Gels containing supramolecular nanotubes of single-chain magnets

Abstract

The present invention relates to a supramolecular nanotube comprising at least one single-chain magnet comprising a coordination polymer, said coordination polymer comprising at least one linear polymer chain comprising a repeat unit comprising at least one metal, said metal being coordinated by at least one ligand comprising at least one linear carbon chain, said linear carbon chain comprising 6 or more carbons, preferably, said linear carbon chain comprising 6-30 carbons.

Description

[Technical field]

[0001] The present invention relates to the field of single-chain magnets, more specifically to single-chain magnetic supramolecular nanotubes and to the preparation of single-chain magnetic supramolecular nanotubes in the form of supramolecular metallogels, and to the use of such supramolecular metallogels for information storage. [Background technology]

[0002] Supramolecular chemistry is a branch of chemistry based on non-covalent or weak interactions between atoms in a molecule or between molecules in a molecular assembly. Supramolecular gels are also defined as gels whose constituent molecules interact with each other by non-covalent bonds. Metal gels are materials that belong to the category of supramolecular gels that contain at least one metal. The preparation of such metal gels includes at least one coordination polymer that contains an organic moiety (ligand), consisting of one or more carbon chains or aromatic rings and that may contain heteroatoms (O, N, S, F, etc.), and one or more metal ions. Each metal ion establishes one or more coordination bonds with the ligand [Reference 1]. Metal ions and ligands may also impart physicochemical properties to the materials that are related to their intrinsic properties, such as luminescence, electrical conductivity, magnetism, etc. [References 2-5].

[0003] In addition, it is known to use elements from the f block of the periodic table, especially the lanthanides, to prepare supramolecular gels. These lanthanide-based gels are mainly used to obtain soft materials with luminescent features due to the characteristic optical properties of these ions of the 4f series [6-15].

[0004] However, the above-mentioned supramolecular gels prepared on the basis of lanthanide salts do not possess ideal magnetic or structural properties for their integration into information storage devices.

[0005] The use of supramolecular nanotubes as single-chain magnets with open magnetic hysteresis curves suitable for information storage applications is known [Reference 16], but in the state of the art these nanotubes are only available in crystalline form, in which case they are difficult or even impossible to deposit on surfaces. Summary of the Invention

[0006] The present invention relates to supramolecular materials that have ideal hysteresis curves for information storage, making them particularly easy to incorporate into information storage devices.

[0007] To this end, the present invention relates to a supramolecular nanotube comprising at least one single-chain magnet comprising a coordination polymer, said coordination polymer comprising at least one linear polymer chain comprising a repeating unit comprising at least one metal, said metal being coordinated by at least one ligand comprising at least one linear carbon chain comprising 6 or more carbons, i.e. linked via at least one coordinate bond, for example of ionic or covalent type, said linear carbon chain preferably comprising 6 to 30 carbons, said linear carbon chain advantageously comprising 9 to 27 carbons, or 12 to 24 carbons. The inventors have demonstrated, quite unexpectedly, that the presence of such linear carbon chains, due to their inherent properties as aliphatic chains, makes it possible to obtain precisely shaped nanotubes for the preparation of gels, in particular metal gels, which can be easily deposited on solid supports. The inventors have succeeded in preparing supramolecular materials in the form of gels and have demonstrated, entirely by chance, that unlike crystals, such supramolecular materials in the form of gels, in particular metallogel molecular materials, make it possible to deposit the supramolecular materials on solid surfaces for the purpose of producing information storage devices. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is an FT-IR spectrogram of the compound synthesized in the example. [Diagram 2]FIG. 2 shows the structural formulae obtained by X-ray diffraction of the three ligands used in the examples. [Diagram 3] FIG. 3 is an FT-IR spectrogram of the xerogel synthesized in the examples. [Figure 4] FIG. 4 shows the UV-visible spectrum at 70° C. of the compound synthesized in the example. [Diagram 5] FIG. 5 shows the UV-visible spectrum at 4° C. of the compound synthesized in the example. [Figure 6] FIG. 6 is an EPR spectrogram of the compound synthesized in the example. [Figure 7] FIG. 7 is an EPR spectrogram of the compound synthesized in the example. [Figure 8] FIG. 8 is an EPR spectrogram of the compound synthesized in the example. [Figure 9] FIG. 9 shows UV and EPR spectrograms of the compounds synthesized in the examples. [Figure 10] FIG. 10 is a graph showing the relationship between the static magnetic properties and temperature of the compounds synthesized in the examples, and the dependence of magnetization on the magnetic field. [Figure 11] FIG. 11 shows hysteresis curves of the compounds synthesized in the examples. [Figure 12] FIG. 12 is a graph showing the relationship between frequency and out-of-phase susceptibility of the compounds synthesized in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the context of the present invention, the term "nanotube", more specifically "supramolecular nanotube", refers to a tube having a diameter on the order of one nanometer formed by a helical arrangement of one-dimensional coordination polymers that interact with each other through weak bonds.

[0010] In the context of the present invention, the term "single-chain magnet" refers to a one-dimensional coordination polymer with magnetic properties confined within said coordination polymer. Single-chain magnets employ magnetic relaxation governed by the growth of the magnetic correlation length along the chain.

[0011] The term "coordination polymer" in the context of the present invention refers to inorganic or organometallic polymeric structures that contain metal centers interconnected by organic ligands. Coordination polymers can also be defined as coordination compounds having repeating coordination units, considered as metal-ligand type repeat units, that extend in one, two or three dimensions via coordinate bonds (IUPAC definition).

[0012] The term "metal" in the context of the present invention refers to either an uncharged metal atom, where the chemical element has an oxidation state of 0, or a negatively or positively charged metal ion, where the chemical element has an oxidation state other than 0.

[0013] The metal incorporated into the linear polymer chain is preferably a chemical element selected from the transition metal group.

[0014] The term "transition metals" refers to the lanthanides and actinides family of elements from the d block of the periodic table, as well as the elements from the f block of the periodic table. The inventors have shown that these chemical elements are the best candidates for the formation of supramolecular nanotubes according to the present invention.

[0015] Such supramolecular nanotubes allow the development of materials and processes suitable for the deposition of supramolecular materials in the form of nanotubes onto solid substrates. It is shown that the extension of the length allows to control the formation of the gel and thus promotes the formation of metal gels, especially in the presence of linear aliphatic solvents. Carbon chains, more specifically linear carbon chains, promote weak interactions between the chains in the supramolecular material through low energy bonds, for example by the formation of bonds that realize van der Waals interactions. The inventors have demonstrated, quite unexpectedly, that the length of the aliphatic carbon chain is a determining parameter for the formation of supramolecular nanotubes. Too small linear chains, incorporating less than 5 carbons, do not allow to obtain configurations in the form of nanotubes. Conversely, chains with 16 or more carbon atoms give access to the best formed nanotubes and to the production of metal gels with physicochemical properties compatible with their use for data storage (information storage). However, the use of chains of excessive length is undesirable, given that the steric hindrance is too great for interchain associations compatible with nanotube-type configurations.

[0016] Advantageously, the metal of the linear polymer chain is chosen from at least one of the 17 elements belonging to the rare earth group, namely Sc, Y, Lu, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb, preferably terbium Tb. The rare earth metals incorporated in the single chain magnet, and in particular terbium, have advantageous magnetic properties associated with a slow relaxation of the magnetization.

[0017] Advantageously, the supramolecular nanotube according to the invention comprises at least 7 single chain magnets, preferably the supramolecular nanotube comprises at least 10 single chain magnets. The inventors have demonstrated, entirely by chance, that the number of associated single chain magnets is a parameter of the highest order for controlling the obtaining of configurations of molecular assemblies in the form of nanotubes.

[0018] Advantageously, at least one ligand of the single chain magnet comprises a radical group. Such radical ligands advantageously have a radical on the nitrogen heteroatom, qualifying as N-radical ligands, or on the oxygen heteroatom, qualifying as O-radical ligands. Preferably, the radical ligands are O-radical ligands of nitroxide type, i.e. ligands in which part of the skeleton is a nitroxide represented by NO, which can be represented as follows: [ka] Such nitroxide-type radical ligands may be monodentate ligands, such as the TEMPO ligand [Reference 26], bidentate ligands, such as the 2pyNO ligand [Reference 27], or tridentate ligands, such as the 6pyNO ligand [Reference 28].

[0019] Preferably, the radical ligand comprises a nitronyl nitroxide radical, designated NIT, which has the following chemical formula: [ka]

[0020] Coordinating NIT ligands with metals, especially lanthanides, makes it possible to obtain magnetic relaxation curves with the properties expected for the applications sought in information storage [Ref. 25]. NITs also have the advantage of being able to finely control the formation of single-chain magnets [Refs. 17-19] that can assemble in a non-limiting manner to form cyclic assemblies, chains of larger dimensions, supramolecular nanotubes that form chiral helices [Ref. 16], and to link them opportunistically with chemical functional groups.

[0021] Advantageously, the ligands of the supramolecular nanotubes according to the invention comprise a linear carbon chain and an aromatic group substituted by a NIT radical, preferably the aromatic group being a phenoxy group (PhO-). The aromatic group takes part in non-covalent interactions of the π-stacking type, making it possible to stabilize the structure of the single-chain magnet by stacking of several groups in the same chain.

[0022] The present invention also relates to metal gels, including gels containing supramolecular nanotubes as presented above in the context of the present invention, the nanotubes containing molecules of a non-polar aprotic organic solvent, preferably a linear aliphatic solvent, the solvent being preferably selected from at least n-hexane, n-heptane, n-octane and n-decane, preferably n-heptane. n-heptane is preferred, which the inventors have fortuitously observed, making it possible to obtain identical gelation processes, in particular under the same conditions and at the same concentrations, for all metal gels studied, regardless of the length of the carbon chain of the ligand coordinated to the metal ion. The interaction of the linear carbon chain with the non-polar solvent molecules seems to further induce the formation of supramolecular nanotubes, i.e. the interaction between these various partners seems to more easily lead to the shaping of spaces in the form of nanotubes.

[0023] Preferably, the gel is obtained from a solution containing supramolecular nanotubes dissolved in a non-polar aprotic solvent, optionally with heating to obtain complete dissolution. The solution must then be cooled until it reaches a temperature of 0-5°C, maintaining this temperature for at least 1 minute, after which the mixture is allowed to return to room temperature.

[0024] The invention also relates to an information storage material comprising a substrate coated with a metal gel as previously described in the context of the invention. The substrate is preferably a silicon substrate. However, it may be any type of amorphous or crystalline, magnetic or non-magnetic, conductive or insulating material. Such a metal gel system deposited on a substrate makes it possible to achieve a significantly higher information storage capacity than that achieved in the prior art.

[0025] The invention also relates to a method for manufacturing an information storage material as previously described in the context of the invention, comprising a step of depositing a metal gel on a substrate by a spin-coating technique. Spin-coating involves depositing a solution of the substance of the film on the flat surface of a substrate rotating at high speed. This is a technique for forming a thin, uniform layer by applying a thin, uniform pressure to the substrate.

[0026] The manufacturing method according to the invention advantageously comprises the following steps: 1--thermally dissolving in a non-polar aprotic solvent the powder of single-chain magnet previously obtained by reaction between an organic ligand and a metal salt; 2- Depositing the mixture on a solid substrate by spin coating; 3- Cooling the mixture to a temperature of 0-5°C; 4- Allow the mixture to return to room temperature.

[0027] The present invention also relates to an information storage device comprising at least one of the elements selected from the following: at least one supramolecular nanotube as previously described in the context of the present invention, at least one metal gel as described above in the context of the present invention, and at least one information storage material as described above in the context of the present invention. EXAMPLES

[0028] The present invention is also described in the following detailed description using an experimental section detailing specific embodiments using examples, which are given for illustrative purposes only and should not be considered as limiting. Experimental part

[0029] Analytical grade solvents (such as methanol, chloroform, dichloromethane, and n-heptane) and aldehydes (4-hexyl-, 4-decyl-, and 4-octadecyloxybenzaldehyde) were commercially available and used without further purification.

[0030] Experimental Analysis and Protocol

[0031] FT-IR spectra were recorded on gels, solutions, and powders using a Perkin-Elmer® Frontier UATR™ spectrophotometer (4000-550 cm −1 , with a resolution of 1 cm −1 ).

[0032] UV-visible absorption spectra of solutions and gels were recorded using a Jasco®-V670 spectrophotometer in a Hellma® 110-QS cuvette with a 1 mm optical path (800–350 nm, 400 nm.min−1, with a resolution of 1 nm).

[0033] Elemental analyses (CHNS) were performed using a FlashEA 1112 series analyzer sold by Thermo Fischer Scientific®.

[0034] X-ray powder diffraction patterns were collected using a Panalytical® X'pert Pro™ diffractometer equipped with an X'Celerator® detector (45 kV, 40 mA, λ = 1.542 Å, mode θ / θ for CuKα). Simulated diagrams were calculated using the Mercury program from CCDC.

[0035] Fresh single crystals were mounted on a Bruker® diffractometer of the D8 Venture™ series equipped with a CMOS PHOTON 100™ detector. Crystal data were collected at 150 K using MoKα radiation (λ=0.70713 Å). The crystal structure was resolved by SHELXT1 and refined using a full-matrix least-squares method based on F2(SHELXL)2 running the WINGX3 program. All non-hydrogen atoms were Refined with anisotropic atomic displacement parameters, H atoms were finally included in their calculated positions and treated as spanning their parent atoms with constrained thermal parameters.

[0036] Gelling properties were evaluated by introducing the exact amount of target compound and the volume of solvent required to reach the required mass concentration. The flask was closed and heated with a heat gun until the compound was completely dissolved and the solution was homogenous. Depending on the gelation kinetics and concentration of the compound, the solution was cooled to 4°C for a few minutes or hours.

[0037] Magnetic studies were carried out using a SQUID (Superconducting Quantum Interference Device) type magnetometer of the MPMS series marketed by Quantum Design® equipped with an RSO probe. The ground powder of the precursor was pressed into a pellet to avoid orientation of the crystallites in the magnetic field. The new gel was transferred to a gelatin capsule and frozen at 100 K (the freezing point of n-heptane is 182 K) to avoid any additional decomposition. The powder measurements were corrected for diamagnetic contributions calculated using the Pascal constant, and the gel measurements were corrected by subtracting the diamagnetic contributions of the tube, Teflon®, fat, and solvent measured under the same conditions. The data were adjusted using MagSuite V.2.5™ software [Ref. 29].

[0038] Synthesis and gelation properties

[0039] Nitronyl-nitroxide radical (NIT) NITPhOC n Synthesis of ligands with (n=6, 10, 18) NITPhOC as described in the context of this specification n H 2n+1 The ligand is referred to as NITPhOC in the remainder of this specification. n Instead of specifying only the number of carbon atoms, n, in the linear carbon chain, the number of hydrogen atoms is specified without specifying it. NITPhOC6: 486 μL (2.5 mmol, 1 equiv.) of 4-(hexyloxy)benzaldehyde (CAS: 5736-94-7) is added to 741 mg (5 mmol, 2 equiv.) of 2,3-bis(hydroxyamino)-2,3-dimethylbutane in methanol (50 mL) and stirred at room temperature for 1 day. The solution is dried and the remaining milky white waxy solid is dissolved in 100 mL of CHCl and mixed with an aqueous solution (100 mL) of NaIO (641.6 mg, 3 mmol, 1.5 equiv.). The mixture immediately turns dark blue and the organic phase is washed several times with water (5 × 100 mL) and separated. The resulting solution is concentrated and purified by flash chromatography on a silica gel column (40–60 μm, 60 Å) eluted with a mixture of ether / n-pentane 3 / 1. The dark blue fractions are collected and concentrated under reduced pressure to give 149.1 mg (0.448 mmol) of a blue crystalline solid.

[0040] The same experimental protocol was 10 Synthesis of (from 4-(decyloxy)benzaldehyde - CAS: 24083-16-7) and NITPhOC 18 The synthesis of (from 4-(octadecyloxy)benzaldehyde - CAS: 4105-95-7) was closely reproduced, resulting in a deep blue crystalline powder and FT-IR signature similar to that obtained for NITPhOC6 [Reference 16]: see Figure 1. Figure 1 shows the transmittance on the Y-axis and the wavelength in cm on the X-axis. -1 A spectrogram of the cations in the NMR spectra is shown. Single crystals suitable for X-ray diffraction were obtained by slow layer diffusion of 7 mL of n-heptane onto a layer of 0.05 mmol of the radical in 10 mL of dichloromethane (DCM) and stored at 4 °C for several days.

[0041] NITPhOC 10 Or (2-(4'-(decyloxy)phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), yield: 36%. 23 H 37Calcined elemental analysis of N2O3 (%): C70.91, H9.57, N7.19. Measured values: C71.37, H9.59, N7.29.

[0042] NITPhOC 18 Or (2-(4'-(octadecyloxy)phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), yield: 25%. 31 H 53 Calcined elemental analysis of N2O3 (%): C 74.20, H 10.65, N 5.58. Measured values: C 74.55, H 10.51, N 5.54.

[0043] The crystallographic data are reported in [Table 1]. [Table 1] [Number 1] Formula for a:

number

number

[0044] FIG. 2 shows three ligands (NITPhOC6H) containing the nitronyl nitroxide radical (NIT) previously shown in the description of the diagram [Chemical 2]. 13 (Top), NITPhOC 10 H 21 (Middle), and NITPhOC 18 H 37 (bottom, thermal ellipsoid with 50% probability)) is shown after studying it by X-ray diffraction. As specified above, these ligands are designated without specifying the number of hydrogen atoms in the linear carbon chain, instead of specifying only the number of carbon atoms, n. n .

[0045] TbC n Synthesis of xerogels / precursors (n=6, 10, 18) In the context of the present invention, the compound of formula [Tb(hfac)3(NITPhOC n )] m The compounds represented by (n = 6, 10, 18) are [Tb(hfac)3 2H2O](hfac - = 1,1,1,5,5,5-hexafluoroacetylacetonate) and NITPhOC n In the context of the present invention, the three obtained coordination polymers [Tb(hfac)3(NITPhOC n )] m (n=6, 10, 18) are shown in a more simplified way, showing only the number of metal atoms and carbons in the linear chain of elemental subunits of the coordination polymer (TbC n (n=6, 10, 18). The index m is the number of basic units in the coordination polymer, with the value considered as infinite.

[0046] Dissolve 0.05 mmol (1 equiv.) of [Tb(hfac)3·2H2O] in 40 mL of boiling-dried n-heptane. Concentrate the solution until the volume reaches 10 mL, then cool to 75 °C. 0.05 mmol (1 equiv.) of NITPhOC n (n=6, 10, 18) was dissolved in 3 mL of CHCl3 and slowly added to the n-heptane solution, the mixture was allowed to warm to room temperature, and then evaporated under reduced pressure at room temperature to obtain TbC6 and TbC 10 Dark green powder for TbC 18 For 100% water, an elastic dark green solid is produced.

[0047] Deposition on solid surfaces: Silica substrates The formation of a thin gel film was performed in 99.9% ethanol (Si / Cz <100> n-doped, 2-5 Ωcm, Virginia Semiconductors™) on silica substrates cleaned by sonication in a solution of TbC6, TbC 10 , and TbC 18 The gel was formed by dissolving the powder formed under the conditions detailed above in n-heptane at a concentration of 2 mg / mL.

[0048] The flask was closed and heated with a heat gun until the compound was completely dissolved and the solution was homogenized. 10 μL of this homogenized solution was deposited and processed by spin-coating at 2000 rpm for 60 seconds. The new sample was then placed in a refrigerator at 4°C for 2 minutes to gel on the substrate, and then dried under a stream of dry N2. The resulting film is stable at room temperature.

[0049] Atomic force microscopy (AFM) studies were performed on thin films of gels on fresh substrates and mounted on AFM sample supports. Samples were measured in semi-contact mode using an SPM Solver P47 Pro (NT-MDT Spectrum Instrument™) and a HQ:NSC36 / Al BS silicon tip (cantilever B, 130 kHz, 2 N.m-1, MikroMasch™) to avoid degradation of the soft membrane. Results and images were processed with Gwyddion v2.56 software [Ref. 30].

[0050] Infrared spectroscopy analysis

[0051] Figure 3 shows the TbC n The FT-IR signatures obtained for three xerogels (n=6, 10, 18) are shown. The spectrograms are expressed as transmittance on the Y-axis and cm on the X-axis. -1 It should be read in wavelengths of units.

[0052] Analysis by UV-Visible Spectroscopy

[0053] Figures 4 and 5 are for n-heptane at a mass concentration of 10 mg / mL -1 The UV-visible spectra (normalized absorbance as a function of wavelength λ (nm)) of solutions of the three TbC n Complexes (n=6, 10, 18).

[0054] A significant color change is associated with a thermoreversible sol-gel transition from a deep blue solution to a translucent cyan gel, which was confirmed by UV-visible absorption measurements and is characterized by a 10-20 nm shift of the main absorption band to higher wavelengths, from 633-634 nm for the solution to 643-650 nm for the gel.

[0055] EPR analysis

[0056] Figures 6, 7 and 8 show EPR spectrograms (electron magnetic resonance, spectra represent normalized intensity on the Y-axis as a function of Landeg factor (dimensionless) on the X-axis) recorded on an Elexsys® E500 X-band CW X-band spectrometer.

[0057] [Table 2] shows the g values ​​for three terbium complexes. e Market price and a n Hyperfine binding values ​​are reported. [Table 2]

[0058] TbC 10 In FIG. 9 for the complex, UV (normalized absorbance as a function of wavelength λ in nm) and EPR (normalized intensity on the Y-axis as a function of the Lande g factor (dimensionless) on the X-axis) spectrograms are shown for both the 70° C. solution and the 4° C. gel on the same UV spectrum (left side).

[0059] Because nitroxide radicals are highly sensitive to EPR, they are used as spin markers to follow the assembly and gelation kinetics of modified organogels [Refs. 20-24].

[0060] TbC n The X-band EPR signal of the solution and gel was recorded at room temperature, giving a spectrum with five lines (due to hyperfine coupling between two equivalent nitrogen atoms). The factor g e and a n Value of (see figure and Table 3) agrees with the values ​​found in the literature for unbound / free NIT radicals. However, the strong decrease in the relative peak intensities between the spectra of the CHCl3 solution and the gel indicates a strong loss of free radical contribution / mobility due to the formation of the coordination network. It should be noted that only a small contribution of the uncoordinated (so-called free) NIT radicals was measured in the gel. This proves the good homogeneity of the gel and the good quality of the coordination between the metal ions and the NIT radicals.

[0061] Gelation The gelling properties were evaluated for various common solvents and are summarized in Table 3 below. 10 , and TbC 18 Minimum gelling concentration (MGC, mg.mL -1 The units are (S = soluble, I = insoluble). [Table 3]

[0062] Only linear aliphatic solvents allow effective gelation of the compounds, and the series TbC6, TbC 10 , TbC 18 The best gelling ability of is attributed to n-heptane. Among the solvents listed in Table 3, except for n-heptane, the solvents compete with the solubilization of the building blocks and / or the formation of coordinate bonds due to excess solvation, probably resulting in the formation of aromatic hfac - hinders the formation of a π-stacking pattern between TbC and the NIT phenyl fragment. n A low-temperature quenching step by placing the mixture containing the single-chain magnet in a refrigerator (4 °C and atmospheric pressure) is a necessary condition to form supramolecular nanotubes from the solution and thus obtain a gel. The gelling ability of the NIT radicals alone was tested in the same way, but they failed to produce a gel. This highlights the importance of the complexes with Tb(hfac)3 as "bonding nodes" between the organogelators during the self-aggregation process.

[0063] Static Magnetic Properties

[0064] Static magnetic properties (DC) are determined by the static magnetic field (H DC The product χ M The temperature dependence of T is 10 , and TbC 18 The behavior is similar between χ M The T(150K) values ​​are 12.28, 11.85, and 12.52 emu.K.mol -1 (emu, electromagnetic units). These values ​​are Theoretical χ for Tb(III) ion (J=6, gJ=3 / 2) and non-bonded radical (S=1 / 2, gS=2) M T value 12.195 emu.K.mol -1 By decreasing the temperature, these values ​​remain constant, then increase exponentially below 100 K, reaching 20.18 emu.K.mol at 5.5 K. -1 Maximum values ​​(TbC6) of 23.03 and 21.73 emu.K.mol at 4.5K -1 (respectively, TbC 10 and TbC 18 ) followed by a strong decrease due to the effects of saturation. This low-T exponential divergence is M T=C eff .exp(Δξ / kBT), and C eff is the effective Curie constant, k B This is a signature of the increasing correlation length along a single-chain magnet (SCM), where is the Boltzmann constant and Δξ is the correlation energy. Additionally, the dependence of the magnetization on the magnetic field is 5.2, 5.26, and 5.1 μB (for TbC6 and TbC6, respectively), starting from the weakest magnetic field, slightly smaller than the theoretical value of 5.5 μB, taking into account the ferrimagnetic and ferromagnetic interactions between the Tb(III) ions. 10 , and TbC 18 (about) the saturation value M sat Hysteresis measurements at low temperatures (0.5 K) show that TbC6, TbC 10 , and TbC18 The gel shows the existence of magnetic hysteresis and the coercive force H c are 3350, 2650 and 1570 Oe, respectively. The measurements obtained are reported in FIG. 10: (on the right) on the Y axis the magnetization M and μ B (Bohr magneton, 1N A μB=5,585cm3.Oe.mol-1, N A is Avogadro's constant), and the strength of the magnetic field H reported on the x-axis as a function of the unit kilo-o-stead (kOe), On the y-axis (left) is the product of molar sensitivity and temperature, χ M T is emu.K.mol -1 in units, as temperature dependence as a function of temperature in Kelvin (K) reported on the x-axis, In FIG. 11, on the Y-axis we have the strength of the magnetic field H reported in kilo-o-steads (kOe) and on the X-axis we have μ B The normalized magnetization M is shown as a function of

[0065] Dynamic Magnetic Properties

[0066] The magnetic relaxation behavior of the gel was measured under a static external magnetic field H DC In the absence of AC = 3 Oe). M ') and out-of-phase susceptibility (χ M " has a noisy but clear frequency dependence below 6 K. The measurements obtained are reported in FIG. 12 (where the frequency ν in Hz is shown on the X-axis and the out-of-phase susceptibility χ M " to emu.mol -1 (denoted by ).

[0067] The characteristic relaxation time τ is estimated using the generalized Debye model and follows the Arhhenius law τ = τ0.exp(Δ eff / k B T), where Δeff is the effective energy barrier. References

[0068] The following table lists the references cited earlier in the text. [Table 4-1] [Table 4-2]

Claims

1. 1. A supramolecular nanotube comprising at least one single-chain magnet comprising a coordination polymer, said coordination polymer comprising at least one linear polymer chain comprising a repeat unit comprising at least one metal, said metal being coordinated by at least one ligand comprising at least one linear carbon chain, said linear carbon chain comprising from 9 to 27 carbons.

2. The supramolecular nanotube of claim 1, wherein said linear carbon chain comprises 12 to 24 carbons.

3. 3. The supramolecular nanotube according to claim 1 or 2, wherein the metal of the linear polymer chain is a chemical element selected from the transition metal group.

4. 3. The supramolecular nanotube according to claim 1 or 2, wherein the metal of the linear polymer chain is selected from at least one of 17 elements belonging to the rare earth group, namely Sc, Y, Lu, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb.

5. The supramolecular nanotube of claim 1 or 2, wherein the supramolecular nanotube comprises at least seven single-chain magnets.

6. The supramolecular nanotube according to claim 1 or 2, wherein at least one ligand of said single chain magnet comprises a radical group, and preferably said ligand of said single chain magnet is a radical ligand selected from N-radical ligands and O-radical ligands.

7. 7. The supramolecular nanotube of claim 6, wherein the radical ligand comprises a nitronyl nitroxide radical, designated NIT.

8. 3. The supramolecular nanotube of claim 1 or 2, wherein said ligand comprises said linear carbon chain and an aromatic group substituted with a NIT radical.

9. 10. A metallogel comprising a gel comprising the supramolecular nanotubes of claim 1, wherein the nanotubes are dissolved in a non-polar aprotic organic solvent.

10. 10. The method for producing a metal gel according to claim 9, wherein the gel is obtained from a solution comprising the supramolecular nanotubes dissolved in the non-polar aprotic solvent, and cooled to reach a temperature of 0-5°C, and maintained at this temperature for at least 1 minute.

11. An information storage material comprising a substrate coated with the metal gel of claim 9.

12. 12. A method for manufacturing an information storage material according to claim 11, comprising the step of depositing the metal gel on the substrate by a spin coating method.

13. 1--thermally dissolving in a non-polar aprotic solvent a mixture containing a single-chain magnet previously obtained by reaction between an organic ligand and a metal salt; 2- Depositing said mixture on a solid substrate by spin coating; 3- Cooling the mixture to a temperature of 0-5°C; 4. The method of claim 12, further comprising the step of: allowing the mixture to cool to room temperature.

14. 3. An information storage device comprising at least one supramolecular nanotube according to claim 1 or 2.

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