a trans-2HS-2LS grid has also been reported 35 . Increasing the measurement temperature from 100 K to 190 K caused the c axis to double in length, and the unit cell to contain two crystallographically independent sites, both of which were occupied by two overlaid cluster configurations (see Supplementary Fig.…”

Section: Resultsmentioning

confidence: 66%

Programmable spin-state switching in a mixed-valence spin-crossover iron grid

et al. 2014

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Photo-switchable systems, such as discrete spin-crossover complexes and bulk iron-cobalt Prussian blue analogues, exhibit, at a given temperature, a bistability between low-and high-spin states, allowing the storage of binary data. Grouping different bistable chromophores in a molecular framework was postulated to generate a complex that could be site-selectively excited to access multiple electronic states under identical conditions. Here we report the synthesis and the thermal and light-induced phase transitions of a tetranuclear iron(II) grid-like complex and its two-electron oxidized equivalent. The heterovalent grid is thermally inactive but the spin states of its constituent metal ions are selectively switched using different laser stimuli, allowing the molecule to exist in three discrete phases. Site-selective photo-excitation, herein enabling one molecule to process ternary data, may have major ramifications in the development of future molecular memory storage technologies.

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Section: Resultsmentioning

confidence: 66%

Programmable spin-state switching in a mixed-valence spin-crossover iron grid

et al. 2014

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“…7,8 Short-range correlations may also compete with long-range interactions and give rise to deviation from mean-field behaviors, 9 as evidenced in some cases by distinctive long relaxation tails from the LIESST state. 10 Although the vast majority of thermal spin transitions proceed in a single step, there has been an increasing number of two-step transitions reported for polymeric, [11][12][13][14][15][16][17] polynuclear, [18][19][20][21][22][23][24] or mononuclear SCO systems. [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] Such transitions result most frequently from the existence of two crystallographically (symmetrically) independent SCO Fe I I sites with slightly different coordination environments, leading to dissimilar transition temperatures delimiting a plateau (or shoulder), which usually occurs with an approximately equal populations of HS and LS species.…”

Section: Imentioning

confidence: 99%

Multimetastability, phototrapping, and thermal trapping of a metastable commensurate superstructure in a FeIIspin-crossover compound

et al. 2012

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The photoinduced switching and subsequent relaxation regime at cryogenic temperatures of the two-step spin-crossover compound [Fe(bapbpy)(NCS) 2 ] has been investigated by time-dependent photocrystallography. Upon photoexcitation from the low-spin (LS) state, a direct population of the metastable high-spin (HS) state occurs, without involving any intermediate structural state. The relaxation from the metastable HS state in isothermal conditions at 40 K proceeds in two successive steps associated with two symmetry breaking processes. The first step corresponds to the cooperative transformation to an intermediate superstructure, characterized by a long-range-ordered [HS-LS-LS] motif coupled to a commensurate displacive modulation, and concomitant with a tripling of the c axis of the unit cell (C2/c space group). The stabilization of the intermediate state is driven by strong molecule-lattice coupling. In the second stage, the intermediate state undergoes a transformation twinning triggered by lattice strain towards the LS state. The two-step relaxation is reminiscent of the two-step thermal transition of [Fe(bapbpy)(NCS) 2 ] and evidences multimetastability in the light-induced or relaxation regime. The long-range-ordered [HS-LS-LS] superstructure has also been trapped by rapid quench cooling to very low temperature, and has been structurally characterized.

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“…The presence of additional hydrazide group allows preparation of dihydrazones. Despite the fact that mono-and bis-(thio)carbohydrazides are also known to chelate iron, [19][20][21][22][23][24][25] which make them potential RR inhibitors, there are only few investigations published where their anticancer activities were explored, [25][26][27][28][29][30][31][32][33] with no study about their possible mechanism of action.…”

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confidence: 99%

Quinoline based mono- and bis-(thio)carbohydrazones: synthesis, anticancer activity in 2D and 3D cancer and cancer stem cell models

Božić

Marinković

Bjelogrlić³

et al. 2016

RSC Adv.

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A comparative study of antitumor activity of mono-and bis-quinoline based (thio)carbohydrazones was investigated by a series of tests on two human malignant cell lines: acute monocytic leukemia (THP-1) and pancreatic adenocarcinoma cancer stem cells (AsPC-1). Thiocarbohydrazones (TCHs) revealed superior pro-apoptotic activity over carbohydrazones (CHs) on both tested cell phenotypes, also displaying multi-target profile activities. Programmed cell death triggered by TCHs was partially caspasedependent, mainly caspase-8 related. Activity against cancer stem cells (CSCs) was evaluated on 2D monolayers and 3D spheroidal models, where two out of three tested bis-TCHs successfully stimulated apoptosis accompanied by a reduction in size of treated spheres. Additionally, all bis-TCHs induced significant decrease in percentage of CD44-expressing AsPC-1 cells that indicate on their ability to induce reprogramming of CSC phenotype. Current results highly support further assessment of bisTCHs in order to specify their specific targets in cancer cells and particularly in the CSCs subpopulation.

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A Spin‐Crossover Cluster of Iron(II) Exhibiting a Mixed‐Spin Structure and Synergy between Spin Transition and Magnetic Interaction

Cited by 178 publications

References 45 publications

Programmable spin-state switching in a mixed-valence spin-crossover iron grid

Programmable spin-state switching in a mixed-valence spin-crossover iron grid

Multimetastability, phototrapping, and thermal trapping of a metastable commensurate superstructure in a FeIIspin-crossover compound

Quinoline based mono- and bis-(thio)carbohydrazones: synthesis, anticancer activity in 2D and 3D cancer and cancer stem cell models

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