Electrofluorochromic sheet, electrofluorochromic device, and metallosupramolecular polymer

Abstract

To provide a novel electrofluorochromic sheet containing a metallosupramolecular polymer.SOLUTION: An electrofluorochromic sheet includes a metallosupramolecular polymer formed by alternately connecting a cation of an element A selected from metal elements or lanthanoid elements and an organic ligand by a binding form containing at least one selected from the group consisting of a coordination bond and an organometallic bond, in which the organic ligand has, between cations, depending on the binding form, two or more coordination sites forming at least one luminous complex selected from the group consisting of the metal complex and an organometallic complex in one molecule, and has one or more redox response sites causing a redox reaction by application of a potential, the redox response site has at least one or more nitrogen atoms, and in the organic ligand, the coordination site and the redox response site are directly bonded or are bonded via a spacer site.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to an electrofluorochromic sheet, an electrofluorochromic device, and a metallosupramolecular polymer. [Background technology]

[0002] Electrofluorochromic materials, which can electrically induce reversible changes in fluorescence intensity, are known. These materials are expected to be used as fluorescent switching materials in optical memory devices, logic gates, bioimaging, sensors, and displays, and their development is currently underway.

[0003] As a material having such electrofluorochromic properties, Non-Patent Document 1 describes a polymer compound containing cyanoarylamine. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Chemical Communications, 2013, 49, pp. 9797-9799 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have been developing electrochromic sheets using metallo-supramolecular polymers formed by alternating organic ligands and (metal) cations, and electrochromic devices containing the same. However, they have not yet succeeded in completing an electrofluorochromic sheet using a metallo-supramolecular polymer.

[0006] Therefore, an object of the present invention is to provide a novel electrofluorochromic sheet containing a metallo-supramolecular polymer, and also to provide an electrofluorochromic device containing this electrofluorochromic sheet and the metallo-supramolecular polymer. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above object, the present inventors have found that the above object can be achieved by the following configuration.

[0008] [1] An electrofluorochromic sheet comprising a metallo-supramolecular polymer formed by alternating cations of at least one element A selected from the group consisting of metal elements of Groups 7 to 12 and lanthanoid elements with organic ligands via a bonding form including at least one selected from the group consisting of coordinate bonds and organometallic bonds, wherein the organic ligand has two or more coordination sites per molecule that form at least one luminescent complex selected from the group consisting of metal complexes and organometallic complexes via the bonding form with the cations, and has one or more redox-responsive sites that undergo an oxidation-reduction reaction upon application of an electric potential, and the redox-responsive site has at least one nitrogen atom, and the coordination site and the redox-responsive site in the organic ligand are bonded directly or via a spacer site. [2] The electrofluorochromic sheet according to [1], wherein the metal element is at least one selected from the group consisting of rhenium, ruthenium, osmium, rhodium, iridium, platinum, copper, silver, gold, zinc, and cadmium. [3] The electrofluorochromic sheet according to [1] or [2], wherein the lanthanoid element is at least one selected from the group consisting of praseodymium, neodymium, samarium, europium, gadolinium, and terbium. [4] The electrofluorochromic sheet according to any one of [1] to [3], wherein the coordination site includes at least one structure selected from the group consisting of a nitrogen-containing heterocycle and an aromatic ring capable of forming a metal-carbon bond. [5] The electrofluorochromic sheet according to any one of [1] to [4], wherein the redox responsive site comprises at least one structure selected from the structures represented by formulas 2A to 2C described below. [6] The electrofluorochromic sheet according to [5], wherein the redox responsive site comprises at least one structure selected from the group consisting of the structure represented by the above formula 2A and the structure represented by the above formula 2B. [7] The electrofluorochromic sheet according to any one of [1] to [6], wherein the spacer moiety comprises an arylene group having 6 to 20 carbon atoms which may contain a heteroatom. [8] The electrofluorochromic sheet according to any one of [1] to [7], wherein the metallo-supramolecular polymer contains one or more repeating units selected from the group consisting of formula 5AP, formula 5BP, formula 6AP, formula 6BP, formula 7AP, formula 7BP, formula 8AP, and formula 8BP described below. [9] The electrofluorochromic sheet according to any one of [1] to [8], wherein the spacer moiety is at least one divalent group selected from the group consisting of an alkynylene group having 2 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, a heteroarylene group having 6 to 20 carbon atoms, and a group formed by combining these groups.

[10] An electrofluorochromic sheet according to any one of [1] to [9], wherein the metallo-supramolecular polymer contains one or more of at least one trifunctional branching point selected from the group consisting of formulas 5CP, 6CP, 7CP, 8CP, and 9CP.

[11] An electrofluorochromic device comprising a pair of electrodes and the electrofluorochromic sheet according to any one of [1] to

[10] sandwiched between the electrodes.

[12] A metallo-supramolecular polymer comprising at least one repeating unit selected from the group consisting of formula 5AP, formula 5BP, formula 6AP, formula 6BP, formula 7AP, formula 7BP, formula 8AP, formula 8BP, formula 9AP, and formula 9BP, as described below.

[13] The metallo-supramolecular polymer according to

[12] further comprises at least one trifunctional branch point selected from the group consisting of formula 5CP, formula 6CP, formula 7CP, formula 8CP, and formula 9CP, which will be described later. [Effects of the Invention]

[0009] According to the present invention, there is provided a novel electrofluorochromic sheet containing a metallo-supramolecular polymer. Furthermore, according to the present invention, there are also provided an electrofluorochromic device containing this electrofluorochromic sheet, and a metallo-supramolecular polymer. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a configuration of an electrofluorochromic device according to an embodiment of the present invention. [Figure 2] This figure shows the change in the ultraviolet-visible absorption spectrum when a Zn(BF4)2 solution (MeOH, c=5×10-4 mol / L) is added to a CH2Cl2 solution (c=1×10-5 mol / L) containing an organic ligand (LTPA). [Figure 3] FIG. 1 is a graph showing the change in absorbance at 431 nm versus the metal / organic ligand molar ratio. [Figure 4] 1 is an absorption spectrum of a polyZn-EFC film (a specific example of the electrofluorochromic sheet according to the present invention) on an ITO (indium tin oxide) glass substrate. [Figure 5] 1 shows the emission spectrum of a polyZn-EFC film on an ITO glass substrate excited at 425 nm. [Figure 6] This shows the results of X-ray photoelectron spectroscopy (XPS) measurements of the polyZn-EFC film. [Figure 7]1 shows cyclic voltammograms of polyZn-EFC films. [Figure 8] FIG. 2 is a graph showing the change in luminescence intensity (excitation light=425 nm) when a potential of 0 to 1.6 V is applied to the working electrode of an electrofluorochromic device according to a specific embodiment of the present invention. [Figure 9] This figure compares an image (bottom) showing the quenched state when 1.6 V is applied to the working electrode of the electrofluorochromic device, and an image (top) showing the luminescent state when no potential is applied (0 V). [Figure 10] This figure shows the emission intensity at a wavelength of 650 nm measured when the fluorescence was repeatedly turned on and off by applying a potential. [Figure 11] This is the result of 1H NMR (Nuclear Magnetic Resonance, CD3OD) measurement of polyZn-EFC. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below. The following description of the components may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this specification, the term "C" is used to refer to a compound represented by a number after "C", for example, "C 10 " indicates that the number of carbon atoms is the number of the subscript. 10 " indicates that the number of carbon atoms is 10. This notation is "C 10 It is used like "alkyl group" and is synonymous with "alkyl group having 10 carbon atoms."

[0012] [Electrofluorochromic Devices] FIG. 1 is a cross-sectional view showing the configuration of an electrofluorochromic (hereinafter also referred to as "EFC") device according to an embodiment of the present invention. The EFC device 10 includes a pair of electrodes 15, an EFC sheet 13 sandwiched therebetween, and a solid electrolyte 12.

[0013] The pair of electrodes 15 includes a first electrode 11 and a second electrode 14, with the first electrode 11 in contact with the solid electrolyte 12 and the second electrode 14 in contact with the EFC sheet 13. The solid electrolyte 12 and the EFC sheet 13 are also in contact with each other.

[0014] The EFC device 10 has a pair of electrodes 15, and by applying a potential between these electrodes 15, the redox-responsive site (details of which will be described later) of the metallo-supramolecular polymer contained in the EFC sheet 13 undergoes an oxidation-reduction reaction, thereby exhibiting electrofluorochromic properties.

[0015] The material of the pair of electrodes 15 is not particularly limited, but from the viewpoint of facilitating application of the present EFC device to displays and the like, it is preferably light-transmitting. Examples of such materials include an SnO2 film, an In2O3 film, and an ITO (Indium Tin Oxide) film.

[0016] An active material layer may be further disposed on the surface of first electrode 11 facing solid electrolyte 12. EFC device 10 having an active material layer can switch the fluorescence ON / OFF with less power.

[0017] Examples of active materials include sodium iron phosphate, sodium cobalt oxide, sodium manganese bronze, copper hexacyanoferrate, and nickel hexacyanoferrate.

[0018] The material of the solid electrolyte 12 is not particularly limited, but typically, a composite containing a polymer compound, a supporting salt, and a plasticizer is preferred.

[0019] Examples of polymer compounds include, but are not limited to, polymethyl methacrylate (PMMA), polyethylene oxide (PEO), poly(vinylidene fluoride-co-hexafluoroisopropyl) (PVdF-co-PHFP), polypropylene carbonate (PPC), polycarbonate, and polyacrylonitrile.

[0020] The content of the polymer compound in the composite is not particularly limited, but is preferably 18 to 80% by mass when the total mass of the composite is taken as 100% by mass.

[0021] The supporting salt is not particularly limited, but examples thereof include LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, LiCF3COO, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), LiCH3COO, tetrabutylammonium perchlorate, tetraethylammonium perchlorate, KCl, NaClO3, NaCl, NaBF4, NaSCN, KBF4, Mg(ClO4)2, and Mg(BF4)2.

[0022] The content of the supporting salt in the composite is not particularly limited, but is preferably 1 to 15% by mass when the total mass of the composite is taken as 100% by mass.

[0023] Examples of the plasticizer include propylene carbonate (PC), ethylene carbonate, dimethyl carbonate, diethylene carbonate, γ-butyrolactone, succinonitrile, and ionic liquids.

[0024] The content of the plasticizer in the composite is not particularly limited, but is preferably 18 to 80% by mass when the total mass of the composite is taken as 100% by mass.

[0025] There are no particular limitations on the method for preparing the solid electrolyte 12, but after mixing the components, the mixture may be heated as needed. There are no particular limitations on the temperature at which the mixture may be heated, but examples include room temperature to 100°C. Although the present EFC device 10 includes a solid electrolyte 12 , the EFC device of the present invention does not necessarily have to include a solid electrolyte 12 .

[0026] There are no particular limitations on the method for manufacturing the EFC device of the present invention, but it is sufficient to laminate each layer in order on the first electrode 11 (or the second electrode 14).

[0027] The EFC sheet is a thin plate-like member that contains a metallo-supramolecular polymer, which will be described later, and whose fluorescence intensity changes reversibly when a potential is applied by a pair of electrodes 15 . The EFC sheet only needs to contain the metallo-supramolecular polymer described below, and may also contain other components. The content of the metallo-supramolecular polymer in the EFC sheet is not particularly limited, but is preferably 60% by mass or more, and more preferably 80% by mass or more, when the total mass of the EFC sheet is taken as 100% by mass. In one embodiment, the EFC sheet is preferably made of a metallo-supramolecular polymer.

[0028] The thickness of the EFC sheet may be adjusted as appropriate depending on the application of the EFC device, but when used as a display or light control panel, for example, a thickness of 10 nm to 10,000 μm is generally preferred.

[0029] When this EFC device is excited by irradiating it with light of a predetermined excitation wavelength in a state where no potential is applied to the second electrode 14, it emits light at a wavelength (color) that corresponds to the structure of the metallo-supramolecular polymer (the structure of the luminescent complex described below plays a major role). On the other hand, when a positive potential is applied to the second electrode 14, the emission intensity decreases according to the magnitude of the potential, and when a potential higher than the predetermined potential is applied, the emission is quenched. Furthermore, when the potential of the second electrode is brought closer to 0, the emission intensity increases again, and this process can be repeated.

[0030] In this case, the potential to be applied between the pair of electrodes 15 is not particularly limited, but is generally preferably 0 to 4.0V.

[0031] (Metallo-supramolecular polymer) Next, we will discuss in detail the metallo-supramolecular polymer contained in the EFC sheet.

[0032] The metallo-supramolecular polymer is formed by alternating cations of at least one element (hereinafter also referred to as "element A") selected from the group consisting of metal elements of Groups 7 to 12 and lanthanoid elements with organic ligands, via a bonding form including at least one selected from the group consisting of coordinate bonds and organometallic bonds, and the organic ligand has two or more coordination sites per molecule that form at least one luminescent complex selected from the group consisting of metal complexes and organometallic complexes through the above bonding form with the cation, and has one or more redox responsive sites that undergo an oxidation-reduction reaction upon application of an electric potential, and the redox responsive site has at least one or more nitrogen atoms, and in the organic ligand, the coordination site and the redox responsive site are bonded directly or via a spacer site.

[0033] Although the reason why the metallo-supramolecular polymer exhibits electrofluorochromic properties is not entirely clear, the present inventors speculate that the reason is as follows: Note that the following mechanism is merely speculation and is not a definitive explanation of the mechanism of action of the present invention.

[0034] The present inventors speculate that the electrofluorochromic properties of the metallo-supramolecular polymer are due to the following three factors.

[0035] (1) When an electric potential is applied, a redox reaction occurs, and radical cations are generated at the redox-responsive site, which quench the luminescence. (2) The absorption due to the n-π* transition of the organic ligand is reduced or eliminated by the generation of radical cations. This prevents the metallo-supramolecular polymer from reaching an excited state, making it difficult for light to be emitted. (3) Radical cations are generated at the redox-responsive site, resulting in new absorption and quenching of luminescence due to energy transfer.

[0036] The metallo-supramolecular polymer is formed by combining an organic ligand with a cation of element A. The organic ligand has two or more coordination sites and one or more redox-responsive sites, and the polymer is formed by repeated bonding between the coordination sites and the cation. The luminescent complex formed by the combination of the coordination site and the cation is bound to the redox-responsive site with or without a spacer site, and therefore can satisfy all of the above conditions (1) to (3), and it is presumed that the desired electrofluorochromic properties are obtained.

[0037] In the following, first, the cations and organic ligands that constitute the repeating units of the metallo-supramolecular polymer will be explained, and then the structure of the metallo-supramolecular polymer formed thereby will be described in detail.

[0038] (cation) The cation constituting the metallo-supramolecular polymer is a cation of at least one element A selected from the group consisting of metal elements of groups 7 to 12 and lanthanoid elements.

[0039] The metal element of Groups 7 to 12 is not particularly limited, and any known metal element can be used as long as it can form a luminescent complex in combination with the coordination site of the organic ligand described below. Examples of the metal element include Re, Ru, Os, Rh, Ir, Pt, Cu, Ag, Au, Zn, and Cd, and at least one selected from the group consisting of Ru, Ir, Pt, Zn, and Cd is preferred, and at least one selected from the group consisting of Ir, Pt, Zn, and Cd is more preferred.

[0040] In this specification, the term "luminescent complex" does not mean an independent compound such as the entire metallo-supramolecular polymer, but means a "metal complex" or "organometallic complex" formed by coordination bonding or organometallic bonding between multiple coordination sites and a cation of one element A, and incorporated as a part of the metallo-supramolecular polymer. In this specification, the "luminescent complex" is typically preferably a divalent group obtained by removing two hydrogen atoms from a general luminescent complex.

[0041] The selection of the "luminescent complex" in the metallo-supramolecular polymer can be determined based on whether the complex has a luminescent function in a general sense. That is, the "luminescent complex" incorporated as a part of the present metallo-supramolecular polymer is preferably a compound that itself has luminescence, and such compounds are known to those skilled in the art.

[0042] Similarly to the above-mentioned metal elements, the lanthanoid element is not particularly limited as long as it can form a luminescent complex with the coordination site of the organic ligand described below. Examples of such lanthanoid elements include praseodymium, neodymium, samarium, europium, gadolinium, and terbium, with europium and / or terbium being more preferred.

[0043] (organic ligand) The organic ligand has two or more coordination sites in one molecule that coordinate to a cation to form a luminescent complex, and one or more redox-responsive sites that initiate an oxidation-reduction reaction upon application of an electric potential. The coordination site and the redox-responsive site are bonded directly or via a spacer site.

[0044] Examples of bonding forms between organic ligands and cations include coordination bonding, in which a cation is bonded to nitrogen (N), oxygen (O), sulfur (S), or the like, and organometallic bonding, in which a cation is bonded to carbon. In this specification, a complex formed by coordinate bonds is called a metal complex, and a complex formed by organometallic bonds is called an organometallic complex.

[0045] Examples of luminescent complexes formed by such bonding forms include luminescent complexes represented by the following formulae Z1 to Z4: In the following formulae, * represents the spacer moiety or the bonding position with the redox-responsive moiety.

[0046] [ka]

[0047] The luminescent complex may be one in which the bond between the cation and the coordination site is formed by either a coordinate bond or an organometallic bond, as represented by formula Z1 and formula Z2. Alternatively, the luminescent complex may be one in which the bond is formed by both a coordinate bond and an organometallic bond, as represented by formula Z3. Alternatively, the luminescent complex may be one in which the bond is formed by a coordinate bond and / or an organometallic bond (hereinafter also referred to as a "coordinate bond, etc.") in addition to other bonds, as represented by formula Z4. In particular, the luminescent complex represented by formula Z4 is more stable and preferable when the central cation is a lanthanoid element including terbium. The four carboxy groups in the luminescent complex represented by formula Z4 form salts with the central Eu (europium) cation, and examples of such groups include hydroxy groups in addition to the above.

[0048] Metallo-supramolecular polymers are polymers formed by alternating cations and the above-mentioned organic ligands through coordination bonds, etc. Since the organic ligand has two or more coordination sites within the molecule, the unit structure is repeated by the bonds between these coordination sites and cations, forming a polymer compound.

[0049] The branching of the molecular chains of metallo-supramolecular polymers is influenced by the number of coordination sites of the organic ligands (described later) as well as the bonding form between the cation and the coordination site. When three or more coordination sites are coordinated to a cation, trifunctional or more branching points are formed.

[0050] In this regard, from the viewpoint of easily controlling the solvent solubility of the metallo-supramolecular polymer, a form in which the cation and the coordination site are coordinated at a molar ratio of 1:2 is preferred. For example, such a form may be one in which the coordination number of the cation is twice the number of coordination sites of the coordination site. Below, a form in which the cation and the coordination site are coordinated at a molar ratio of 1:2 will be described.

[0051] [ka]

[0052] The above formula 1 is an example of a preferred bonding form between a cation and a coordination site in a metallo-supramolecular polymer. In formula 1, M is a cation, Lig is a coordination site, and L 2 represents a single bond or -Sp-, Sp is a spacer moiety described later, and * represents the bonding position with the redox responsive moiety described later. In the above formula 1, Lig is bonded to M by a coordinate bond or the like, and Lig is covalently bonded to the redox responsive moiety or Sp. Note that the two Ligs may be the same or different, but are preferably the same, and the same applies to the case where there are two Sps.

[0053] The coordination site is not particularly limited as long as it can form a luminescent complex in relation to the cation. For example, a group having a nitrogen-containing heterocycle and an aromatic ring (e.g., a benzene ring) capable of forming a metal-carbon bond is preferred.

[0054] The group having a nitrogen-containing heterocycle is not particularly limited, and examples thereof include a 3- to 7-membered monocycle having a nitrogen atom, and a monovalent group obtained by removing one hydrogen atom from such a condensed ring (collectively referred to as a "nitrogen-containing coordination moiety"). The number of carbon atoms in the ring may be one or more.

[0055] Nitrogen-containing coordination sites include pyrrole, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, 1,2,3-triazole, 1,2,4-triazole, 1,3,4-thiadiazole, tetrazole, pyridine, pyrazine, pyrimidine, pyridazine, 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,4,5-tetrazine, azepine, azonine, quinoline, isoquinoline, acridine, phenanthridine, indole, isoindole, and carbazole. , benzimidazole, 1,8-naphthyridine, purine, pteridine, benzotriazole, quinoxaline, quinazoline, perimidine, cinnoline, phthalazine, 1,10-phenanthroline, phenoxazine, phenothiazine, phenazine, 8-hydroxyquinoline, 8-mercaptoquinoline, 2,2′-bipyridine, 2,2′-dipyridylamine, di(2-picolylamine), 2,2′,2″-terpyridine, porphyrin, phthalocyanine, and derivatives thereof, and monovalent groups in which one hydrogen atom has been removed.

[0056] In addition, the nitrogen-containing coordination site is preferably a monovalent group obtained by removing one hydrogen atom from pyrrole, imidazole, pyrazole, oxazole, thiazole, pyridine, or a derivative thereof, in order to provide a metallo-supramolecular polymer having a more excellent effect of the present invention.

[0057] Specific structures of nitrogen-containing coordination moieties are shown below. The nitrogen-containing coordination moiety is a monovalent group obtained by removing one of the optional hydrogen atoms contained in these compounds. An optional substituent may be bonded to the group. In the following formulae, p represents an integer of 2 or more and is not particularly limited, but is preferably 20 or less, more preferably 10 or less, and even more preferably 6 or less.

[0058] [ka]

[0059] [ka]

[0060] The precursor compound for forming the nitrogen-containing coordination site may be a commercially available product, or may be synthesized using a known method (e.g., C.H. Weidl, A.A. Precup, C. Eschbaumer, U.S. Schubert, Polymeric Materials: Science and Engineering, 84, 649 (2001)).

[0061] In addition to the above, the coordination site may also be a group having a hydroxy group, an alkoxy group, an acyl group, an alkoxy-carbonyl group, an acetylacetonato group, a benzylideneacetylacetonato group, a cycloalkadienyl group (such as a cyclopentadienyl group and a cyclooctadienyl group), a benzylidene group, a cyano group, a nitro group, an amino group, a phosphino group, or a combination thereof.

[0062] The organic ligand has two or more coordination sites in one molecule, and although there is no particular upper limit, it is preferably four or less, and more preferably three or less. The two or more coordination sites may be the same or different, but are preferably the same.

[0063] (Spacer part) The spacer moiety is a moiety that connects the coordination moiety and the redox-responsive moiety (described later) to form the main chain of the metallo-supramolecular polymer. The bonding form between the coordination site and the redox-responsive site is not particularly limited, but it is preferable that they are linked by a covalent bond.

[0064] The structure of the spacer portion is not particularly limited, but the portion adjacent to the redox responsive portion, i.e., the portion directly bonded to the redox responsive portion, may have C6 to C 20 an arylene group or a C6-C 20 It is preferable that the group has a heteroarylene group.

[0065] As will be described later, the redox-responsive site contains a nitrogen atom, and generates a radical cation by applying a (positive) potential. At this time, the part adjacent to the redox-responsive site has C6 to C 20 an arylene group or a C6-C 20 When a spacer moiety having a divalent aromatic hydrocarbon group such as a heteroarylene group is arranged, the radical cation generated by application of an electric potential is easily stabilized.

[0066] In electrofluorochromic sheets, it is preferable that the fluorescent OFF state induced by the application of a potential is as stable as possible. In addition, the ability to repeatedly switch ON / OFF is also an important characteristic.

[0067] In this regard, when the spacer moiety has an arylene group and / or a heteroarylene group and is directly bonded to the redox-responsive moiety, the resulting metallo-supramolecular polymer is more likely to stabilize the radical cation generated by application of an electric potential and to have better properties required for the application of electrofluorochromic materials.

[0068] The spacer moiety preferably has a function of connecting the coordination moiety and the redox-responsive moiety and also a function of transferring electrons within the organic ligand. For example, it is preferable that the spacer moiety is entirely or partially conjugated.

[0069] Examples of such spacer moieties include linear, branched, or cyclic C1 to C6 20 Alkylene group, C2-C 20 Alkenylene group, C2-C 20 Alkynylene group; C6-C 20 Arylene group; C6-C 20 Heteroarylene groups; groups combining these; and the like are preferred. Among these, the spacer moiety is preferably C2 to C5, in order to obtain an electrofluorochromic material having a more excellent effect of the present invention. 20 Alkynylene group, C6-C 20 Arylene group, C6-C 20 At least one divalent group selected from the group consisting of heteroarylene groups and groups formed by combining these groups is preferred.

[0070] An example of the spacer moiety is a group represented by the following formula 3AA: In formula 3AA, * represents the bonding position with the redox responsive moiety and the bonding position with the coordination moiety, respectively.

[0071] [ka]

[0072] (redox response site) The redox-responsive site refers to an atomic group that undergoes an oxidation-reduction reaction upon application of an electric potential. The organic ligand has at least one redox-responsive site per molecule. Although there is no upper limit, three or fewer sites are generally preferred. The oxidation-reduction reaction may result in the generation / disappearance of a radical cation.

[0073] The redox-responsive site contains at least one nitrogen atom, which has an unshared electron pair and generates a radical cation upon application of a (positive) potential. As already explained, it is speculated that the reversible generation and disappearance of stable radical cations inside the organic ligand molecules contributes to the achievement of fluorescence ON / OFF switching.

[0074] From the viewpoint of obtaining a metallo-supramolecular polymer having a more excellent effect of the present invention, the redox responsive site is preferably at least one structure selected from the structures represented by the following formulas 2A to 2C.

[0075] [ka]

[0076] In formula 2A, R 21 、 and R 22 are each independently a hydrogen atom or a C1 to C 20 represents a hydrocarbon group, and L 1 is divalent C1 to C 20 Represents a hydrocarbon group, and * indicates the bonding position with the spacer moiety.

[0077] The group represented by formula 2A is a side branch bonded to the spacer moiety constituting the main chain of the metallo-supramolecular polymer, and is a pendant group.

[0078] R 21 , and R 22 C1~C 20 The hydrocarbon group is a C1-C group which may have a heteroatom. 20 Alkyl groups, C2-C 20 Alkenyl groups and C2-C 20 alkynyl groups, and the like, all of which may be straight-chain, branched-chain, or cyclic.

[0079] Also, R 21 , and R 22 C1~C20 Other examples of hydrocarbon groups include C6-C 20 Aryl groups and C6 20 They may also be heteroaryl groups, or combinations of these with linear, branched, or cyclic alkyl, alkenyl, and alkynyl groups.

[0080] Among these, R is particularly advantageous in that it can further stabilize the radical cations generated by redox reactions. 21 , and R 22 is C6~C 20 Aryl groups and C6 20 It preferably contains a heteroaryl group. In addition, R 21 , and R 22 may be the same or different.

[0081] L 1 Divalent C1 to C 20 Examples of the hydrocarbon group include the divalent groups explained as specific examples of the spacer moiety, and the preferred embodiments are also the same.

[0082] [ka]

[0083] In formula 2B, R 23 is a hydrogen atom or C1-C 20 represents a hydrocarbon group, and * in Formula 2B and Formula 2C represents a bonding position with a coordination site or a spacer site.

[0084] The divalent group represented by formula 2B is bonded to two coordination sites, two spacer sites, or a coordination site and a spacer site, and is incorporated into the main chain of the metallo-supramolecular polymer. 23 is R 21 The same applies to the preferred embodiments.

[0085] The trivalent group represented by formula 2C is bonded to three moieties selected from the group consisting of a coordination moiety and a spacer moiety to form a trifunctional branch point.

[0086] When the redox responsive moiety consists solely of the structure represented by Formula 2A or Formula 2B, no branch points are usually generated from the redox responsive moiety. Furthermore, in the form in which the cation:coordination moiety is coordinated at a molar ratio of 1:2 as described above, branch points are usually unlikely to be generated from the luminescent complex moiety, and the resulting metallo-supramolecular polymer tends to be linear.

[0087] The reason why it is said that it is "likely" to become linear is that during the polymerization process of the metallo-supramolecular polymer, steric hindrance may occur, preventing the formation of coordinate bonds, etc., resulting in a disorder in the 1:2 coordinate bond, etc. (deteriorating the "structural regularity" described in JP 2018-145244 A), and in such cases, three coordination sites, which should normally bind to one cation, may bond, instead of two, and unintended branching points may occur.

[0088] However, when the redox-responsive moiety contains a structure represented by Formula 2A or Formula 2B, and the cation:coordination moiety is coordinated in a molar ratio of 1:2 as a rule, a metallo-supramolecular polymer having a repeating unit represented by Formula 3A or Formula 3B is typically obtained. Metallo-supramolecular polymers containing such repeating units have the excellent characteristics of being easily soluble in solvents and easily formed into films.

[0089] [ka]

[0090] In Formula 3A, Lig represents a coordination site, Sp represents a spacer site, M represents a cation of element A, CA represents a counter anion that compensates for the charge, and others (L 1 , R 21 , and R 22 ) have the same meanings as the respective symbols in formula 2A. In addition, in Formula 3B, Lig represents a coordination site, and L 2 represents a single bond or -Sp-, Sp represents a spacer moiety, M represents a cation of element A, CA represents a counter anion that compensates for the charge, and R 23 has the same meaning as the same symbol in formula 2B.

[0091] On the other hand, when the redox responsive moiety contains the structure represented by the above formula 2C, a trifunctional branch point is formed in the redox responsive moiety. A metallo-supramolecular polymer having such a structure has excellent mechanical strength.

[0092] Such a trifunctional branch point includes a structure represented by the following formula 3C when the cation:coordination site is coordinately bonded at a molar ratio of 1:2 in principle. In Formula 3C, Lig represents a coordination site, L 2 represents a single bond or -Sp-, Sp represents a spacer moiety, and M represents a cation of element A. In the formula, * represents the position of a coordinate bond with another organic ligand Lig.

[0093] [ka]

[0094] (Preferred form of organic ligand) Next, preferred forms of the organic ligand will be explained. Preferred forms of the organic ligand include compounds represented by formula 4A, formula 4B, and formula 4C.

[0095] [ka]

[0096] In the above formulas 4A to 4C, Lig represents a coordination site, and L 2 represents a single bond or -Sp-, where Sp represents a spacer moiety, and R 21 , R 22 , and R 23has the same meaning as each symbol in formulas 2A to 2C, and the preferred embodiments are also the same.

[0097] In particular, from the viewpoint of obtaining an electrofluorochromic sheet having a more excellent effect of the present invention, the organic ligand preferably contains a compound represented by 4B.

[0098] When the organic ligand contains a compound represented by the following formulae 5A to 5C, 6A to 6C, 7A to 7C, 8A to 8C, and 9A to 9C, the resulting electrofluorochromic sheet has better effects of the present invention. In particular, when the organic ligand contains one or more of the compounds represented by formulae 5A to 5C, 6A to 6C, 7A to 7C, and 8A to 8C, the electrofluorochromic sheet exhibits even more excellent effects of the present invention. When the organic ligand contains compounds represented by 5B, 6B, 7B, 8B, and 9B, the electrofluorochromic sheet has better effects of the present invention, and when it contains compounds represented by 5B, 6B, 7B, and 8B, the electrofluorochromic sheet has even better effects of the present invention.

[0099] [ka]

[0100] In formulas 5A to 5C, R 51 , R 52 , and R 53 each independently represents at least one atom or group selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and a plurality of R 51 , R 52 , and R 53 may be the same or different. 2 represents a single bond or -Sp-, where Sp represents a spacer moiety. 21 , R 22 , and R 23 has the same meaning as each symbol in formulas 2A to 2C, and the preferred embodiments are also the same.

[0101] R 51 , R 52 , and R 53 The alkyl group is not particularly limited, but may be a straight or branched C1-C 20 The aryl group includes alkyl groups of C6 to C 20 An example is an aryl group. More specifically, R 51 Examples of the alkyl group include a methyl group, an ethyl group, an n-butyl group, a t-butyl group, a phenyl group, and a toluyl group.

[0102] These aryl groups and alkyl groups may further have a substituent. Examples of such a substituent include alkyl groups such as methyl, ethyl, and hexyl groups, alkoxy groups such as methoxy and butoxy groups, and halogen groups such as chlorine and bromine.

[0103] [ka]

[0104] In formulas 6A to 6C, R 61 , R 62 , and R 63 represents at least one selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and a plurality of R 61 , R 62 , and R 63 may be the same or different, and a preferred embodiment is 51 is the same as: Also, L 2 represents a single bond or -Sp-, where Sp represents a spacer moiety. Also, R 21 , R 22 , and R 23 has the same meaning as each symbol in formulas 2A to 2C, and the preferred embodiments are also the same.

[0105] [ka]

[0106] In Formulas 7A to 7C, Sp represents a spacer moiety, R 71 , R 72 , and R 73 represents at least one selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and a plurality of R 71 , R 72 , and R 73 may be the same or different, and a preferred embodiment is 51 is the same as: Also, L 2 represents a single bond or -Sp-, where Sp represents a spacer moiety. Also, R 21 , R 22 , and R 23 has the same meaning as each symbol in formulas 2A to 2C, and the preferred embodiments are also the same.

[0107] [ka]

[0108] In Formulae 8A to 8C, Sp represents a spacer moiety, R 81 , R 82 , and R 83 represents at least one selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and a plurality of R 81 , R 82 , and R 83 may be the same or different, and a preferred embodiment is 51 is the same as: Also, L 2 represents a single bond or -Sp-, where Sp represents a spacer moiety. Also, R 21 , R 22 , and R 23 has the same meaning as each symbol in formulas 2A to 2C, and the preferred embodiments are also the same.

[0109] [ka]

[0110] In Formulae 9A to 9C, Sp represents a spacer moiety, R 91 , R 92 , and R 93 represents at least one selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and a plurality of R 91 , R 92 , and R 93 may be the same or different, and a preferred embodiment is 51 is the same as: Also, L 2 represents a single bond or -Sp-, where Sp represents a spacer moiety. Also, R 21 , R 22 , and R 23 has the same meaning as each symbol in formulas 2A to 2C, and the preferred embodiments are also the same.

[0111] The organic ligand can be synthesized by a known method. For example, ACS Appl. Mater. Interfaces 2020, 12, 58277-58286 and ACS Appl. Mater. Interfaces 2014, 6, 9118-9125 describe a method for obtaining an organic ligand by cross-coupling (Suzuki coupling) a precursor compound of a coordination site and a precursor compound of a redox-responsive site. Alternatively, the method described in paragraphs 0014 to 0085 of JP-A-2012-017265 can also be used.

[0112] [ka]

[0113] In the above formula, Pd(PPh3)4 is tetrakis(triphenylphosphine)palladium.

[0114] [ka]

[0115] In the above formula, Pd(PPh3Cl)2 represents dichlorobis(triphenylphosphine)palladium. Note that the above is an example of a method for synthesizing an organic ligand, and the method is not limited to the above, and any method known to those skilled in the art can be used as appropriate.

[0116] (Preferred form of metallo-supramolecular polymer) The metallo-supramolecular polymer according to the embodiment of the present invention is a polymer formed by alternately linking predetermined cations and organic ligands via coordinate bonds or the like, and preferably contains, for example, the following repeating units.

[0117] The following repeating units are formed by coordination bonding of an organic ligand and a cation in a molar ratio of 1:1 (coordination site:cation=2:1), and a metallo-supramolecular polymer consisting only of these repeating units is linear, and a metallo-supramolecular polymer containing these repeating units has a linear structure.

[0118] [ka]

[0119] Each symbol in formula 5AP and formula 5BP has the same meaning as each symbol in formula 5A and formula 5B, and the preferred embodiments are also the same. Furthermore, M represents a cation of the element A already explained, and the same applies to the following formulae.

[0120] The metallo-supramolecular polymer may contain a counter anion, and it is preferable that the charge of the metallo-supramolecular polymer as a whole is compensated.

[0121] Examples of counter anions include acetate ions, phosphate ions, chloride ions, phosphorus hexafluoride ions, boron tetrafluoride ions, perchlorate ions, triflate ions, polyoxometalates, and mixtures of these ions.

[0122] [ka]

[0123] Each symbol in formula 6AP and formula 6BP has the same meaning as each symbol in formula 6A and formula 6B, and the preferred embodiments are also the same.

[0124] [ka]

[0125] Each symbol in formula 7AP and formula 7BP has the same meaning as each symbol in formula 7A and formula 7B, and the preferred embodiments are also the same.

[0126] [ka]

[0127] Each symbol in formula 8AP and formula 8BP has the same meaning as each symbol in formula 8A and formula 8B, and the preferred embodiments are also the same.

[0128] [ka]

[0129] The symbols in formula 9AP and formula 9BP have the same meanings as the following symbols in formula 9A and formula 9B, and the preferred embodiments are also the same.

[0130] The metallo-supramolecular polymer may have a branching point derived from the structure of the organic ligand, and the branching point is preferably a trifunctional branching point. Examples of such trifunctional branching points include structures represented by the following formulas 5CP to 9CP.

[0131] [ka]

[0132] In formulae 5CP to 9CP, M represents a cation of a specific element, and the wavy line indicates that the following structure is omitted and typically represents the bonding position with the spacer moiety. The other symbols have the same meanings as the symbols in formulae 5C to 9C, and the preferred embodiments are also the same.

[0133] ·Method for synthesizing metallo-supramolecular polymers There are no particular limitations on the method for synthesizing the metallo-supramolecular polymer, but examples include a method in which a mixture containing an organic ligand and a salt of element A is prepared and heated. The mixture may further contain a solvent.

[0134] Examples of salts of element A include acetates, sulfates, carbonates, perchlorates, tetrafluoroborates, hexafluorophosphates, and chlorides. The content ratio of the organic ligand to the salt in the mixture is not particularly limited, but from the viewpoint of facilitating the reaction, the molar content ratio of the element A content to the organic ligand content in the mixture (element A / organic ligand) is preferably 0.5 to 1.5, more preferably 0.75 to 1.25.

[0135] It is preferable that the mixture contains at least one organic ligand selected from the group consisting of an organic ligand represented by formula 4A ("4A ligand"), an organic ligand represented by formula 4B ("4B ligand"), and an organic ligand represented by formula 4C ("4C ligand").

[0136] The content ratio of the 4A ligand, the 4B ligand, and the 4C ligand in the mixture is not particularly limited, but from the viewpoint of the resulting metallo-supramolecular polymer having better solubility in solvents and better mechanical strength, it is preferable that the content ratio of the molar content of the 4C ligand to the total molar content of the 4A ligand, the molar content of the 4B ligand, and the molar content of the 4C ligand in the mixture (4C / 4A+4B+4C) is 0.01 to 0.2.

[0137] The ratio of the organic ligands is appropriately changed depending on the properties required for the metallo-supramolecular polymer. For example, from the viewpoint of high solvent solubility and easy formation of an electrofluorochromic sheet, the metallo-supramolecular polymer preferably has excellent solubility in the solvent. In this case, the organic ligands contained in the mixture are preferably only 4A ligands and / or 4B ligands.

[0138] On the other hand, from the viewpoint of obtaining an electrofluorochromic sheet having excellent mechanical strength, it is preferable to contain a 4C ligand. In this case, the sheet can be formed, for example, by synthesis at a liquid phase interface. That is, an electrofluorochromic sheet can be obtained at a liquid phase interface by causing a polymerization reaction at the boundary between a solvent (immiscible with water) containing an organic ligand and an aqueous solution containing a cation.

[0139] As described above, the branched structure of the organic ligand can be appropriately changed depending on the properties required for the metallo-supramolecular polymer.

[0140] The solvent contained in the mixture is not particularly limited, but examples thereof include water, organic solvents, and mixtures thereof. The organic solvent is not particularly limited, but examples thereof include ethylene glycol, ethanol, methanol, chloroform, NMP (N-methyl-2-pyrrolidone), dimethylformamide, dichloromethane, and dimethyl sulfoxide.

[0141] The content of the solvent in the mixture is not particularly limited, but in general, the solid content in the mixture is preferably 0.0001 to 30% by mass. The reaction temperature is not particularly limited, but is preferably 60 to 140°C. The reaction time is not particularly limited, but is preferably 12 to 36 hours.

[0142] The method for heating the mixture is not particularly limited, but microwave heating as described in JP 2018-145244 A may be used. When microwave heating is used, the metallo-supramolecular polymer has better structural regularity.

[0143] Manufacturing method of electrofluorochromic sheet The electrofluorochromic sheet can be produced by preparing a metallo-supramolecular polymer solution, applying the resulting solution onto a substrate (eg, an electrode) to form a solution layer, and removing the solvent. Examples of such methods that can be applied include various coating methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, slit coating, capillary coating, spray coating, nozzle coating, gravure printing, screen printing, flexographic printing, offset printing, reverse printing, and inkjet printing. Alternatively, the electrofluorochromic sheet can be formed on a temporary support and then transferred onto the electrode.

[0144] The solvent contained in the solution is not particularly limited, but the same solvents as those already explained as organic solvents that can be used in the synthesis of metallo-supramolecular polymers can be used.

[0145] The thickness of the electrofluorochromic sheet is not particularly limited and may be adjusted appropriately depending on the application, but is generally preferably 10 nm to 1000 μm. [Example]

[0146] The present invention will be described in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the examples shown below.

[0147] [Organic ligand (L TPA ) synthesis] First, the organic ligand [4,4-bis(2,2:6,2-terpyridinyl)benzene]triphenylamine (L TPA ) was synthesized according to the following procedure.

[0148] 4,4'-DBTPA (465 mg, 1.15 mmol), terpyridine boronic acid ester (870 mg, 2 mmol), Pd(PPh3)4 (115 mg, ~10 mol%), and K2CO3 (1.38 g, 10 mmol) were added to DMSO (20 ml) and heated to reflux at 110 °C for 48 hours.

[0149] After cooling the reaction mixture to room temperature, the product was extracted with a mixture of CH2Cl2 / H2O. The pale yellow crude product was purified by column chromatography (basic alumina, CH2Cl2 / MeOH 95:5) to give 1.15 g (~70% yield) of L with an Rf of 0.85. TPA obtained.

[0150] L TPA The structure of 1 H-NMR, 13 The cations were determined by C-NMR and electrospray ionization mass spectrometry (ESI-MS) spectra.

[0151] 1 H-NMR:(400MHz, CD2Cl2)δ(ppm):8.81(s, 4H), 8.72-8.67(m, 8H), 7.98(d, J=8.7Hz, 4H), 7.90(td, J=7.5, 1.7Hz, 4 H), 7.77(d, J=17.6Hz, 4H), 7.62(d, J=8.2Hz, 4H), 7.38-7.30(m, 6H), 7.20(t, J=7.5Hz, 6H), 7.09(t, J=7.3Hz, 1H).

[0152] 13C-NMR:(CD2Cl2)δ:156.0, 155.9, 149.6, 149.1, 147.4, 141.3, 137.0, 136.8, 134. 4, 129.5, 128.9, 127.8, 127.7, 127.1, 125.0, 124.2, 124.0, 123.6, 121.2, 118.5.

[0153] ESI-TOF-MS (CHCl3 / MeOH, 1:1v / v)m / z:found 860.3(100%), 861.3(65%), 862.3(20%) for [M+H] + (calculated M:859.3 for C60H41N7).

[0154] [ka]

[0155] [Synthesis of Metallo-Supramolecular Polymers] Metallo-supramolecular polymers are composed of ligands (L TPA ) and Zn 2+ The metallo-supramolecular polymer was synthesized by complexing the ions in a 1:1 ratio. Hereafter, the synthesized metallo-supramolecular polymer is referred to as "polyZn-EFC."

[0156] First, place L in a two-neck round-bottom flask. TPA The mixture was refluxed with ethylene glycol for 24 hours. The bright orange-yellow reaction mixture was cooled to room temperature, and the ethylene glycol was completely removed under reduced pressure. The mixture was then washed 3-4 times with dichloromethane to remove unreacted ligands and red solids. Finally, the mixture was dried overnight in a vacuum to obtain the desired product as a pale yellow solid (yield: 95%). Figure 11 shows the structure of polyZn-EFC. 1 These are the results of H NMR (Nuclear Magnetic Resonance, CD3OD) measurements.

[0157] [ka]

[0158] [Preparation of metallo-supramolecular polymer sheets] The metallo-supramolecular polymer film was prepared by the following procedure. First, the solid polymer powder was dissolved in methanol to prepare a polyZn-EFC solution (concentration: 10 mg / ml). The solution was then filtered through a microsyringe filter (0.45 μm, polyvinylidene fluoride) to remove insoluble particles. Finally, the yellow solution was applied to an ITO glass substrate and a film was formed by spin coating. The resulting film was then dried in a vacuum oven (50 °C).

[0159] [Fabrication of electrofluorochromic devices] An electrofluorochromic device was fabricated using a sandwich structure consisting of polyZn-EFC-coated ITO glass as the working electrode, solid polymer gel as the electrolyte layer, and NiHCF (nickel hexacyanoferrate)-coated ITO glass as the counter electrode.

[0160] The electrolyte layer was synthesized by the following procedure. First, a transparent thin electrolyte gel film was prepared by mixing TBAP (tetrabutylammonium perchlorate), PC (propylene carbonate), and PMMA (polymethyl methacrylate, weight-average molecular weight: 350,000 (GPC)) in a ratio of 8 / 46 / 46 (w / w), and then heated between two glass substrates at 95°C and 40% relative humidity.

[0161] Next, the polyZn-EFC coated on the ITO-glass substrate was washed with 0.1M TBAP / CHCl solution to remove the low molecular weight portion of the polymer, and the working electrode was prepared. The counter electrode was an ITO-glass substrate coated with NiHCF and fabricated by spin coating.

[0162] The working electrode and counter electrode obtained as described above were sandwiched between transparent electrolyte gel membranes to form a sandwich structure.

[0163] [result] In polyZn-EFC, Zn 2+ The ion is L TPA It binds to the two terpyridine active sites (coordination sites) in a quasi-octahedral structure and accommodates two corresponding counter acetate ions ( - OAc) balances the charge of the polymer backbone.

[0164] Figure 2 shows the L TPA CHCl solution (c = 1 × 10 -5 mol / L) in Zn(BF4)2 solution (MeOH, c = 5 × 10 -4 The graph shows the change in the ultraviolet-visible absorption spectrum when HCl (mol / L) is added. TPA The double white line is the spectrum of L TPA / Zn 2+ The absorption spectrum is shown when the ions are in a 1:1 molar ratio. The spectra in between show the changes that occur with the addition of a methanol solution of Zn(BF4)2.

[0165] Solid L TPA According to the spectrum of the CH2Cl2 solution of * Transition and n-π * Two absorption peaks were observed at 279 nm and 368 nm, corresponding to the transitions, respectively. The solution was colorless.

[0166] When a methanol solution of Zn(BF4)2 was added to this, the intensities of both peaks gradually decreased, and at the same time, λ max Two new peaks appeared at 326 nm and 431 nm. These peaks were due to the TPA π-π * Transition and n-π * The intensity of this new peak is shifted to higher wavelengths compared to the peak of the transition, indicating that the coordination site (terpyridine) is coordinated to the metal cation. TPA Equimolar Zn 2+ It was saturated when ions were added (Figure 3). This result is L TPA and Zn 2+This suggests that the ions are complexed at a molar ratio of 1:1, that is, that a metallo-supramolecular polymer is formed at a molar ratio of 1:1.

[0167] FIG. 4 shows the absorption spectrum of the polyZn-EFC film on the ITO glass substrate, and FIG. 5 shows the emission spectrum of the polyZn-EFC film on the ITO glass substrate excited at 425 nm. As shown in Figure 4, the absorption spectrum of the polyZn-EFC film shows a π-π * Transitions and n-π * Two absorption peaks were observed at wavelengths of 326 nm and 430 nm, corresponding to the transitions, and the polyZn-EFC film was yellow in color.

[0168] Next, as shown in FIG. 5, when excited at 425 nm, a strong emission peak was observed at a wavelength of 587 nm, and bright orange fluorescence was obtained.

[0169] The results of X-ray photoelectron spectroscopy (XPS) of the polyZn-EFC film are shown in Figure 6. Using the wide-scan method, peaks corresponding to C1s, N1s, O1s, and Zn2p were observed at binding energies of 285, 400, 534, and 981 eV, respectively, suggesting that these are contained in the polymer skeleton. N(L) was qualitatively confirmed by considering the area under the curve (AUC) of N1s and Zn2p. TPA The atomic ratio of N1s (originating from N1s) to Zn (metal center) was 7.8:1, which is very close to the ideal value (N / Zn = 7:1). The area under the curve for N1s and Zn2p was also 7.8:1, which is very close to the ideal value (N / Zn = 7:1).

[0170] Furthermore, although the results are not shown, the thermal stability of the polymer evaluated by TGA (thermogravimetry) was good up to a temperature range of 550°C.

[0171] The electrochemical properties of polyZn-EFC were tested by three-electrode cyclic voltammetry (CV) at a scan speed of 20 mV / s in a non-aqueous (0.1 M TBAP / MeCN) electrolyte system. Figure 7 shows the cyclic voltammogram.

[0172] From the CV test, E° 1 / 2 =0.605V (vs. Ag / Ag + ) The excellent redox behavior of polyZn-EFC was clearly demonstrated. This oxidation-reduction characteristic shows that the forward oxidation peak is 0.69 V (vs. Ag / Ag + ), and the backward reduction peak is 0.52 V (vs. Ag / Ag + ), and triphenylamine (TPA) and its radical cation (TPA ·+ ) suggests a reversible change between

[0173] [ka]

[0174] An EFC device was fabricated by sandwiching a polyZn-EFC sheet and a transparent ion gel electrolyte layer between a pair of ITO-glass substrates. The fabricated device was excited by ultraviolet light and emitted reddish-orange fluorescence (λ max It emitted a vivid light (=680nm).

[0175] Figure 8 shows the effect of applied voltage on luminescence intensity (excited at 425 nm). In Figure 8, the open double line shows the luminescence intensity when the applied voltage is 0 V, and the solid line shows the luminescence intensity when the applied potential is 1.6 V. The line between these two lines shows the luminescence intensity when the applied potential is changed.

[0176] As shown in Figure 8, when a positive potential (1.6 V) is applied to the electrode in contact with the polyZn-EFC sheet, the fluorescence gradually decays and turns off. Figure 9 shows the corresponding ON / OFF state. Figure 10 shows the emission intensity at 650 nm when the switch is repeatedly turned ON / OFF (applied 0.0 V and 1.6 V). Figure 10 shows that the ON / OFF operation continues for several cycles, indicating good stability. [Industrial Applicability]

[0177] The redox-active ditopic ligand L TPA PolyZn-EFC was successfully synthesized by complexing with Zn(II) ions in a 1:1 molar ratio. The structure of this metallo-supramolecular polymer was confirmed by various spectroscopic and microscopic observations. In titration experiments using UV-visible absorption spectroscopy, the complexation of Zn(II) ions with L TPA The molar ratio of the complex formation was estimated to be 1:1. This result indicates that the complex formation of L, which has two tridentate terpyridine moieties, TPA By coordinating with the Zn(II) ion in a hexacoordinated structure, the Zn(II) ion and L TPA This indicates that the polymers are alternately connected and polymerized. polyZn-EFC has excellent processability, and a smooth, uniform polymer thin film was obtained by spin-coating a methanol solution of the polymer onto a conductive glass substrate (ITO glass). This polymer film appears yellow to the naked eye (absorption ~ 325 nm) and emits bright orange light under ultraviolet light (emission ~ 580 nm). Furthermore, when the redox behavior of the polyZn-EFC film was investigated by cyclic voltammetry measurements, it was found that the redox behavior of triphenylamine and the radical cation triphenylamine (TPA ⇔ TPA ·+ ) oxidation-reduction between E° 1 / 2 =0.6V(Ag / Ag + ) was confirmed to occur.

[0178] A solid-state electrofluorochromic device (EFC device) was fabricated by sandwiching a solid polymer ion gel film with ITO glass coated with polyZn-EFC as the working electrode and ITO glass coated with NiHCF as the counter electrode. The fabricated EFC device showed strong orange-red luminescence (emission ~ 650 nm) under normal conditions. When a positive potential (~ 1.6 V) was applied, the fluorescence rapidly disappeared and reappeared at 0.0 V. This luminescence ON / OFF was controlled by the TPA and TPA generated by applying an appropriate bias. ·+ The metallo-supramolecular polymer, in which the metal complex luminescence can be reversibly changed by the oxidation and reduction of the amine, is expected to lead to the development of EFC materials for displays. [Explanation of symbols]

[0179] 10: EFC device 11: 1st electrode 12: Solid electrolyte 13: EFC sheet 14:Second electrode 15: Electrode

Claims

1. a cation of at least one element selected from the group consisting of iridium, platinum, zinc, and cadmium, which are metal elements of Groups 7 to 12, and an organic ligand; An electrofluorochromic sheet comprising a metallo-supramolecular polymer formed by alternating bonding forms including at least one selected from the group consisting of coordinate bonds and organometallic bonds, the organic ligand has two or more coordination sites in one molecule that form, with the cation, at least one luminescent complex selected from the group consisting of a metal complex and an organometallic complex, depending on the bonding form; having one or more redox responsive sites that cause an oxidation-reduction reaction when an electric potential is applied; the redox responsive site has at least one nitrogen atom; In the organic ligand, the coordination site and the redox-responsive site are bonded directly or via a spacer site.

2. 2. The electrofluorochromic sheet according to claim 1, wherein the metal element is zinc.

3. The electrofluorochromic sheet according to claim 1 or 2, wherein the coordination site comprises at least one structure selected from the group consisting of a nitrogen-containing heterocycle and an aromatic ring capable of forming a metal-carbon bond.

4. The electrofluorochromic sheet according to any one of claims 1 to 3, wherein the redox responsive site comprises at least one structure selected from the structures represented by the following formulas 2A to 2C: 【Chemistry 1】 (In formula 1, R ２１ 、 and R ２２ each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms; L １ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, and * represents the bonding position with the spacer moiety. 【Chemistry 2】 (In formula 2B, R ２３ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and * in Formula 2B and Formula 2C represents the bonding position with the coordination moiety or the spacer moiety, respectively.

5. The electrofluorochromic sheet according to claim 4, wherein the redox responsive site comprises at least one structure selected from the group consisting of a structure represented by formula 2A and a structure represented by formula 2B.

6. 6. The electrofluorochromic sheet according to claim 1, wherein the spacer moiety comprises an arylene group having 6 to 20 carbon atoms which may contain a heteroatom.

7. The electrofluorochromic sheet according to any one of claims 1 to 6, wherein the metallo-supramolecular polymer contains one or more repeating units represented by the following formulas: 【Transformation 3】 【change】 【change】 【change】 (In each formula, R ５１ , R ５２ , R ６１ , R ６２ , R ７１ , R ７２ , R ８１ , and R ８２ each independently represents at least one atom or group selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and may be the same or different; L １ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, R ２１ 、 R ２２ , and R ２３ represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may be the same or different; L ２ represents a single bond or -Sp-, where Sp represents the spacer moiety, and M represents the cation.

8. The spacer moiety is at least one divalent group selected from the group consisting of an alkynylene group having 2 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, a heteroarylene group having 6 to 20 carbon atoms, and a group formed by combining these. The electrofluorochromic sheet according to any one of claims 1 to 7.

9. The electrofluorochromic sheet according to any one of claims 1 to 8, wherein the metallo-supramolecular polymer contains one or more of the trifunctional branch points represented by the following formula: 【Chemistry 4】 (In each formula, R ５３ , R ６３ , R ７３ , and R ８３ each independently represents at least one atom or group selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and may be the same or different; L ２ represents a single bond or -Sp-, Sp represents the spacer moiety, * represents the bonding position with the spacer moiety or the coordination moiety, and M represents the cation.

10. An electrofluorochromic device comprising a pair of electrodes and the electrofluorochromic sheet according to any one of claims 1 to 9 sandwiched between the electrodes.

11. A metallo-supramolecular polymer comprising one or more repeating units represented by the following formula: 【Transformation 5】 【change】 【change】 【change】 【change】 (In each formula, R ５１ , R ５２ , R ６１ , R ６２ , R ７１ , R ７２ , R ８１ , R ８２ , R ９１ , and R ９２ each independently represents at least one atom or group selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and may be the same or different; L １ represents a divalent hydrocarbon group having 1 to 20 carbon atoms, and R ２１ 、 R ２２ , and R ２３ represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may be the same or different; L ２ represents a single bond or -Sp-, Sp represents a spacer moiety, the spacer moiety is a divalent hydrocarbon group having 1 to 20 carbon atoms, and M represents a cation of at least one element selected from the group consisting of iridium, platinum, zinc, and cadmium, which are metal elements of Groups 7 to 12.

12. The metallo-supramolecular polymer according to claim 11, further comprising one or more of the trifunctional branch points represented by the following formula: 【Transformation 6】 (In each formula, R ５３ , R ６３ , R ７３ , R ８３ , and R ９３ each independently represents at least one atom or group selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group, and may be the same or different; M represents a cation of at least one element selected from the group consisting of iridium, platinum, zinc, and cadmium, which are metal elements of Groups 7 to 12; L ２ represents a single bond or -Sp-, Sp represents a spacer moiety, the spacer moiety represents a divalent hydrocarbon group having 1 to 20 carbon atoms, and * represents a bonding position.

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