Synergetic Spin Crossover and Fluorescence in One‐Dimensional Hybrid Complexes

Wang, Chunfeng; Li, Renfu; Chen, Xueyuan; Wei, Rong; Zheng, Lan‐Sun; Tao, Jun

doi:10.1002/anie.201410454

Cited by 151 publications

(109 citation statements)

References 30 publications

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“…This observation has consequences for the design of fluorescent spin-crossover compounds, which have been pursued by several groups with mixed success. [40][41][42][43][44][45][46] The strongest coupling between spin-crossover and emission has been achieved using remote fluorophores tethered to iron complex centers, either in individual molecules 40,41 or more complex nanostructures. 42,43 This antenna effect may be a more promising approach towards multifunctional fluorescent switches, than compounds where the emissive group is directly ligated to the iron center as in this work.…”

Section: Resultsmentioning

confidence: 99%

Iron(II) Complexes of Tridentate Indazolylpyridine Ligands: Enhanced Spin-Crossover Hysteresis and Ligand-Based Fluorescence

et al. 2015

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ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. ABSTRACTReaction of 2,6-difluoropyridine with 2 equiv indazole and NaH at room temperature affords a mixture of 2,6-bis(indazol-1-yl)pyridine (1-bip), 2-(indazol-1-yl)-6-(indazol-2-yl)pyridine (1,2-bip) and 2,6-bis(indazol-2-yl)pyridine (2-bip), which can be separated by solvent extraction. A two-step procedure using the same conditions also affords both 2-(indazol-1-yl)-6-(pyrazol-1-yl)pyridine (1-ipp) and 2-(indazol-1-yl)-6-(pyrazol-2-yl)pyridine (2-ipp). These are all annelated analogues of 2,6-di(pyrazol-1-yl)pyridine, an important ligand for spin-crossover complexes.Iron (

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Section: Resultsmentioning

confidence: 99%

Iron(II) Complexes of Tridentate Indazolylpyridine Ligands: Enhanced Spin-Crossover Hysteresis and Ligand-Based Fluorescence

et al. 2015

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“…Since SCO can be induced by external stimuli such as temperature, pressure, magnetic field, and light, SCO complexes have aroused growing attention as externally-controllable molecular materials [1,2]. Recently the applications of SCO complexes toward memory, display, and sensing devices as well as the development of multifunctional SCO compounds combining SCO with electronic properties such as electrical conductivity [3][4][5][6][7], magnetic property [8][9][10][11][12], and optical property [13,14] are actively studied.…”

Section: Introductionmentioning

confidence: 99%

The Role of Coulomb Interactions for Spin Crossover Behaviors and Crystal Structural Transformation in Novel Anionic Fe(III) Complexes from a π-Extended ONO Ligand

et al. 2016

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Abstract:To investigate the π-extension effect on an unusual negative-charged spin crossover (SCO) Fe III complex with a weak N 2 O 4 first coordination sphere, we designed and synthesized a series of anionic Fe III complexes from a π-extended naphthalene derivative ligand. Acetonitrile-solvate tetramethylammonium (TMA) salt 1 exhibited an SCO conversion, while acetone-solvate TMA salt 2 was in a high-spin state. The crystal structural analysis for 2 revealed that two-leg ladder-like cation-anion arrays derived from π-stacking interactions between π-ligands of the Fe III complex anion and Coulomb interactions were found and the solvated acetone molecules were in one-dimensional channels between the cation-anion arrays. A desolvation-induced single-crystal-to-single-crystal transformation to desolvate compound 2' may be driven by Coulomb energy gain. Furthermore, the structural comparison between quasi-polymorphic compounds 1 and 2 revealed that the synergy between Coulomb and π-stacking interactions induces a significant distortion of coordination structure of 2.

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“…liquid crystal phase transition). One possibility to achieve such systems is the synthesis of composite materials such as thin films doped with SCO complexes for electroluminescence, 9 functionalised SCO-core-luminescence-shell nanoparticles 10,11 or SCO complexes with fluorescent counter anions. 2,3 Iron(II) is the most widely used metal centre for the synthesis of SCO complexes.…”

Section: Introductionmentioning

confidence: 99%

“…2,3 Iron(II) is the most widely used metal centre for the synthesis of SCO complexes. 11,13 However, this approach is not always successful with respect to a coupling between spin transition and fluorescence. However, the phenomenon itself is not limited to iron(II) or other 3d 4-7 metal centres with an octahedral coordination sphere.…”

Section: Introductionmentioning

confidence: 99%

Modulation of the ligand-based fluorescence of 3d metal complexes upon spin state change

et al. 2015

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Two new Schiff base-like ligands bearing a heteroaromatic fluorophore were synthesised and converted into the corresponding Ni(II), Cu(II) and Zn(II) square planar complexes. The Ni(II) complexes were studied with regard to a coordination change-induced spin state change upon addition of pyridine in solution. An inverse correlation between the fluorescence properties and the spin state of the metal centre was observed, and investigated with steady state fluorescence and time-resolved spectroscopy. RESULTS SynthesesAll metal complexes were synthesised in two steps. Starting with the diamines 1 and 4, firstly a condensation with a ketoenol ether forms the chelate cycles, which then react with metal acetate to give the respective complexes [ML1] and [ML2] (M = Ni II , Cu II , Zn II ), the counter anionic acetates acting as bases for deprotonation of the ligand. The molecular structures and the synthetic pathway are given in Scheme 1. All complexes were obtained as pure powder with the general formula [ML1] or [ML2]. All ligands and intermediates were characterised with IR, CHN and 1 H-NMR. All complexes were characterised with IR, CHN analysis and mass spectrometry. Scheme 1. Pathway of synthesis of the metal complexes described in this work and used abbreviations. Crystal structure analysisSingle crystals suitable for X-ray diffraction analysis of [NiL1] and [CuL1] were obtained from a vapour-vapour slow diffusion setup between a trichloromethane solution of the complex and ethanol. All crystallographic data are given in the Supporting Information: Table S1. While the complex [NiL1] crystallises with the same composition as the bulk material, the structure of compound [CuL1] was determined as [CuL1(EtOH)]•2 CHCl 3 . Both compounds crystallise in the triclinic space group P-1, and the asymmetric units contain one complex molecule. ORTEP drawings of the asymmetric units are displayed in Figure 1. The nickel(II) centre in [NiL1] lies in a N 2 O 2 square planar coordination sphere. Ni-N (1.83 Å) and Ni-O eq (1.85 Å) bond lengths are in agreement with other complexes with similar coordination sphere. 16,17 The sum of the angles is with Σ = 717°, not far from a perfect square planar coordination sphere (Σ = 720°). In the case of [CuL1(EtOH)]•2 CHCl 3 , the copper(II) lies in a N 2 O 3 square pyramidal geometry. Cu-N (1.92 Å), Cu-O eq (1.92 Å) and Cu-O EtOH (2.378(5) Å) bond lengths are generally longer than for the nickel complex, due to the different geometry of the coordination sphere and the increase of the covalent radius from 124 pm (Ni) to 132 pm (Cu). Selected bond lengths and angles are presented in Table 1.The crystal packing of [NiL1] shows the complexes stacked over each other, forming columns along the vector [100]. π-π interactions between the aromatic rings of the ligand, as well as metal-aromatic interactions between the nickel centre and the chelate rings of neighbouring complexes lead to the formation of the columns in the packing. Illustrations of the packing are shown in Figure 2, and selected distance...

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Synergetic Spin Crossover and Fluorescence in One‐Dimensional Hybrid Complexes

Cited by 151 publications

References 30 publications

Iron(II) Complexes of Tridentate Indazolylpyridine Ligands: Enhanced Spin-Crossover Hysteresis and Ligand-Based Fluorescence

Iron(II) Complexes of Tridentate Indazolylpyridine Ligands: Enhanced Spin-Crossover Hysteresis and Ligand-Based Fluorescence

The Role of Coulomb Interactions for Spin Crossover Behaviors and Crystal Structural Transformation in Novel Anionic Fe(III) Complexes from a π-Extended ONO Ligand

Modulation of the ligand-based fluorescence of 3d metal complexes upon spin state change

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