Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F15/00—Compounds containing elements of Groups 8, 9, 10 or 18 of the Periodic Table
  • C07F15/02—Iron compounds
  • C07F15/025—Iron compounds without a metal-carbon linkage
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K9/00—Tenebrescent materials, i.e. materials for which the range of wavelengths for energy absorption is changed as a result of excitation by some form of energy
  • C09K9/02—Organic tenebrescent materials
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2211/00—Chemical nature of organic luminescent or tenebrescent compounds
  • C09K2211/18—Metal complexes
  • C09K2211/187—Metal complexes of the iron group metals, i.e. Fe, Co or Ni
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2991—Coated
  • Y10T428/2993—Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
  • Y10T428/2991—Coated
  • Y10T428/2993—Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
  • Y10T428/2995—Silane, siloxane or silicone coating

Definitions

• the present invention relates to a material consisting of particles having nanometric dimensions essentially comprising a spin transition compound, a process for the preparation of said material, as well as various applications of the material.
• Such compounds can in particular be coordination complexes containing one or more metal centers having a 3d 4 , 3d 6 or 3d 7 configuration, one or more nitrogenous ligands, and one or more anions, as described for example in EP-0 543 465, EP-O 666 561, EP-O 745 986 and EP-O 842 988.
• EP-O 543 465 describes a process for the preparation of spin transition compounds and the use for storing information.
• the process consists of bringing the ligand and an iron salt into an acid solution on the one hand, allowing it to react to obtain a precipitate, and recovering the precipitate from it in powder form.
• the complex obtained is previously reduced to powder, to be deposited on a support by various methods.
• the compounds mentioned correspond to one of the following formulas:
• EP-O 666 561 describes spin transition compounds, which correspond to the formula Fe (II) (H-TrZ) 3 (X) 2 in which Trz is 1, 2, 4-triazole, (X) 2 represents the anion (BF 4 " ) 2 , (ClO 4 " ) 2 , (Br “ ) 2f (Cl “ ) 2 or (CO 3 2 " ). These compounds have two crystalline phases each having spin transitions associated with a Color change
• EP-O 745 986 describes compounds corresponding to a formula analogous to that of the compounds of EP-O 543 465, in which M is a metal ion in configuration d5, d6 or d7, the ligand is a dialkylaminotriazole, the anion comprises a sulfitoaryl group, sulfitoalkyl, sulfito aryl or alkyl halide.
• M is a metal ion in configuration d5, d6 or d7
• the ligand is a dialkylaminotriazole
• the anion comprises a sulfitoaryl group, sulfitoalkyl, sulfito aryl or alkyl halide.
• These particular compounds have a hysteresis amplitude greater than 70 ° C, and a region of bistability centered exactly around room temperature. Said compounds are pink in the BS state and white in the HS state.
• EP-O 842 988 describes chemical compounds with spin transition and their use in display devices for exceeding the temperature threshold.
• the compounds are formed by a network consisting of molecules each formed by a metal-ligand complex and by an anion, and they comprise at least one molecule of water linked to the ligand by hydrogen bonding.
• the metal is chosen from those which have a configuration d4, d5, d6 or d7.
• the ligand is 1,2,4-triazole carrying a substituent R comprising an OH group.
• Anions are derivatives of tosylate and nitrate.
• the compounds meeting this definition have a temperature T1 / 2 ⁇ between 80 and 95 ° C. and T1 / 2J. from -17O 0 C.
• the compounds can be used in particular in devices intended to detect an accidentally high storage temperature (of the order of 8O 0 C) in storage buildings or transport vehicles.
• the compounds are prepared by mixing a precursor of the metal center and a precursor of the ligand, at ambient temperature, and removing the solvent by filtration after obtaining a precipitate.
• the compound is obtained in powder form.
• thermochromic pigments in polymer films having a micrometric thickness or as a data carrier in microsystems, the carriers having to remain transparent.
• the object of the present invention is to provide a process for the direct production of nanoparticles of iron complexes, of a triazole ligand and of at least one anion.
• the present invention therefore relates to a material in the form of nanoparticles of complexes, a process for obtaining said material, as well as applications of said material.
• the material according to the present invention consists of nanometric particles essentially comprising a compound corresponding to the formula
• - L represents a ligand 1, 2, 4-triazole carrying a substituent R on the nitrogen in position 4;
• X is an anion having the valence x, 1 ⁇ x ⁇ 2;
• - Y is an anion different from X having the valence x ', 1 ⁇ x' ⁇ 2;
• R is an alkyl group or a group R 1 R 2 N- in which R 1 and R 2 each independently of the other H or an alkyl radical;
• - M is a metal having a 3d 4 , 3d 5 , 3d 6 or 3d 7 configuration, other than Fe;
• nanometric particles particles which have an average diameter between 1 nm and 500 nm, more particularly between 1 and 100 nm. When w is 3, 300 or 1500 respectively, the average particle size is respectively about 1 nm, 100 nm or 500 nm.
• a compound that meets the above definition is capable of reversibly changing state of spin upon heating and cooling, with a color change associated with each change of spin.
• a substituent R is an alkyl group, it is preferably chosen from alkyl groups having from 1 to 8 carbon atoms, more particularly from 1 to 4 carbon atoms.
• R 1 and R 2 represent independently of each other preferably H or an alkyl group having from 1 to 8 carbon atoms, more particularly from 1 to 4 carbon atoms.
• Each of the anions X and Y can be a monovalent anion or a divalent anion.
• the monovalent anion is chosen from BF 4 " , ClO 4 " , Br “ , Cl “ and NO 3 " .
• the divalent anion is preferably chosen from SO 4 2" and CO 3 2 " .
• the choice of anions making it possible to control the spin transition (in particular the abrupt nature, the presence of hysteresis and the position of the transition).
• M plays the role of dopant of the spin transition phenomenon of the compound [(Fei-yMyL3) w Ii3] [X 2 / *] w .
• An increase in y decreases the abrupt nature of the transition and the intensity of the pink color corresponding to the low spin state.
• metal M mention may be made of the Zinc (II), Magnanese (II), Nickel (II), and Cobalt (II) ions.
• z ⁇ 0.
• the choice of the anions X and Y makes it possible to adjust the spin transition temperature and to play on the abrupt nature of the spin transition.
• the complex nanoparticles are coated with a silica film.
• the proposed material is obtained from a solution of Fe (II) salt and optionally a precursor of the metal M in a solvent or a mixture of solvents, and from a solution of ligand R-Trz in a solvent or a mixture of solvents.
• the preparation is carried out by a reverse micelle synthesis.
• the process includes the following steps:
• composition of the oil type with surfactant properties can be either a composition obtained by adding a surfactant to an oil, or a single product having both surfactant and oil properties (such as the products marketed under the names Lauropal ®, Tergitol ® or Ifralan ®).
• the size of the particles formed can be controlled in particular by the choice of the reaction temperature and / or the duration of contacting of the two microemulsions prepared respectively during steps a) and b). All other things being equal, an increase in duration and / or in temperature promotes an increase in the size of the final particles.
• the preparation is carried out by a microemulsion synthesis.
• the process includes the following steps:
• the proportions of solvent, surfactant and oil required to obtain a microemulsion are determined from the phase diagram of the ternary mixture.
• the ternary phase diagram is available in the literature for many solvent / oil / surfactant combinations. The determination of a particular ternary diagram is within the reach of the skilled person.
• an aqueous solution is prepared containing a Fe salt of one of the anions and a Fe salt of the other anion, before contacting with the "surfactant + oil" mixture;
• a solution is prepared containing at least one iron salt of one of the anions and at least one salt of M of the other anion.
• a silylated derivative is added to the reaction medium, before denaturation of the micelle or of the micro- emulsion
• silylated derivative mention may be made of tetraethoxysilane, n-octadecyl-triethoxysilane, and n-octyl-triethoxysilane.
• the material in the form of nanoparticles of the present invention is particularly useful as a thermochromic pigment.
• a varnish is often carried out in the form of a layer a few microns thick.
• the proposed nanoparticles can be incorporated directly into a polymer matrix which will be applied to a substrate in the form of a layer of micrometric thickness, while in the prior art, a preliminary step of grinding microparticles of spin transition material is necessary.
• Nanoparticles constitute a real "molecular memory” using the spin transition phenomenon. An information bit can thus be stored in each nanoparticle.
• the perfect transparency of a disk made up of a polymer matrix doped by these bistable nanoparticles makes it possible to envisage applications in the field of data storage in volume (holography).
• the significant change in color (i.e. of the absorption spectrum) associated with the spin transition phenomenon results in a change in the refractive index of the material between the low spin state and the high state spin.
• the respective refractive indices of the two states can be adapted to make the medium transparent when the molecules are in the HS state.
• the photo-induced effects can cause the switching from the HS state to the BS state, and therefore induce a variation in the refractive index.
• the initially transparent medium then becomes opaque. This phenomenon allows the use of nanoparticles in the field of optical limiters, as well as as an optical holder for data storage.
• Nanoparticles of a material whose magnetic response changes with temperature, from a diamagnetic form (BS state) to paramagnetic form (HS state), can be used for the development of heat-sensitive contrast agents for thermotherapy processes.
• the nanoparticles, placed in situ, would make it possible to follow the crossing of a temperature threshold, such as that which discriminates healthy cells from cancer cells.
• a temperature threshold such as that which discriminates healthy cells from cancer cells.
• the magnetic resonance image (MRI) of a medium containing the nanoparticles is normal in the case of nanoparticles in the low diamagnetic spin state and highly distorted in the case of a high paramagnetic spin state.
• a material was prepared by reverse emulsion synthesis according to the following operating mode.
• the compounds are dissolved by mechanical stirring, in a water bath at 50 ° C.
• Balloons A and B are then passed to the Vortex, which generates intense mechanical agitation favorable to the formation of micelles.
• the two reverse micelles thus obtained are thermodynamically stable for a few minutes.
• the contents of balloon B are quickly added to the contents of balloon A, then the whole is passed through the Vortex for a few minutes to promote micellar exchange.
• the particles are finally obtained by adding diethyl ether which has the effect of denaturing the reverse micelle. Diethyl ether solubilizes the surfactant and not the complex formed. After centrifugation and removal of the liquid phase, the washing operation is repeated 3 to 4 more times until the supernatant liquid is perfectly clear.
• Table 1 summarizes the specific conditions under which several samples were prepared.
• FIGS. 1, 2 and 3 represent TEM radiographs of the nanoparticles of complex [Fe (NH 2 trz) 3 ] (Br) 2 obtained in test No. 1.
• the radiographs in FIGS. 1 and 2 show a very regular structuring of the nanoparticles in spherical form. This structure results from the fact that the synthesis reaction is confined in nano-droplets.
• the particle size is of the order of 100 nm, which typically corresponds to a value of 300 for w in formula (I).
• Figure 3 highlights the transparency of a polymer doped with nanometric particles.
• a complex was prepared according to the method of the prior art, from the same precursors.
• the mixing of the precursors was carried out at room temperature, and the precipitate formed was separated by filtration.
• Figures 4, 5 and 6 show TEM shots of the precipitate obtained.
• Figures 4 and 5 show that spin transition particles synthesized by the process of the prior art do not have a regular structure. The grains are irregular and have a dimension of the order of 60 ⁇ m.
• Figure 6 shows the opacity generated by the introduction of micrometric particles (even in small proportions) in a structuring polymer (PVA type) originally transparent.
• PVA type structuring polymer
• a material was prepared by a microemulsion synthesis under the following conditions.
• the particles are finally obtained by adding ethanol which has the effect of denaturing the reverse microemulsion. Ethanol solubilizes the surfactant and not the complex formed. After centrifugation and removal of the liquid phase, the washing operation is repeated 3 to 4 times until the supernatant is perfectly clear.
• Nanoparticles were prepared from an Fe precursor and an M precursor by a synthesis in reverse emulsion under the conditions of test No. 3 given in Table 1, by introducing into the flask A 0.116 g of FeCl 2 and 0.124 g of ZnCl 2 instead of 0.21 g of FeCl 2 .
• the particle size is of the order of 100 nm, typically a w of 300.
• Example 2 The procedure of Example 2 was reproduced, replacing the FeBr 2 solution with a solution of FeCl 2 and ZnCl 2 .
• Example 2 was reproduced nanoparticles formed by the complex Fe 0, Zn 5 0, 5 Cl 2.
• the particle size is of the order of 100 nm, typically a w of 300.
• Example 1 The procedure of Example 1 was reproduced under the following conditions, by dissolving Fe (BF, j) 2 in the solution of Fe (NO 3 ) 2 .
• Nanoparticles of a complex [Fe (NH 2 TrZ) 3 (NO 3 ) i, 7 (BF 4 ) 0.3] were obtained.
• the particle size is of the order of 100 nm, typically a w of 300.
• Figure 7 shows the evolution of the reflectivity signal R as a function of temperature T for the complex of present example (curve b) and for the material of the same formula obtained in traditional synthesis (curve a).
• Example 1 A material was prepared with a coating of silica by a synthesis in reverse micelles according to the procedure of Example 1 implemented with the precursor FeBr 2 .
• the difference with Example 1 is that, after having mixed the two micellar solutions and stirred with Vortex for a few minutes, 2 ml of tetraethoxysilane (TEOS) have been added.
• TEOS tetraethoxysilane
• FIG. 8 shows the evolution of the reflectivity R as a function of the temperature T for the derivative Fe (NH 2 Trz) 3 (NO 3 ) 2 synthesized by the traditional route (a), by the reverse micellar route (b) (test n ° 2 of Table 1) and by reverse micellar route with coating of silica (c).
• Figure 9 shows the TEM image of a silica coating around a spin transition nanoparticle. This silica shell, of a few nanometers, results in a diffuse coating around the particle.
• a solution of mi g of FeBr 2 in 0.342 g of water was prepared, and a solution of 0.8 g of AOT in 23 ml of n-heptane, then the two solutions were mixed and the mixture was subjected. thus obtained by ultrasound until a clear solution, called solution A, is obtained.
• solution B A solution of m 2 g of NH 2 TrZ in 0.342 g of water was prepared, and a solution of 0.8 g of AOT in 23 ml of n-heptane, then the two solutions were mixed and the mixture thus obtained with ultrasound until a clear solution, called solution B, is obtained
• Figures 10a, b and c show the evolution of the magnetic signal, expressed as product X M T, respectively for samples 7 (1), 7 (2) and 7 (3).
• the molar magnetic susceptibility ⁇ M , in cm 3 mol "1 , multiplied by the temperature T, in degree K, is given on the ordinate and the temperature T, in degree K, is given on the abscissa, for the materials for which w 3 , 5 and 7.
• the curves confirm the presence of a gradual spin transition for the three nanomaterials around 300 K.
• FIG. 10 represents the structural formula of each of the materials constituting the samples 7 (1), 7 (2) and 7 (3).

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Compounds Of Iron (AREA)
• Manufacturing Of Micro-Capsules (AREA)
• Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)
• Luminescent Compositions (AREA)

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• 2005
  • 2005-12-08 FR FR0512476A patent/FR2894581B1/fr not_active Expired - Lifetime
• 2006
  • 2006-12-05 US US12/096,746 patent/US20080311401A1/en not_active Abandoned
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