Temperature integrity sensor

Abstract

The present invention relates to a temperature integrity sensor, or more accurately to a temperature continuity sensor of a product that needs to be maintained at a temperature below its degradation temperature, for example, the product is a refrigerated or frozen edible product; pharmaceutical products, such as vaccines or antibiotics; or a biomedical product, such as a sample of a bodily fluid or tissue, or organ. The sensor is based on the RFID technology, especially the passive RFID technology.

Description

Technical Field

[0001] The present invention relates to temperature integrity sensors, or more precisely, to temperature continuity sensors for products that need to be kept at a temperature below their degradation temperature, for example, the products are refrigerated or frozen edible products; pharmaceutical products, such as vaccines or antibiotics; or biomedical products, such as samples of body fluids or tissues, or organs.

[0002] The sensor is based on RFID technology, in particular passive RFID technology. Background Art

[0003] Temperature control in the cold chain (cold supply chain, CSC) is essential to ensure the quality, safety, hygiene and shelf life of perishable products. Medical products and food are two main areas where CSC can pose a hazard to the public if not properly controlled. Every year, pharmaceutical companies develop drugs and vaccines that require refrigeration to maintain their effectiveness. At the same time, perishable foods must be stored at temperatures below their "danger zone" to reduce the growth or spread of bacteria throughout the production and distribution chain (the production and distribution chain starts with the producer and ends with the consumer, often thousands of kilometers in between).

[0004] Current methods of monitoring temperature rely primarily on the use of data loggers and radio frequency identification (RFID) tags ( Figure 1 a). However, these devices only measure temperature at specific time intervals or when they are interrogated by a reader ( Figure 1 b), thus leaving no trace of any temperature changes that may have occurred during the interval between one measurement and another. More specifically, these sensors cannot monitor any changes in the cold chain, so products that have been exposed to temperatures outside of their optimal storage temperature and then returned to it will easily escape temperature control.

[0005] Therefore, failure to monitor the continuity of low temperatures can lead to serious problems affecting the integrity of sensitive products such as vaccines. Therefore, the development and implementation of a safe, reliable, easy-to-use low temperature continuity control system would represent a significant and unique technological advancement.

[0006] Today, tracking / monitoring of individual goods is often delegated to the application of RFID tags on the product packaging or the product itself.

[0007] Radio Frequency Identification tags are wireless devices with electronic circuits consisting of two basic components, an antenna that receives / analyzes signals and a memory microchip (tag) that stores an identification code. These devices communicate with an RFID reader to infer the identity of the object to which the tag is attached.

[0008] Tags can be either "active" or "passive." Active tags contain an onboard battery that powers the internal circuitry and generates radio waves. Passive tags have no battery and are powered directly by radio waves emitted by the RFID reader, which resonate with the antenna. Active and passive RFID tags designed for use as temperature sensors integrate components for real-time temperature detection in addition to conventional circuitry. The information acquired by this additional component is then transmitted to the reader ( Figure 1 b).

[0009] Passive RFID tags have attracted considerable attention in the development of organic-based wireless sensors. The simple architecture of the tag allows for the use of low-cost, highly sensitive and easy-to-use sensors for monitoring food spoilage, toxic substances and biomolecule screening. These devices are typically prepared by contacting a thin film of electron-rich (p-type) or electron-poor (n-type) organic semiconductors (π-conjugated organic compounds) with the metal circuit of the passive RFID. The organic layer at the heterojunction (the contact surface between the thin film and the metal of the RFID) acts as a signal "modulator" of the device, changing some of the inherent physical properties of the RFID circuit, such as frequency, impedance (Z) and reflection coefficient (S11). Any change in the organic semiconductor π system will result in a change in the physical properties of the RFID device, which can be recorded as a change in its radio frequency.

[0010] Structural changes in the π system of an organic semiconductor determine the modulation of its conductivity. These changes are usually obtained in two ways: by chemical reactions with specific analytes (chemical species, biological entities, etc.), and by changes in the geometric conformation of the π system. As mentioned above, the first method is usually used to prepare chemical sensors that can be successfully coupled to RFID devices for wireless reading of analytical results. These sensors are based on chemical transformations of the π system, which are caused by the reaction of the analyte with the molecules or polymers that constitute the organic layer. The second method is mainly used to prepare colorimetric (non-RFID) thermal sensors, which utilize changes in the optical activity (e.g., absorption spectrum, emission spectrum) of organic semiconductors in liquid media.

[0011] The latter type of sensor exploits the geometric changes of π conjugation, which are caused by the different rotational freedoms of the molecule at different temperatures. Here, high temperatures favor rotations along the σ molecular bonds of the π-conjugated system, allowing the formation of a distorted geometric configuration in which the aromatic subunits of the π-conjugated system are not located in the same conjugated plane. The σ molecular bonds in which two aromatic subunits are outside the conjugated plane (relative to each other) are "nodes". This node is a point where the electron delocalization (conjugation) is interrupted or significantly reduced. Therefore, in a distorted π-conjugated system, the effective conjugation of the molecule is limited by the planar molecular chain segments contained between the two nodes, rather than by the total number of aromatic subunits of the conjugated molecule. Therefore, the conjugated system at high temperature usually presents a conjugation-restricted conformation and therefore has a localized optical activity near the UV spectrum. In contrast, low temperatures suppress the rotation along the σ molecular bonds of the π-conjugated system and favor the planarization of the π-conjugated system, resulting in the delocalization of electrons along the entire conjugation, which leads to the optical activity being concentrated in the visible spectral range. In this type of sensor, the change between the optical activities leads to a consequent color change.

[0012] As stated above, to the best of our knowledge, RFID devices do not have the capability to measure temperature and store that information except at the expense of complex circuitry (e.g., batteries, thermocouples, memory) which would make the same device larger, heavier, more expensive, and less suitable for use as a monitoring "tag" for a single unit, even if the product to be monitored / controlled is small in the first place.

[0013] Meanwhile, organic semiconductors used in RFID devices, as an alternative to complex circuits, can only measure changes caused by chemical reactions in real time, and therefore are mainly capable of developing chemical and biological sensors.

[0014] Therefore, to date, there has not been:

[0015] - Passive RFID devices capable of measuring temperature or its changes and storing the information (thus with reduced circuitry);

[0016] -Organic semiconductors can be used as cold chain thermal sensors in RFID devices, which can measure temperature changes and store their time track.

[0017] Semiconducting organic compounds based on an architecture known as "Photochromic Torsional Switch" (PTS) are known and described in patent US10144744, which allows said π-conjugated organic compounds to modulate their optical and electronic properties by light stimulation. These materials are designed to undergo conformational changes of their π-conjugated systems by photoisomerization of "molecular actuators" inserted along the conjugated stretches ( Figure 2). Using this approach, the material has a low conductivity in its initial conformation (distorted / interrupted π-conjugated system) and a high conductivity after exposure to light (planarized π-conjugated system). The first conformation (distorted / poorly conductive conjugation) can also be spontaneously obtained from the second conformation (planarized / conductive π-conjugated system) by thermal relaxation, because the geometric configuration assumed by the PTS molecular actuator in the first conformation is energetically more stable than the geometric configuration assumed in the second conformation. This thermal relaxation process is slowed down (or prevented) at temperatures around 0°C and accelerated at temperatures above ambient temperature (~20°C). In the patent, it is mentioned that organic compounds based on the PTS architecture can be used as semiconductors in the active layer of organic optoelectronic devices, such as organic light-emitting diodes (OLEDs), organic solar cells (OSCs), and organic field-effect transistors (OFETs). However, the possibility of using thermal relaxation of PTS compounds to monitor temperature changes has never been discussed.

[0018] As a solution to the above technical limitations and problems, the present invention proposes to use a new class of organic semiconductors (described in US10144744) as active materials in conjunction with passive RFID devices.

[0019] Unless explicitly excluded in the following detailed description, the contents described in this chapter shall be considered as part of the detailed description of the present invention. Summary of the invention

[0020] It would be highly desirable to have an apparatus that implements an accurate, convenient, and low-cost method for assessing the temperature integrity status of perishable products to avoid product spoilage when the product's optimal storage temperature is not maintained.

[0021] Therefore, the object of the present invention is to develop an electronic device that is or includes a temperature integrity sensor based on RFID technology, especially based on passive RFID technology, which temperature integrity sensor includes one or several compounds selected from those described in the general formula of US10144744 as active materials bonded to the RFID.

[0022] Another object of the present invention is to develop a temperature integrity sensor based on RFID technology, in particular based on passive RFID technology, comprising a substrate and at least one layer on said substrate, the layer comprising at least one of the above-mentioned compounds.

[0023] Another object of the present invention is to develop a temperature integrity sensor based on RFID technology, especially based on passive RFID technology, which temperature integrity sensor includes an oligomer or polymer, which includes one or more PTS units and one or more residues selected from the general formula of US10144744.

[0024] Another object of the present invention is to develop a composition comprising one or more compounds selected from the group consisting of compounds described in the general formula of US10144744 and a carrier (e.g., toluene, tetrahydrofuran, chlorobenzene, chloroform, 2-methyl-tetrahydrofuran, 1,2,4-trimethylbenzene, 1,2,4-trichlorobenzene, o-xylene, anisole, 1,2-dichlorobenzene, methanol, water, isopropanol, acetone, ethyl acetate, cyclopentyl methyl ether); and / or additives (e.g., 1,4-diiodobutane, 1,6-diiodohexane, hexadecane, 4-bromoanisole, nitrobenzene, 1-methyl-2-pyrrolidone, diphenyl ether, cyclopentyl methyl ether, 1-methylnaphthalene, 1-chloronaphthalene, diethylene glycol dibutyl ether, polydimethylsiloxane).

[0025] The composition can be applied to the surface of an RFID tag or can be applied to the surface of an RFID tag or to the surface to which the RFID tag is applied. The application can be carried out by conventional methods known per se, selected from the group consisting of: brush coating, dip coating, spin coating, drop casting, doctor blading, knife coating, rod coating, spray coating, Langmuir-Blodgett deposition and slot die coating, all of which methods are known per se.

[0026] Another object of the present invention is to develop an electronic device or a component thereof, which comprises or is a radio frequency identification tag (RFID), preferably a passive RFID.

[0027] Another object of the present invention is the use of one or more compounds selected from those described in the general formula of US10144744 or a composition comprising said one or more compounds applied to an RFID tag for measuring the temperature integrity of a product.

[0028] Another object of the invention is the use as described above in a method for identifying and managing the perishability of products which, due to their perishability, must be stored at temperatures below their degradation temperature (e.g. room temperature) and whose perishability is related to exposure to temperatures above said degradation temperature for a period of time, which is related to their perishability at this higher temperature.

[0029] Another object of the present invention is a product or product packaging, on which a radio frequency identification tag is applied, the tag comprising one or more compounds selected from those described in claim 1 as active material that binds to the RFID.

[0030] Another object of the invention is to develop a method implemented by a computer or mobile device (scanner, mobile phone, PDA, smartphone, tablet, laptop), wherein the method is implemented by a processor and comprises the following stages:

[0031] i) Get the sensor operating value

[0032] ii) Obtain the control value and threshold of the product

[0033] iii) Obtain sensor signals

[0034] iv) Evaluate the level of thermal relaxation progression

[0035] v) Measurement count and history

[0036] vi) Health level of the allocated product.

[0037] Other objects of the invention are to develop a computer program comprising a code capable of performing, when executed on a computer, the steps i) to vi) defined in the present description and claims, as well as to develop a computer support comprising such a program.

[0038] According to the following specific embodiments and the accompanying drawings, other purposes, features and advantages of the present invention will become apparent. It should be understood that the specific embodiments and specific examples, although indicating preferred embodiments of the present invention, are provided for illustrative purposes only, because according to the following specific embodiments, changes and modifications in the spirit and scope of the present invention will become apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to better understand the various embodiments described herein, and to more clearly show how these various embodiments are implemented, reference will be made to the accompanying drawings which show at least one exemplary embodiment by way of example. The accompanying drawings are explanations of the embodiments exemplified herein and are not intended to limit the scope of the invention as determined by the claims.

[0040] Figure 1 Schematically shown are a first and a second embodiment of an RFID tag (a), and a corresponding possible RFID reader that can be used to implement the invention: a smartphone and an RFID reader (b).

[0041] Figure 2The molecular structure of the "Photochromic Twist Switch (PTS)" architecture is schematically shown.

[0042] Figure 3 The synthesis of the PTS unit which is not described in Chem. Sci. 2017, 8, 361-365 and patent US10144744 is schematically shown.

[0043] Figure 4 The synthetic method for functionalization of the PTS unit is schematically shown.

[0044] Figure 5 General synthetic methods for synthesizing preferred compounds of the invention are schematically shown and detailed syntheses are in the Examples section.

[0045] Figure 6 Analysis of planar / cis to non-planar / trans (or conducting to non-conducting) switching times (thermal relaxation) by UV-Vis absorption spectroscopy is shown. For example, the spectrum of PTS quaterthiophene (compound 6) is reported in (a) and the spectrum of PTS sexithiophene (compound 7) is reported in (b).

[0046] Figure 7 Other exemplary and non-limiting embodiments of RFID tags according to the present invention are schematically shown. (a) Depositing a coating containing PTS on the entire antenna (front view and top view); (b) Depositing a coating containing PTS on a portion of the antenna (front view and top view); (c) Depositing a coating containing PTS that connects a microchip to the antenna (front view and top view).

[0047] Figure 8 A block diagram showing the steps of the method of operation of the software according to the present invention.

[0048] Fig. 9 The monitoring of the radio signal change of the temperature integrity sensor according to the present invention is shown. Sexithiophene PTS (Compound 7) is representatively shown. (a) Signal at 0°C: 1) Untreated RFID (25°C); 2) RFID completely coated with non-activated PTS material (25°C); 3) RFID with activated PTS material (25°C, time 0); 4-7) RFID with activated PTS material (0°C, time 24h, 48h, 72h and 96h respectively). (b) Signal at room temperature (25°C): 1) Untreated RFID; 2) RFID completely coated with PTS material; 3) RFID with activated PTS material (time 0); 4) RFID with PTS material that switched from conductive to non-conductive (time 12h); 5) RFID with PTS material that switched from conductive to non-conductive (time 24h).

[0049] Fig.10 A table showing preferred PTS compounds. DETAILED DESCRIPTION

[0050] In the context of the present invention, the following definitions are given:

[0051] - The term "thermo-responsive" as used herein refers to a product or compound that responds to changes in temperature by adjusting its chemical-physical properties without deteriorating.

[0052] -The term “temperature integrity” refers to the continuity and consistency of temperature over a given time interval that ensures the integrity of products transported through the cold chain.

[0053] - The terms “temperature integrity sensor” and “temperature integrity seal” refer to devices that check the continuity and consistency of temperature over a given time interval to guarantee the integrity of products transported through the cold chain.

[0054] - The term "molecular actuator" refers to a "molecule" or "part of a molecule" that converts an external stimulus (such as light) into mechanical motion at the molecular level (such as twisting and / or rotation along molecular bonds), which in turn leads to changes in more complex molecular systems.

[0055] - The term "molecular switch" refers to a "molecule" or "part of a molecule" that is able to change its isomeric state in a reversible manner in response to an external stimulus, such as light.

[0056] -The term "π-conjugated system" refers to a p-orbital system arranged in the same plane as the delocalized electrons. The conjugated system consists of alternating single and multiple bonds.

[0057] - The term "monomer" refers to a "molecule" having functional groups that allow it to combine several times with other molecules to form macromolecules, oligomers or polymers.

[0058] - The term "oligomer" refers to a polymer formed from a limited number of monomers, which may be from 2 to 10 units.

[0059] - The term "polymer" refers to a macromolecule of high molecular weight formed from a large number of monomers, which may be from 11 to 1000 units.

[0060] - The term "subunit" or "aromatic subunit" refers to the aromatic ring that makes up the monomer, for example bithiophene as a monomer will contain two thiophene subunits and fluorene as a monomer consists of two phenyl subunits.

[0061] - The term "PTS unit" means a monomer consisting of a bithiophene unit and an azobenzene unit, wherein two thiophene subunits are attached to both ends of the azobenzene: one via a direct bond and the other via a carbon chain.

[0062] - The term "PTS compound" refers to a molecule, oligomer or polymer containing at least one PTS unit in its structure. Therefore, PTS compounds are mainly photosensitive semiconductors. Such PTS compounds may also be referred to as "π-conjugated compounds responsive to light and temperature", referred to herein as "thermoresponsive compounds".

[0063] - The terms "activated" and "non-activated" material refer to a solid material consisting of a PTS compound or a mixture thereof with additives, which has been irradiated with a wavelength of about 360 nm (activated) or has not been exposed to light (non-activated).

[0064] - The term "vehicle" refers to the solvent (liquid) that dissolves the solid solute to form a solution.

[0065] - The term "additive" refers to chemical substances (or molecules) that improve the physical properties (e.g. mechanical, optical, electronic, etc.) of a material.

[0066] - The terms "radio frequency identification tag" and "RFID" refer to remote identification, authentication and / or storage information technology, typically using five frequency bands: low frequency (LF) (125-134,2kHz), high frequency (HF) (13.56MHz), ultra-high frequency (UHF) (865-956MHz) and microwave frequencies (2.4GHz and 5.8GHz), corresponding to approximate read ranges of less than 0.5m, 1.2m, 5-10m and ultimately up to 10m, respectively. A "tag" is a simple resonant circuit consisting of inductive (L), capacitive (C) and resistive (R) elements on a plastic substrate ( Figure 1 ).

[0067] - The term "passive RFID" refers to a device that has no power source (such as a battery) and that uses energy from an RFID reader (reader) to operate.

[0068] -The term "RFID reader" or "reader" refers to a powered device consisting of a transceiver controlled by a microprocessor whose task is to request and receive response information from the tag. The reader communicates the data from the RFID antenna to the management system.

[0069] - The term "heterojunction" refers to an interface between semiconductor materials having different energy gaps and barriers for electrons and holes. In particular, the present invention relates to interfaces between organic semiconductors and inorganic semiconductors.

[0070] - The term "about" indicates a variation of + / - 10% of the indicated numerical value.

[0071] The semiconductor used as a temperature integrity sensor connected to a radio frequency identification tag (RFID), preferably a passive RFID, is based on a "photochromic twist switch" (PTS) architecture that allows π-conjugated organic compounds to adjust their optical and electronic properties by light stimulation, non-limiting examples of these compounds are Figure 2 shown.

[0072] First of all, it is worth pointing out that:

[0073] -Photochromic compounds cannot be used as organic semiconductors

[0074] -Organic semiconductors are not photochromic

[0075] -PTS derivatives are both semiconductors and photochromic compounds.

[0076] The compounds used in the present invention are known and described in US10144744, and can be represented by the following general structural formula (I), and the substituents thereof are also described in US10144744:

[0077]

[0078] Said compounds are known as components of electronic instruments, in particular optical, electronic or electro-optical devices, such as photochromic photovoltaic devices, organic multicolor light emitting diode devices or field effect light tunable organic transistors. However, they have never been used as temperature detectors, in particular they have never been used or described as temperature integrity (continuity) sensors in RFID radio frequency technology, especially in the field of passive RFID.

[0079] These compounds are designed to undergo conformational changes of their π conjugated systems by photoisomerization of a "molecular switch" orthogonally connected to a conjugated extension. The conformational changes of the π system make it possible to change the conductivity of the material. Therefore, in response to the absorption of light with a wavelength of about 360nm, these conductivity is higher (conjugated π planarization / conductive system) (cis conformation). On the contrary, when they absorb light with a lower wavelength (e.g., about 240-260nm, preferably 254nm), they become less conductive (distorted / poorly conductive conjugation) (trans conformation). In addition, over time, through their thermal relaxation, the compounds spontaneously change from a cis conformation with higher conductivity to a trans conformation with lower conductivity. This phenomenon is irreversible unless the trans conformation is irradiated again, and it is this natural phenomenon that is used to produce a temperature continuity sensor according to the present invention. Thermal relaxation can be prevented or slowed down at low temperatures, so the temperature continuity sensor according to the present invention is suitable for detecting whether the preset temperature remains constant or has changed until it reaches an undesirable level. Depending on the functional groups inserted into the azobenzene, the time required for thermal relaxation may vary from a few seconds (s) to several hours (h), and the expert in the field, based on the teachings of the following invention and his knowledge, will be able to determine the most suitable substituents and / or functional groups for the specific intended use of RFID.

[0080] PTS semiconductors are particularly advantageous when used in passive RFID devices as an alternative to complex circuits for low temperature (-5÷0°C) integrity (continuity) control in the cold chain. The conformational changes of the PTS semiconductor between its conductive and non-conductive forms are promoted at room temperature (20÷25°C) and inhibited at low temperatures (-5÷0°C). Therefore, the conductivity changes that follow the temperature changes of the PTS semiconductor will be interpreted as changes in the radio frequency of the RFID device. Therefore, the RFID device obtained in this way will be used to measure whether the temperature has continuity over time relative to a predetermined value, or whether an unexpected temperature increase has occurred. Therefore, the present invention relates to a device or a temperature sensor that allows detecting whether the object to which the sensor is applied has been maintained at the desired temperature, or whether the temperature has increased, resulting in an unexpected change in the temperature itself.

[0081] The temperature continuity sensor or device includes an RFID, which includes a support on which a thermoresponsive compound characterized by a π-conjugated system is applied, and the conformational change of the compound changes the conductivity of the compound, and the compound has a higher conductivity in response to the absorption of light wavelengths of about 360nm, and has a lower conductivity state in response to the absorption of shorter wavelengths of light. The thermoresponsive compound can be applied to the support in its lowest conductivity conformation (usually at room temperature) and then irradiated to make it more conductive, or it can be directly applied to the support in its highest conductivity conformation at a temperature below 0°C. In both embodiments, when the temperature is increased from 0°C to room temperature, it will spontaneously and irreversibly change from a more conductive conformation to a less conductive conformation.

[0082] The preferred compound of the present invention, also referred to as PTS, has the following general formula (II):

[0083]

[0084] in:

[0085] L is a hydrocarbon chain having 5 to 15 carbon atoms, in which up to 3 hydrocarbon moieties (-CH2-) can be replaced by one of the following moieties: O, NR L,1 , S, and / or wherein there may be up to 3 double or triple bonds, wherein pairs of the -CH2-CH2- type are replaced by -R L, 2C=CR L,3 -or- N=CR L,4 - Replacement, residue R L,1 -R l,4 independently selected from the group consisting of H, methyl, ethyl, propyl, isopropyl or benzyl;

[0086] W is selected from H, halogen, SR W,1 , methyl, ethyl, OR W,2 、COOR W,3 The group consisting of residues R W,1 -R W,3 are independently selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, phenyl or benzyl;

[0087] V1 and V2 are independently selected from the following groups: CH2, S, O, NH, COO, CO, CONR V,1 , residue R V,1 Selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, phenyl or benzyl;

[0088] A1 and A2 are independently selected from the following groups: S, O, NH, NR A,,1, BH, BR A,1 , PR A,1 , PR A,1 R A,2 , Se, CH=CH, CH=N, CH=PR A,1 R A,2 , CH2, C=O, C=CH2, C=CR A,1 R A,2 , residue R A,1 and R A,2 are independently selected from the group consisting of H, methyl, ethyl, propyl or benzyl;

[0089] X1 and X2 are independently selected from the following groups: N, CH;

[0090] Z1 and Z2 are independently selected from the following groups: halogen, methyl, ethyl, propyl, isopropyl, phenyl and benzyl, SR Z,1 , OR Z,2 、COOR Z,3 NR Z,4 R Z,5 、NO2、-CN、-SO3H,group R Z,1 -R Z,5 independently selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, benzyl and primary, secondary, and tertiary alkyl amines and primary, secondary, and tertiary phenyl amines;

[0091] P1 and P2 are a π-conjugated aromatic unit or a mixture of π-conjugated aromatic units, which can be independently selected from thiophene and its derivatives, ethylenedioxythiophene, indacenodithiophene, cyclopentadithiophene, phenyl and its derivatives, phenylvinylene, fluorene, indenofluorene, pyrene, pyrrole and its derivatives, pyrrole- 2-ketone, maleimide, 2,1,3-benzothiadiazole, dithienylpyrrole, oxadiazole, triazole, tetrazole, indole, carbazole or other groups selected from those shown in the following scheme (I), which groups may be substituted or unsubstituted, in which case R3 may preferably be hydrogen, halogen, methyl, ethyl, propyl, isopropyl, benzyl, phenyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, 3-methylheptane, 3-methoxyheptane, 7-methylpentadecane, 7-methoxypentadecane;

[0092]

[0093] Solution (I)

[0094] in

[0095] R1 and R2 are independently selected from the following groups: H, halogen, methyl, Sn(R R,1 )3, B(OH)2, OR R,2 NR R,3 R R,4 、NO2、COOR R,5 , COR R,6 , S R,7 、-CN、-CCR R,8 、-SO3H、-CR R,9 =C(CN)2, -CR R,10 =C(CN)(COOR R,11 ), -C(CN)=C(CN)2, methyldicyanovinyl, substituted N-ethylrhodanine and its derivatives, substituted and unsubstituted 3-(dicyanomethylidene)indan-1-one and its derivatives, substituted and unsubstituted ferrocene and its derivatives, substituted and unsubstituted pyridine and its derivatives including pyridine group, pentafluorophenyl, substituted and unsubstituted fullerene and its derivatives, alkyl primary amine, alkyl secondary amine, alkyl tertiary amine and phenyl primary amine, phenyl secondary amine and phenyl tertiary amine; the residue R R,1 -R R,11 independently selected from the group consisting of methyl, ethyl, propyl, isopropyl, phenyl, benzyl, and primary, secondary, and tertiary alkyl amines and primary, secondary, and tertiary phenyl amines;

[0096] And among them:

[0097] l is selected from an integer between 0 and 10, preferably 1, 2, 3, 4, 5, 6, 7, 8 or 9;

[0098] m is selected from an integer between 1 and 10, preferably 2, 3, 4, 5, 6, 7, 8 or 9;

[0099] n is selected from an integer between 0 and 10, preferably 1, 2, 3, 4, 5, 6, 7, 8 or 9;

[0100] x is selected from an integer between 1 and 10000, preferably an integer between 1 and 10, more preferably an integer between 2 and 10;

[0101] The condition is that l+n is at least 1.

[0102] Particularly preferred compounds of the present invention are compounds having a tetrathiophene group (Formula (III)) or a sexithiophene (Formula (IV)) or a fluorene-thiophene (Formula (V)) or a carbazole-thiophene (Formula (VI)) or a cyclopentadithiophene-thiophene (Formula (VII)) combined with azobenzene in the molecule, and the azobenzene acts as a molecular switch by light stimulation.

[0103]

[0104] in:

[0105] R1 and R2 are selected as described above;

[0106] R3 is selected as described above;

[0107] W is selected as described above;

[0108] The action range of compounds (III), (IV), (V), (VI) and (VII) is generally on the order of hours (h), with the maximum time for complete conversion from cis to trans being about 36 h.

[0109] Among compounds (III), (IV), (V), (VI) and (VII), the following compounds are particularly preferred, whose relaxation time is between 20 hours and 40 hours:

[0110]

[0111] The maximum transition time represents the length of time that the temperature integrity sensor can monitor a product. More specifically, using the above molecules, the temperature integrity sensor can monitor any product that may deteriorate within minutes, hours, or days (not exceeding the maximum transition time, e.g., 1.5 days) if exposed to incorrect storage temperatures.

[0112] The PTS architecture-based molecules to be integrated with the RFID antenna will be selected based on their cis-trans transition time to ensure that product deterioration does not exceed the cis-trans transition time.

[0113] The PTS compound can be applied to the label as a dilute solution by conventional methods known per se, selected from the group consisting of: brushing, dipping, spin coating, drop casting, doctor blade, blade coating, rod coating, spray coating, Langmuir-Blodgett deposition and slot die coating. A particularly preferred method according to the invention is drop casting. The solvent is then removed by evaporation with or without reduced pressure, possibly with the aid of heating on a hot plate at a temperature in the range of 30° C. to 100° C.

[0114] Useful solvents may be aprotic non-polar solvents (e.g. toluene, tetrahydrofuran, 2-methyl-tetrahydrofuran, 1,2,4-trimethylbenzene, o-xylene, anisole); or halogenated solvents (e.g. chlorobenzene, chloroform, dichloromethane, 1,2,4-trichlorobenzene; 1,2-dichlorobenzene), mixtures thereof and solvents having similar properties.

[0115] For example, but not limited to, the dilute solution can be prepared by weighing 1-10 parts (mg) of the PTS compound per 1 part (mL) of solvent and / or carrier.

[0116] The compound may be coloured and have a different colouration between the planar (cis-switching) and distorted (trans-switching) forms, and this colour change may be used, for example, in such a way that a temperature transition is apparent. Alternatively, any colour change may be concealed by covering the RFID antenna to prevent tampering intended to restore the product to its original temperature condition.

[0117] The RFID may be associated with an acoustic and / or optical signal to indicate that the product to which the antenna is applied has had a temperature discontinuity (increase) that has caused it to deteriorate.

[0118] According to other embodiments, the present invention is directed to an RFID tag device, which may be formed as follows.

[0119] Figure 7 A non-limiting schematic diagram is shown in FIG. 1 , which shows:

[0120] ○ A support, usually plastic or paper, that carries

[0121] o Metal antennas are usually made of aluminum or copper or conductive inks (based on silver or carbonaceous particles, for example).

[0122] o The PTS-based composition is deposited on the antenna or a portion thereof.

[0123] o All objects are protected by a light insulating layer (usually plastic or paper), specifically, the light insulating layer is insulating in the wavelength range of about 250nm to about 400nm.

[0124] The PTS semiconductor compound can be deposited as a thin film on the RFID tag antenna. The film is then activated by irradiation with a suitable wavelength, such as about 350 nm to about 360 nm, for a few seconds or minutes (based on the molecule used) to convert the PTS semiconductor from the initial non-conductive (or less conductive) trans form to the conductive cis form (tag activation).

[0125] Once the film of PTS material is activated, an insulating layer is applied, and the tag can be stored in a refrigerator or freezer, or applied directly to the product to be monitored.

[0126] Because some of the inherent physical properties of RFID circuits (such as frequency, impedance (Z) and reflection coefficient (S11)) are changed, an organic layer containing a PTS architecture deposited and activated on the antenna will result in a radio signal that is completely different from a non-functionalized antenna (without PTS material).

[0127] For example, if the device is stored at low temperatures (-5÷0°C), the radio signal obtained after activation of the PTS compound will remain unchanged. On the contrary, as the temperature gradually increases, the conductive cis-PTS molecules will gradually transform into the non-conductive (or less conductive) trans-form, thereby changing the frequency and / or impedance (Z) and / or reflection coefficient (S11) of the device in a way that is obvious and can be recorded by the reader.

[0128] When a reader interrogates the device, the response radio signal will depend on the state of progress of the conformation assumed by the material (cis-conducting and trans-non-conducting) (see Fig. 9 ).

[0129] Thus, the device according to the present invention provides an irreversible record of a specific temperature event to which the indicator (i.e., the PTS compound) applied to the device is exposed. The PTS temperature indicator will then be associated with a perishable host product to monitor the host product for exposure to temperatures above safe temperatures, thereby maintaining its integrity. Because the activated PTS compound is configured to undergo a conformational change in response to exposure to temperatures above the storage temperature (usually below 0°C), and therefore also a conductivity change. The change in conductivity, and therefore the device's response radio signal, may occur over a period of minutes to days, however pre-set for the specific product to be monitored.

[0130] An advantage of the device of the present invention is the use of PTS molecules, which are characterized by a spontaneous, unidirectional and irreversible change in molecular conformation, which in turn results in a change in conductivity, since the altered conductivity will persist after the PTS indicator material is no longer exposed to temperatures above the storage temperature. Thus, after the conductivity change, and after subsequent exposure to temperatures below the storage temperature, the PTS indicator material will retain the altered conductivity, thereby allowing the recording of temperature changes experienced by the product to be monitored.

[0131] According to other embodiments, the present invention is directed to an electronic system (e.g., a computer) and implemented by software for managing the control and detection of temperature continuity of a product that would spoil if subjected to a temperature above a temperature indicated as an optimal storage temperature for a period of time. The optimal temperature, temperatures above the optimal temperature, and the time above the optimal temperature vary from product to product and are determined by the manufacturer of the perishable product.

[0132] Perishable products are all edible products sold in the food distribution chain, including refrigerated and frozen products, pharmaceutical products stored below -5°C to +5°C (such as vaccines or antibiotics); or biomedical products (such as samples of body fluids or tissues, or organs).

[0133] The method is intended for managing the expiry date of products and is used, for example, by operators of points of sale of refrigerated / frozen products and all operators who need to obtain data on products stored at a temperature constantly below the degradation temperature (for example operators in the health department).

[0134] The method can be implemented by an electronic system (e.g. a computer) in combination with the RFID device of the invention, which method allows to ensure that the optimal storage temperature is maintained after the indicated expiration date, provided that the RFID device is separate, and the method is combined with a detection method, which allows to detect whether the product has been properly stored and whether the cold chain has been maintained without changes or tampering.

[0135] This method involves the Figure 8 The following process stages are rationalized in the flow chart shown.

[0136] The method for measuring the thermal integrity of a product includes the following steps:

[0137] i) Obtain sensor operation values, including:

[0138] - PTS-coated RFID synthesizes radio signals before and after activation with light,

[0139] - Transition time (thermal relaxation) from the "cis-conducting" to the "trans-non-conducting" conformation at different temperatures between -5÷0°C and 50°C (1÷5°C interval).

[0140] These values ​​will be measured and fed into the methods for managing the shelf life of the product;

[0141] ii) Obtain product control values ​​and thresholds, including:

[0142] -Optimal storage temperature value,

[0143] - the critical temperature threshold at which the product begins to deteriorate or enter the "danger zone",

[0144] - the maximum critical temperature time the product can be exposed to before it starts to deteriorate or enter the "danger zone",

[0145] These values ​​will be obtained by the supplier of the monitored product and inserted into the method for managing the expiration date of the product;

[0146] iii) Get sensor signal:

[0147] - The preservation state of the "cis-conductive" conformation of the PTS compound will be checked by an RFID reader, whose radio signal will be acquired and inserted into the method for managing the product's expiration date;

[0148] iv) The level of progress of thermal relaxation will be assessed by comparing:

[0149] - a radio signal read by the reader (iii),

[0150] - control values ​​and thresholds for product (ii),

[0151] - operating value of the sensor (i);

[0152] v) Measurement count and history, in order to generate a history of the number of measurements made and the relative times at which they were taken;

[0153] vi) Assign product health levels.

[0154] The save status of the product will be displayed in three alert levels:

[0155] - "good product", always in compliance with cryogenic storage (the final signal from the antenna is equal to the initial signal),

[0156] - “Product is in good condition”, following low temperature storage most of the time (the final signal from the antenna is different from the initial one, but also from the signal corresponding to reaching the threshold temperature);

[0157] - "Damaged product", not following low temperature storage (the final signal from the antenna is different from the initial signal, but is equal to or similar to the signal corresponding to reaching or exceeding the threshold temperature).

[0158] The method may be implemented by a computer program comprising code adapted to perform steps i) to vi) as defined above when executed on a system comprising an RFID, such as a computer, preferably a computer, a tablet, a smartphone or an equivalent system.

[0159] Another object of the invention is a computer support comprising the computer program as defined above.

[0160] The conversion process from conductive to non-conductive by means of thermal relaxation is unidirectional. Therefore, the conductive state can be maintained / stopped at low temperatures (T=-5°C-0°C) and its process can be restored at any time when the tag will be exposed to higher cold chain temperatures (T>5°C) (stop the process). Therefore, the integrity (continuity) of the low temperature in the cold chain will be recorded as a change in the radio frequency caused by the conversion process of the PTS semiconductor from conductive to non-conductive. In this way, if the product is stored outside the storage temperature, even temporarily, the history of the freeze-thaw-refrozen process will be recorded as a change in the radio signal.

[0161] The unidirectional aspect facilitates verification that the cold chain is maintained, precisely because the process is thermodynamically irreversible, i.e. the PTS unit does not return to its initial state solely by means of low temperatures. This makes it possible to extend the scope of the proposed technology to other fields (e.g. anti-counterfeiting). At the same time, the conversion of the PTS semiconductor from conductive to non-conductive is spontaneous, thus allowing working activities to be performed on the electronic circuit without the aid of an electrical power source (self-powered). Furthermore, the preparation process of the temperature integrity seal is compatible or easily integrated with current production marking processes, allowing to limit the production costs of the device and to expand the field of use of the proposed technology as a possible component of the "Internet of Things" (IoT).

[0162] The following examples are illustrative of the present invention and should not be construed as limiting the scope thereof.

[0163] method

[0164] Synthesis of PTS-based compounds.

[0165] The synthesis of the PTS1 unit is known and is described in US10144744 and Chem.Sci., 2017, 8, 361. Therefore, we report the synthesis procedure of the PTS2 unit and the functionalization procedure of the PTS1 unit and the PTS2 unit. The functionalized form of the PTS unit is the basis for the preparation of oligomers and polymers, so we also report here the general procedure for the synthesis of compounds containing the PTS unit as a monomer.

[0166] General procedure for the synthesis of PTS2 units, Figure 3 .

[0167] Compound 15: Under argon atmosphere, a mixture containing 3,3'-dibromo-2,2'-bithiophene (compound 13) (1.0 g, 3.09 mmol), hydroxybenzoic acid 14 (0.51 g, 3.70 mmol), Pd(PPh3)4 (0.71 g, 0.62 mmol) and K2CO3 (1.71 g, 12.34 mmol) was dissolved in a dioxane / water mixture (19 mL / 1 mL). The mixture was stirred and heated to 80 ° C for 48 hours and then allowed to reach room temperature. The reactants were then diluted by adding ethyl acetate, and the mixture was transferred to a separatory funnel and washed with brine. The organic phase was then dried over MgSO4 and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 1:1) to give 0.53 g (51%) of compound 15 as a white solid. 1 HNMR (400MHz, CDCl3): δ = 7.59 (d, J = 5.2Hz, 1H), 7.26 (t, J = 8.4Hz, 1H), 7.24 (d, J = 5.3Hz, 1H), 7.18 ( d, J=5.2Hz, 1H), 7.14 (dd, J=7.5, 1.2Hz, 1H), 6.98 (d, J=5.4Hz, 1H), 6.95-6.89 (m, 2H), 5.03 (s, 1H).

[0168] Compound 17: Under argon atmosphere, a mixture containing compound 15 (0.53 g, 1.56 mmol), compound 16 (1.09 g, 3.11 mmol), Pd (PPh 3) 4 (0.36 g, 0.31 mmol) and K 2 CO 3 (1.08 g, 7.79 mmol) was dissolved in DMF (5 mL). The mixture was stirred and heated to 95 ° C for 48 hours and then allowed to reach room temperature. The reactants were then diluted by adding ethyl acetate and the mixture was transferred to a separatory funnel and washed with brine. The organic phase was then dried over MgSO 4 and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: dichloromethane: ethyl acetate 9.5: 0.5) and then purified by a second column chromatography (eluent: petroleum ether: acetone 7: 3) to obtain 0.31 g (41%) of compound 17 in the form of a yellow solid. 1H NMR (400MHz, CDCl3): δ = 7.97 (d, J = 8.1Hz, 2H), 7.64 (s, 2H), 7.33 (t, J = 7.2Hz, 1H), 7.23 (d, J = 5.2Hz, 1H), 7.10 (dd, J = 7.5, 1 .4Hz,1H),7.02(d,J=8.3Hz,2H),6.99-6.94(m,3H),6.92(d,J=5.2Hz,1H),6.81(d,J=5.1Hz,1H),4.91(s,2H),2.08(s,6H).

[0169] Compound 18: A mixture containing 6-bromo-1-hexene (0.42mL, 3.15mmol), compound 17 (0.25g, 0.52mmol) and K2CO3 (0.22g, 1.57mmol) was dissolved in DMF (5mL). The mixture was stirred and heated to 95°C for 48 hours and then allowed to reach room temperature. The reactant was then diluted by adding ethyl acetate, and the mixture was transferred to a separatory funnel and washed with brine. The organic phase was then dried over MgSO4, and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 1:1) to obtain 0.21g (63%) of compound 18 as an orange solid. 1 H NMR (400MHz, CDCl3): δ = 7.95 (d, J = 8.9Hz, 2H), 7.56 (s, 2H), 7.31 (d, J = 8.8Hz, 1H), 7.24 (d, J = 5.2Hz, 1H),7.11(d,J=5.3Hz,2H),7.04(d,J=8.9Hz,2H),6.96-6.84(m,3H),6.78(d,J=5.2Hz,1H),5.95-5.8 1(m,1H),5.82-5.69(m,1H),5.15-4.82(m,4H),4.10(t,J=6.4Hz,2H),3.80(t,J=6.5Hz,2H),2.24-2 .07(m,2H),2.04(s,6H),2.02-1.95(m,2H),1.92-1.82(m,2H),1.74-1.46(m,4H),1.41-1.27(m,2H).

[0170] Compound 2 (PTS unit 2): A mixture containing compound 18 (100 mg, 0.15 mmol) and second generation Grubbs catalyst (25 mg, 0.03 mmol) was dissolved in anhydrous dichloromethane (800 mL) under argon atmosphere. The mixture was stirred and heated at 40 ° C for 6 hours and then allowed to reach room temperature. The mixture was then filtered through silica to remove the catalyst and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: dichloromethane: petroleum ether 7:3) to give 50.9 mg (53%) of compound 2 as an orange solid. 1 H NMR (400MHz, THF-d8): δ = 7.94 (d, J = 8.8Hz, 2H), 7.53 (d, J = 5.2Hz, 1H), 7.41 (s, 1H), 7.29 (d, J = 5.2Hz, 1H), 7.25 (s, 1H), 7 .18-7.08(m,3H),6.86(d,J=5.2Hz,1H),6.72(d,J=5.2Hz,1H),6.41(d,J=8.3Hz,1H),6.33(d,J=8.3Hz,1H),4.94(t,J=3. 2Hz,2H),4.37(t,J=5.0Hz,2H),3.48(s,3H),3.38-3.28(m,1H),3.23-3.04(m,1H),1.96(s,3H),1.94-1.89(m,2H),1.68- 1.57(m,2H),1.56-1.48(m,4H),1.45(s,3H),1.28-1.16(m,1H),1.16-1.08(m,1H),0.82-0.72(m,1H),0.69-0.57(m,1H).

[0171] General procedure for the synthesis of difunctionalized PTS unit precursors for Suzuki (Method A) and Stille (Method B) reactions, Figure 4 .

[0172] Compound 3: A 1M hexane solution of n-butyl lithium (0.41 mL, 0.641 mmol) was slowly added to a solution of diisopropylamine (0.099 mL, 0.705 mmol) in anhydrous THF (0.8 mL) at -78 ° C and an argon atmosphere. The reaction mixture was allowed to reach a temperature of 0 ° C and stirred for another 10 minutes. The resulting lithium diisopropylamide (LDA) solution was slowly added to a solution of PTS unit compound 1 (104 mg, 0.160 mmol) in anhydrous THF (1.3 mL) at -78 ° C. The resulting mixture was stirred for about 3 hours at -78 ° C. Next, an anhydrous THF (0.4 mL) solution of iodine was added to the reaction mixture at -78 ° C. The resulting reaction mixture was stirred for about 24 hours, allowing the temperature to slowly rise to room temperature. The reaction was quenched by adding a saturated NH4Cl solution, and the mixture was transferred to a separatory funnel and washed with ethyl acetate and brine. The organic phase was then dried over MgSO4, and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 1:1) to give 87 mg (60%) of the desired product (compound 3) as a brown oil. 1 H NMR (400MHz, THF-d8): δ = 7.90 (d, J = 8.8Hz, 2H), 7.40 (s, 1H), 7.20 (s, 1H), 7.13 (t, J = 8.3Hz, 1H), 7.07 (d, J = 8. 9Hz,2H),7.03(s,1H),6.83(s,1H),6.39(d,J=8.3Hz,1H),6.29(d,J=8.3Hz,1H),4.93-4.88(m,2H),4.36-4.3 0(m,2H),3.50(s,3H),3.33-3.26(m,1H),3.15-3.07(m,1H),1.97(s,3H),1.93-1.88(m,2H),1.63-1.55(m,2H ),1.54-1.46(m,4H),1.38(s,3H),1.24-1.18(m,1H),1.12-1.04(m,1H),0.76-0.70(m,1H),0.65-0.58(m,1H).

[0173] Compound 4: At -78 ° C and under an argon atmosphere, a 1M hexane solution of n-butyl lithium (0.337 mL, 0.844 mmol) was slowly added to a solution of diisopropylamine (0.130 mL, 0.928 mmol) in anhydrous THF (1 mL). The reaction mixture was allowed to reach a temperature of 0 ° C and stirred for another 10 minutes. At -78 ° C, the resulting lithium diisopropylamide (LDA) solution was slowly added to a solution of PTS unit compound 2 (130 mg, 0.211 mmol) in anhydrous THF (1.8 mL). The resulting mixture was stirred for about 3 hours at -78 ° C. Next, an anhydrous THF solution (0. mL) of iodine (321 mg, 1.266 mmol) was added to the reaction mixture at -78 ° C. The resulting reaction mixture was stirred for about 24 hours, and the temperature was slowly raised to room temperature. The reaction was quenched by adding a saturated NH4Cl solution, and the mixture was transferred to a separatory funnel and washed with ethyl acetate and brine. The organic phase was then dried over MgSO4 and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 7:3) to give 108 mg (59%) of the desired product (compound 4) as a brown oil. 1 H NMR (400MHz, THF-d8): δ = 7.90 (d, J = 8.8Hz, 2H), 7.40 (s, 1H), 7.16 (s, 1H), 7.15 (d, J = 10.4Hz, 1H), 7.12 (s, 1H) ),7.07(d,J=8.8Hz,2H),7.02(s,1H),6.81(d,J=7.3Hz,1H),6.70(t,J=7.4Hz,1H),6.64(d,J=8.3Hz,1H),4.9 6-4.91(m,2H),4.36-4.30(m,2H),3.42-3.33(m,1H),3.19-3.11(m,1H),1.92(s,3H),1.66-1.58(m,2H),1.56 -1.46(m,4H),1.95-1.89(m,5H),1.32-1.22(m,1H),1.20-1.09(m,1H),0.81-0.72(m,1H),0.70-0.60(m,1H).

[0174] Compound 5: A 1M hexane solution of n-butyl lithium (0.17 mL, 0.421 mmol) was slowly added to a solution of diisopropylamine (0.065 mL, 0.463 mmol) in anhydrous THF (0.5 mL) at -78 ° C and an argon atmosphere. The reaction mixture was allowed to reach a temperature of 0 ° C and stirred for another 10 minutes. The resulting lithium diisopropylamide (LDA) solution was slowly added to a solution of PTS unit compound 1 (68 mg, 0.105 mmol) in anhydrous THF (0.9 mL) at -78 ° C. The resulting mixture was stirred for about 3 hours at -78 ° C. Next, a solution of trimethyl chloro stannane (126 mg, 0.631 mmol) in anhydrous THF (0.3 mL) was added to the reaction mixture at -78 ° C. The reaction mixture was stirred for about 24 hours, allowing the temperature to slowly rise to room temperature. Ethyl acetate was then added to dilute the reactants, and the mixture was transferred to a separatory funnel and washed with brine. The organic phase was then dried over MgSO4 and the organic solvent was evaporated under reduced pressure. The desired product (Compound 5) (93.8 mg, 98%) was obtained as a yellow solid without further purification. 1 H NMR (400MHz, THF-d8): δ = 7.89 (d, J = 8.8Hz, 2H), 7.34 (s, 1H), 7.18 (s, 1H), 7.08 (t, J = 8.3Hz, 1H), 7.06 (d, J = 8.9Hz, 2H), 6.88 ( s,1H),6.76(s,1H),6.33(d,J=8.3,1H),6.25(d,J=8.3,1H),4.90(t,J=3.1Hz,2H),4.34-4.30(m,2H),3.38(s,3H),3.32-3.2 5(m,1H),3.12-3.04(m,1H),1.94-1.89(m,2H),1.87(s,3H),1.63-1.55(m,2H),1.53-1.46(m,4H),1.43(s,3H),1.21-1.14(m ,1H),1.13-1.05(m,1H),0.78-0.70(m,1H),0.67-0.61(m,1H),0.46(s,1H),0.39(s,7H),0.30(s,8H),0.23(t,J=5.0Hz,2H).

[0175] General procedure for the synthesis of PTS compounds by Suzuki (Method A) and Stille (Method B), Figure 5 .

[0176] As a non-limiting example of Method A and Method B, the following procedure is applicable to the synthesis of compounds 6, 7 and 8.

[0177] Method A, PTS tetrathiophene with OMe (Compound 6): Under argon atmosphere, a mixture containing PTS unit diiodate (Compound 3) (30 mg, 0.033 mmol), thiophene-2-boronic acid 9 (21 mg, 0.0.167 mmol), Pd(PPh3)4 (7.6 mg, 0.007 mmol) and K2CO3 (23 mg, 0.166 mmol) was dissolved in DMF (1 mL). The mixture was stirred and heated to 85 ° C for 18 hours and then allowed to reach room temperature. The reactants were then diluted by adding ethyl acetate and the mixture was transferred to a separatory funnel and washed with brine. The organic phase was then dried over MgSO4 and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 1:1) to give 16.8 mg (62%) of compound 6 as an orange solid.

[0178] Method B, PTS tetrathiophene with OMe (Compound 6): Under argon atmosphere, a mixture containing mono-PTS di-stannate (Compound 5) (79 mg, 0.088 mmol), 2-bromothiophene 10 (42 μL, 0.437 mmol), Pd(PPh3)4 (20 mg, 0.018 mmol) was dissolved in DMF (2.6 mL). The mixture was stirred and heated to 85 ° C for 15 hours and then allowed to reach room temperature. The reactants were then diluted by adding ethyl acetate and the mixture was transferred to a separatory funnel and washed with brine. The organic phase was then dried over MgSO4 and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 1:1) to give 29 mg (41%) of compound 6 as an orange solid. 1H NMR (400MHz, THF-d8): δ = 7.91 (d, J = 8.8Hz, 2H), 7.42 (s, 1H), 7.34 (d, J = 5.1Hz, 1H), 7.30 (d, J = 3.6Hz, 1H), 7.26 (d, J = 4.9Hz, 1H), 7.23 (s, 1H), 7 .16(d,J=2.4Hz,1H),7.14(t,J=8.3Hz,1H),7.07(d,J=9.0Hz,2H),7.04(dd,J=5.5,4.3Hz,1H),7.02(s,1H),6.98(dd,J=5.0,3.6Hz,1H),6.85(s ,1H),6.41(d,J=8.3Hz,1H),6.31(d,J=8.3Hz,1H),4.93-4.88(m,2H),4 .38-4.29(m,2H),3.53(s,3H),3.38-3.29(m,1H),3.19-3.09(m,1H),2. 05(s,3H),1.94-1.87(s,2H),1.63-1.55(m,2H),1.52-1.44(m,7H),1.3 0-1.20(m,1H),1.17-1.08(m,1H),0.80-0.70(m,1H),0.69-0.57(m,1H).

[0179] Method A, PTS sexithiophene with OMe (Compound 7): Under argon atmosphere, a mixture containing PTS unit diiodate (Compound 3) (49.2 mg, 0.055 mmol), 2-([2,2'-dithiophene]-5-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 12 (79.9 mg, 0.273 mmol), Pd(PPh3)4 (12.6 mg, 0.011 mmol) and K2CO3 (37.7 mg, 0.7 mmol) was dissolved in DMF (1 mL). The mixture was then heated to 85°C and stirred for 2 hours. The reaction mixture was then allowed to reach room temperature and transferred to a separatory funnel and washed with DCM and brine. The organic phase was then dried over MgSO4 and the solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 1:1) to give 35.3 mg (66%) of compound 7 as an orange solid. 1H NMR (400MHz, THF): δ = 7.91 (d, J = 8.8Hz, 2H), 7.43 (s, 1H), 7.34 (d, J = 5.0Hz, 1H), 7.91 (d, J = 8.8Hz, 1H), 7.25 (d, J = 3.6Hz, 2H), 7.24 (s, 1H), 7.19 (t, J =3.3Hz,2H),7.16(t,J=8.3Hz,1H),7.11(q,J=3.9Hz,2H),7.07(d,J=8.9H z,2H),7.06(s,1H),7.03(dd,J=5.0,3.7Hz,1H),6.99(dd,J=5.0,3.7Hz,1H ),6.88(s,1H),6.42(d,J=8.3Hz,1H),6.32(d,J=8.4Hz,1H),4.94-4.88(m ,2H),4.37-4.28(m,2H),3.54(s,3H),3.38-3.30(m,1H),3.21-3.09(m,1H ),2.06(s,3H),1.95-1.86(m,2H),1.65-1.55(m,2H),1.55-1.44(m,7H),1 .33-1.21(m,1H),1.20-1.07(m,1H),0.81-0.71(m,1H),0.69-0.59(m,1H).

[0180] Method B, PTS tetrathiophene with H instead of OMe, compound 8: Under argon atmosphere, a mixture containing PTS unit diiodide (compound 4) (20 mg, 0.088 mmol), trimethyltin 2-thiophene 11 (28 mg, 0.12 mmol), Pd (PPh3) 4 (5.3 mg, 0.05 mmol) was dissolved in DMF (1 mL). The mixture was stirred and heated to 85 ° C for 15 hours and then allowed to reach room temperature. The reactants were then diluted by adding ethyl acetate and the mixture was transferred to a separatory funnel and washed with brine. The organic phase was then dried over MgSO4 and the organic solvent was evaporated under reduced pressure. The final product was finally purified by silica gel chromatography (eluent: petroleum ether: dichloromethane 1:1) to give 17.4 mg (97%) of compound 8 as an orange solid. 1H NMR (400MHz, CDCl3): δ=7.94(d,J=8.9Hz,2H),7.43(s,1H),7.27(t,J=5.2Hz,1H),7.23-7.17(m,4H),7.09(d,J=3.7H z,1H),7.08(s,1H),7.07(s,1H),7.05(d,J=4.3Hz,1H),7.04(s,1H),7.02(dd,J=5.2,1.6Hz,1H),7.01(s,1H),6.99( dd,J=7.5,1.7Hz,1H),6.76(t,J=7.4Hz,1H),6.62(d,J=8.2Hz,1H),5.02-4.89(m,2H),4.35(t,J=5.4,2H),3.45-3.3 6(m,1H),3.21-3.11(m,1H),2.04(s,3H),1.99-1.91(m,2H),1.57-1.52(m,2H),1.46(s,7H),1.39-1.29(m,1H),1.26 48-1.13(m,1H),0.89-0.74(m,1H),0.72-0.58(m,1H).

[0181] UV-Vis was used to measure the transition from conductive to non-conductive (thermal relaxation), Figure 6 .

[0182] In the first step, the conversion time of the PTS molecule from the conductive form to the non-conductive form is tested by UV-vis spectroscopy. The PTS molecule is dissolved in an organic solvent (e.g., tetrahydrofuran (THF)) to a concentration such that the signal intensity of the absorption spectrum measured by a UV-vis spectrophotometer does not exceed a value of 0.1 in relative units (au). The cuvette containing the above solution is irradiated with a wavelength of about 360 nm for 10-30 seconds, or until no further changes in the absorption spectrum are detected, indicating that the PTS molecule is completely converted from the non-conductive form to the conductive form. Once complete conversion to a conductive state is confirmed, the RFID is placed in an incubator at a temperature of 25°C, and its progress from conductive to non-conductive (thermal relaxation) is measured regularly (e.g., once every 6 hours), such as Figure 6 shown.

[0183] General procedure for converting a commercial RFID into an integrity sensor.

[0184] On a passive RFID, for example operating at 13.56 MHz (NFC tag), a dry aluminum circuit is embedded (dry embedded chip) on a PET (polyethylene terephthalate) support, there is no glue on the support, no protective layer on the circuit, and the NXP identification chip Ntag203 is deposited using a drop casting method using a tetrahydrofuran (THF) solution containing about 5 mg / mL of PTS compound. The RFID is then heat treated (cured) for 5-10 minutes by placing the latter on a hot plate at 40°C to promote the evaporation of the solvent and obtain a thin film of PTS material. The RFID, which is fully or partially coated with the PTS material, is then irradiated with a wavelength of about 360 nm for 5-10 minutes, or until no further radio signal changes are detected, indicating a complete conversion of the PTS molecules from non-conductive to conductive (activation of the material).

[0185] Determine the transition from conductive to non-conductive (thermal relaxation) by switching at different temperatures, reflection confidence (S11) and frequency, Fig. 9 .

[0186] Initially at room temperature, the RFID antenna signal was detected by a network analyzer (3GHz Nanovna V2 Vector Network Analyzer SAA2) before and after deposition of the PTS material and after activation of the material. The measured changes in the radio signal (e.g., reflection confidence (S11), frequency, and impedance (Z)) when the PTS material is in its non-conductive and conductive states establish the RFID radio signal.

[0187] Once the RFID signal is detected at room temperature, the activated tag is stored in a refrigerator at 0°C and its storage state is measured every 24 hours for 4 days. Once the retention of the activation state is verified, the RFID is exposed to an incubator at 25°C and its progression from conductive to non-conductive (thermal relaxation) is measured regularly (e.g., once every 24 hours). Fig. 9 .like Fig. 9 As shown, the transition from conductive to non-conductive is a function of the time and temperature of RFID exposure. In this way, the intermediate signal associated with the partial transition from cis (planar π-conjugated / conductive conformation of the PTS compound) to trans (distorted π-conjugated / non-conductive conformation) can be measured, as well as the final signal once the complete conversion to trans (distorted / non-conductive π-conjugated conformation) is complete. In addition, the minimum time required for the initial (pre-activated with light) trans conformation (distorted π-conjugated / non-conductive conformation) to fully recover can be measured.

[0188] The present invention has been described with reference to preferred embodiments. It should be understood that various modifications can be made without departing from the spirit and scope of the present invention. Therefore, other embodiments are within the scope of the following claims.

Claims

1. A temperature sensor comprising an RFID, wherein the RFID comprises: A support having applied thereto a thermoresponsive compound characterized by a π-conjugated system, wherein a conformational change of the thermoresponsive compound changes the conductivity of the compound, wherein the compound has a higher conductivity in response to the absorption of light having a wavelength of about 360 nm relative to a lower conductivity state in response to the absorption of light having a lower wavelength, The thermoresponsive compound is applied in its most conductive conformation at a temperature below 0°C, and spontaneously, irreversibly and unidirectionally changes from the most conductive conformation to the least conductive conformation when the temperature rises from 0°C to room temperature.

2. The sensor according to the preceding claim, wherein the compound has the general formula (II): in: L is a hydrocarbon chain having 5 to 15 carbon atoms, in which up to 3 hydrocarbon moieties (-CH2-) can be replaced by one of the following moieties: O, NR L,1 , S, and / or wherein there may be up to 3 double or triple bonds, wherein pairs of the -CH2-CH2- type are replaced by -R L,2 C=CR L,3 -or- N=CR L,4 - Substitution, residue R L,1 -R l,4 independently selected from the group consisting of H, methyl, ethyl, propyl, isopropyl or benzyl; W is selected from H, halogen, SR W,1 , methyl, ethyl, OR W,2 、COOR W,3 The group consisting of residues R W,1 -R W,3 are independently selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, phenyl or benzyl; V1 and V2 are independently selected from the following groups: CH2, S, O, NH, COO, CO, CONR V,1 , residue R V,1 Selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, phenyl or benzyl; A1 and A2 are independently selected from the following groups: S, O, NH, NR A,,1 , BH, BR A,1 , PR A,1 , PR A,1 R A,2 , Se, CH=CH, CH=N, CH=PR A,1 R A,2 , CH2, C=O, C=CH2, C=CR A,1 R A,2 , residue R A,1 and R A,2 are independently selected from the group consisting of H, methyl, ethyl, propyl or benzyl; X1 and X2 are independently selected from the following groups: N, CH; Z1 and Z2 are independently selected from the following groups: halogen, methyl, ethyl, propyl, isopropyl, phenyl and benzyl, SR Z,1 , OR Z,2 、COOR Z,3 NR Z,4 R Z,5 、NO2、-CN、-SO3H,group R Z,1 -R Z,5 independently selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, benzyl and primary, secondary, and tertiary alkyl amines and primary, secondary, and tertiary phenyl amines; P1 and P2 are a π-conjugated aromatic unit or a mixture of π-conjugated aromatic units, which can be independently selected from thiophene and its derivatives, ethylenedioxythiophene, indenodithiophene, cyclopentadithiophene, phenyl and its derivatives, phenylvinylene, fluorene, indenofluorene, pyrene, pyrrole and its derivatives, pyrrol-2-one, maleimide, 2,1,3-benzothiadiazole, dithienylpyrrole, oxadiazole, triazole, tetrazole, indole, carbazole or other groups selected from those shown in the following scheme (I), which groups can be substituted or unsubstituted, and in the case of substitution, R3 can preferably be hydrogen, halogen, methyl, ethyl, propyl, isopropyl, benzyl, phenyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, 3-methylheptane, 3-methoxyheptane, 7-methylpentadecane, 7-methoxypentadecane; Solution (I) Wherein R1 and R2 are independently selected from the following groups: H, halogen, methyl, Sn(R R,1 )3, B(OH)2, OR R,2 NR R,3 R R,4 、NO2、COOR R,5 , COR R,6 , S R,7 、-CN、-CCR R,8 、-SO3H、-CR R,9 =C(CN)2, -CR R,10 =C(CN)(COOR R,11 ), -C(CN)=C(CN)2, methyl dicyanovinyl, substituted N-ethylrhodanine and its derivatives, substituted and unsubstituted 3-(dicyanomethylene)indan-1-one and its derivatives, substituted and unsubstituted ferrocene and its derivatives, substituted and unsubstituted pyridine and its derivatives including pyridine group, pentafluorophenyl, substituted and unsubstituted fullerene and its derivatives, alkyl primary amine, alkyl secondary amine, alkyl tertiary amine and phenyl primary amine, phenyl secondary amine and phenyl tertiary amine; the residue R R,1 -R R,11 independently selected from the group consisting of methyl, ethyl, propyl, isopropyl, phenyl, benzyl, and primary, secondary, and tertiary alkyl amines and primary, secondary, and tertiary phenyl amines; And among them: l is selected from an integer between 0 and 10; m is selected from an integer between 1 and 10; n is selected from an integer between 0 and 10; x is selected from an integer between 1 and 10000, preferably an integer between 1 and 10; The condition is that l+n is at least 1.

3. The temperature sensor according to any one of the preceding claims, wherein the compound is selected from the compounds of formula (III), (IV), (V), (VI), (VII):

4. A temperature sensor according to any one of the preceding claims, wherein: The RFID also includes: -antenna - Optional microchip - an active material layer comprising one or more thermally responsive compounds -Insulation layer.

5. The temperature sensor according to the preceding claim, wherein the one or more thermally responsive compounds are applied on the antenna.

6. The temperature sensor according to any one of claims 4 to 5, wherein: The active material layer is deposited on the entire antenna, or on a portion of the antenna, or on a portion of a support interposed between the microchip and the antenna, so as to connect the microchip to the antenna.

7. The temperature sensor according to any one of claims 1 to 6, wherein: The RFID is of a passive type or an active type.

8. A component, which is a temperature detector and comprises a sensor according to any one of claims 1 to 7 and an RFID reader, and which is preferably a smartphone.

9. An article comprising a sensor according to any one of the preceding claims or associated with a component according to any one of the preceding claims.

10. The article according to the preceding claim, which is or contains a product which is sensitive to temperature changes.

11. A composition comprising one or more compounds according to any one of claims 1 to 3 and a component selected from a carrier and an additive and a mixture thereof.

12. A heterojunction formed by the composition according to the preceding claim and the RFID according to any one of claims 1 to 8.

13. Compounds of Formula 6, Formula 7, Formula 8, Formula 19, Formula 20, Formula 21, Formula 22, Formula 23, Formula 24, Formula 25, Formula 26, Formula 27, Formula 28, Formula 29, and Formula 30:

14. Use of a compound according to any one of claims 1 to 3 and 12 or a composition according to claim 11 for checking temperature continuity in an RFID device, or in a part of such a device, or in an assembly comprising such a device.

15. A method for measuring the temperature continuity of a product, comprising the steps of: The sensor according to claims 1 to 5 is irradiated by applying radiation having a wavelength of about 330-380 nm, preferably about 360 nm.

16. A computer-implemented method for measuring temperature continuity of a product, comprising the steps of: i) obtaining an operating value of a temperature continuity detector device; ii) Obtaining control values ​​and thresholds of the inspected products; iii) obtaining a signal from a temperature continuity detector device; iv) assessing the level of progression of thermal relaxation; v) measurement count and history; vi) Health level of the allocated product.

17. A computer program comprising code capable of performing steps i) to vi) as defined in the preceding claims when executed on a computer.

18. A computer program according to the preceding claim, executed via a smartphone application or other RFID reader.

19. Computer medium comprising a program according to any one of claims 17-18.

20. A device or a computer or a computing medium implementing the method of claim 16.

21. The device or computer or computing medium according to the preceding claim, selected from: an RFID reader or a mobile device, such as a scanner, a mobile phone, a PDA, a smartphone, a tablet computer, a laptop.

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