JP2010217022A - Calixresorcinarene compound, and sensor element and sensor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel calixresorcinarene compound capable of selectively adsorbing VOCs (volatile organic compounds) having a specific substituent such as, ketone molecule, and to provide a sensor element and a sensor which use the calixresorcinarene compound suitable for detecting ketone molecules. <P>SOLUTION: The calixresorcinarene compound is obtained by introducing a side chain which adsorbs the ketone molecule, in calixresorcinarene used as a basic skeleton, and by compounding it with polydimethylsiloxane. The sensor element 1 is configured by forming a sensitive membrane 3 on a substrate 2, and the sensitive membrane 3 is made of the calixresorcinarene compound. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel calixresorcinarene-based composite material, a sensor element using the same, and a sensor.

In the field of chemical sensors, MOS (Metal Oxide Semiconductor) type sensors using oxide semiconductors are generally used.
The MOS type sensor is based on a relatively small fine particle crystal or sintered body of a metal oxide made into a semiconductor, and usually comprises a ceramic structure having an electrode wire such as Pt inside. The MOS type sensor is used at a high temperature of about 300 ° C. Due to the catalytic reaction at a high temperature on the metal oxide surface, gas molecules such as alcohol are reduced on the surface, and electrons are taken into the depleted metal oxide and neutralized. This utilizes the principle that the potential barrier at the grain boundary is lowered and the resistance is lowered. This MOS sensor is used as a sensor for alcohol and propane gas, but it has insufficient sensitivity, lacks selectivity for gas, is difficult to integrate, and requires high-temperature sensing There are problems such as.

  In recent years, research to increase the sensitivity of chemical sensors that detect chemical substances such as various volatile organic compounds (hereinafter referred to as VOCs) such as benzene, toluene, alkanes, and alcohols, and chemistry tailored to the chemical substances to be detected Research on sensors has been conducted, and various proposals have been made on sensitive materials for chemical sensors.

  For example, Patent Document 1 describes a sensor in which a sensitive film is formed of a rubber-based material having a double bond on the surface of a piezoelectric vibrator. Patent Document 2 describes an ion concentration measurement ion sensor that forms a porphyrin-sensitive film and measures hydrogen ion, hydrofluoric acid, metal ion concentration, and the like. Patent Document 3 describes that a chemical gas sensor material containing a thin-film crown ether condensed phthalocyanine-based compound is formed on a crystal resonator and detects gases such as NOx and SOx.

  However, at present, no sensitive material has been found that uses a VOCs having a specific substituent such as a ketone molecule as a detection target of a chemical sensor. It is known that the type and concentration of VOCs contained in exhaled breath changes when suffering from a disease, and that ketone derivatives are released from cancer patients. Select VOCs having specific substituents such as ketone molecules selectively. There is a need for sensitive materials that adsorb.

JP-A-11-108818 JP 2004-37430 A JP 7-43285 A

  The present invention has been made based on such a technical problem, and an object thereof is to provide a novel calixresorcinarene-based composite material capable of selectively adsorbing VOCs having a specific substituent such as a ketone molecule. And It is another object of the present invention to provide a sensor element and a sensor using a calix resorcin allen-based composite material.

  For this purpose, the present inventors have introduced a side chain that adsorbs a ketone molecule with calixresorcinarene as a basic skeleton, and further controls the molecular arrangement of calixresorcinarene by complexing with polydimethylsiloxane. Thus, it was found that ketone molecules can be selectively adsorbed.

  That is, the present invention is a calix resorcinarene-based composite material represented by [Chemical Formula 1].

In [Chemical _Formula 1], R represents a linear alkyl group selected from _C2-12 . n represents an integer selected from 1 to 500.

  The present invention also provides a sensor element in which a sensitive film is formed on a substrate, wherein the sensitive film is made of a calix resorcin allen-based composite material represented by the following [Chemical Formula 2]. is there.

In [Chemical _Formula 2], R represents a linear alkyl group selected from _C2-12 . n represents an integer selected from 1 to 500.
In the sensor element of the present invention, the substrate is preferably made of gold, or made of a silicon-based material with a gold thin film formed on the surface.

  Furthermore, the present invention relates to a sensor element in which a sensitive film made of a calix resorcinarene-based composite material represented by [Chemical Formula 3] is formed on a substrate, a target substance adsorbed by the sensitive film, and a sensor based on the adsorbed target substance And a detecting means for detecting a physical change of the element.

In [Chemical _Formula 3], R represents a linear alkyl group selected from _C2-12 . n represents an integer selected from 1 to 500.
In the sensor of the present invention, the detection means is preferably detection means for detecting a mass change due to the adsorbed target material as a frequency change of the vibration type mass detection sensor.

  The calixresorcinarene-based composite material of the present invention is a sensitive material having selectivity for VOCs having a specific substituent such as a ketone molecule. The sensor element and sensor using the calixresorcinarene-based composite material of the present invention can detect VOCs having a specific substituent such as a ketone molecule.

(A) The perspective view of the board | substrate which comprises a sensor element, (b) The perspective view of the sensor element which formed the sensitive film | membrane on the board | substrate. It is a schematic diagram of a QCM sensor. (A)-(d) is a figure for demonstrating the synthesis | combining method of the calix resorcinarene type composite material of [Chemical formula 4]. It is a figure showing the frequency change at the time of introduce | transducing acetone in increments of 100 ppm in the range of 500 ppm-2000 ppm. It is a figure showing the frequency change at the time of introducing octane by increasing by 100 ppm in the range of 500 ppm to 2000 ppm. It is a figure showing the frequency change at the time of introduce | transducing 1000 ppm each of acetone, ethanol, toluene, and octane.

Hereinafter, the present invention will be described in more detail.
<Calyx resorcin allen-based composite material>
The calixresorcinarene-based composite material of the present invention is represented by [Chemical Formula 1] [Chemical Formula 2] [Chemical Formula 3], and has selectivity for ketone molecules. About this reason, the present inventors guess as follows. Since calixresorcinarene has a capsule-type molecular structure, it can be used as a molecular recognition material. By introducing an amide group into this calix resorcinarene, selectivity for ketone molecules is imparted. However, when a sensitive film is formed only by calix resorcin allene molecules, the adsorption of ketone molecules is inhibited by intramolecular or intermolecular bonding. In order to prevent this, a network structure is formed by compounding with polydimethylsiloxane, and it is considered that the target substance easily enters the calixresorcinarene-based composite material.

Since the calixresorcinarene-based composite material of the present invention can selectively adsorb a target substance, it can be used as a molecular recognition film of a chemical sensor.
In the present invention, the target substance means a gas component to be detected, and at least ketone molecules can be detected, but other VOCs may be detected. The adsorption of the target substance means physical and chemical adsorption of the target substance to the calix resorcinarene-based composite material. A ketone molecule is an organic compound having a ketone group.

R and n of the calix resorcinarene-based composite material of the present invention will be described.
R is a linear alkyl group selected from _C2-12 ( _C2-12 ). By changing the length of the linear alkyl group, it is possible to control molecular solubility and selectivity for VOCs gas such as hydrocarbons.
n is the degree of polymerization of polydimethylsiloxane. Since the mobility (hardness) of the polymer is changed by changing the degree of polymerization to control the diffusion of the VOCs gas, the degree of polymerization can be adjusted to the desired mobility, but the degree of polymerization n is 1 to 1 Preferably, 500 is selected.
As an example of a calixresorcinarene-based composite material synthesized by the present inventors, a method for synthesizing a calixresorcinarene-based composite material in which R is C ₁₁ will be described in the following examples.

<Sensor element>
The sensor element of the present invention is a sensor element in which a sensitive film is formed on a substrate, and the sensitive film is composed of a calix resorcin allen-based composite material containing a repeating unit represented by [Chemical Formula 2]. This is a characteristic sensor element.
The substrate is preferably a substrate made of gold or having a gold (Au) thin film formed on the surface of a Si-based material. A substrate in which a gold thin film is formed on the surface of a Si-based material can be used as an electrode of a vibration type mass detection sensor such as a crystal resonator.

  The configuration of the sensor element will be described with reference to FIGS. FIG. 1A shows a perspective view of the substrate 2 constituting the sensor element. FIG. 1B shows a perspective view of the sensor element 1 on which the sensitive film 3 is formed.

As shown in FIG. 1A, the substrate 2 has a gold electrode 4 formed at the center of the substrate 2, and can be energized from the outside by a gold electrode terminal portion 4 a connected to the gold electrode 4. As the substrate 2, a crystal resonator (manufactured by Tama Device Co., Ltd.) having a crystal element plate size φ8.7 mm and a gold electrode 14 having a diameter φ5.0 mm can be used.
As shown in FIG. 1B, the sensor element 1 has a configuration in which a sensitive film 3 is formed on the gold electrode 4 shown in FIG.

  The sensitive film of the sensor element of the present invention can be produced by the following method. A calixresorcinarene derivative and polydimethylsiloxane are dissolved in xylene to prepare a mixed solution. After adding a Pt catalyst and stirring, the mixed solution is spin-coated on the substrate, and the xylene is dried. A sensitive film made of a calixresorcinarene-based composite material in which a derivative and polydimethylsiloxane are bonded is obtained.

<Sensor>
The calixresorcinarene-based composite material of the present invention and the sensor element using the same are suitable for sensors having detection means such as electrical detection, optical detection, chemical detection, and electrochemical detection.

  When the sensor element of the present invention is applied to a sensor, it is preferable to detect a mass change due to adsorption / desorption of the target substance as a frequency change using a vibration type mass detection sensor. By arranging the calix resorcin allen-based composite material of the present invention using the electrode on the vibration mass detection sensor as a substrate, a highly sensitive sensor is obtained. As the vibration type mass detection sensor, a sensor using a crystal resonator is preferable. Further, a vibration type mass detection sensor using a small vibrator using a MEMS (Micro Mechanical Electrical System) technique can be used. In this case, integration and integration with a circuit are easier than QCM.

For example, in a quartz crystal microbalance (QCM), when a substance is adsorbed on the surface of the crystal oscillator, the fundamental frequency of the crystal oscillator is proportional to the mass of the adsorbed substance according to the Sauerbrey equation (1) below. Change. Here, Δf is frequency change (Hz), F ₀ is resonance frequency (9 MHz), Δm is weight change, A is electrode area, ρ _q is crystal density, and μ _q is rigidity of AT-cut crystal. . In the examples described later, the measurement was performed under the conditions of A of 0.1963 cm ² , ρ _q of 2.648 g / cm ³ , and μ _q of 2.947 × 10 ¹¹ gHz ² / cm.

FIG. 2 is a diagram for explaining the configuration of the sensor.
As shown in FIG. 2, in the sensor 20, an oscillator 23 that generates vibration and a sensor element 1 placed on the oscillator 23 via a terminal 24 are installed in a chamber 22. The sensor element 1 changes in frequency with mass change. The chamber 22 includes a gas introduction valve 27 for introducing a gas such as VOC, a nitrogen introduction valve 30, and an exhaust valve 28, and the inside of the chamber 22 can be controlled to a desired atmosphere. The gas introduction valve 27 is provided with a heater 29, and the gas introduced into the chamber 22 can be heated as necessary. The oscillator 23 is connected to a frequency detection counter 25 outside the chamber 22, and the frequency detection counter 25 is connected to a frequency change detection unit 26.

  When gas is introduced into the chamber 22 through the gas introduction valve 27, the sensor element 1 adsorbs the gas and changes its mass. Since the frequency changes with the mass change, the frequency change is measured by the frequency detection counter 25, and the frequency change is output by the frequency change detection unit 26 connected to the frequency detection counter 25. As the frequency detection counter 25, an Agilent 53131A universal frequency counter or the like can be used. As the frequency change detection unit 26, a computer device having as functions a detection unit that detects a physical change such as a frequency change and a recognition unit that obtains an adsorption characteristic from a detection result and recognizes a target substance is used.

  Although FIG. 2 shows the sensor 20 in which four sensor elements 1 are arranged, the sensor of the present invention has a function as a sensor by arranging at least one kind of sensor element. A plurality of sensor elements may be arranged in accordance with the detection target.

  As an example of an embodiment of the sensor of the present invention, it is preferable that the sensor element of the present invention and a detection means for detecting a physical change of the sensor element are provided. At least one, preferably two or more sensor elements of the present invention are arranged. The sensor element has different molecular recognition ability depending on the selection of organic substances constituting the sensitive film. This is due to the selectivity of organic matter. When the detection target is determined in advance, it can be detected by having at least one sensor element of the present invention, but by combining two or more sensor elements, the difference in molecular recognition ability of each sensor element Therefore, the detection accuracy can be increased.

  As another example of the sensor according to the present invention, the sensor element of the present invention, detection means for detecting a physical change of the sensor element, and the target substance is recognized by obtaining the adsorption characteristic from the detection result. And a recognition means. When detecting odors or breaths composed of multiple components, combine two or more sensor elements and detect the components that make up odors and breaths based on the difference in molecular recognition ability of each sensor element. To do. In order to detect components that make up odor and breath from the difference in molecular recognition ability, the adsorption characteristics such as the waveform of the frequency change of the vibration mass detection sensor and the mass change calculated from the frequency change are obtained. It is effective to use a method that recognizes the characteristics peculiar to the component. In this case, the sensor element using the calix resorcin allen-based composite material of the present invention may be combined with other sensor elements, or the sensor element using the calix resorcin allen-based composite material of the present invention having different molecular recognition capabilities. Two or more kinds may be combined.

  A sensor element having a sensitive film of [Chemical Formula 4], which is the calix resorcinarene composite material of the present invention, was prepared, and the frequency change was measured with an apparatus having the same principle as the sensor shown in FIG.

  FIGS. 3A to 3D are views for explaining a method for synthesizing the calixresorcinarene-based composite material of [Chemical Formula 4]. Hereinafter, the synthesis method will be described in the order of FIGS.

(A) 2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octaethoxycarbonylmethoxymethyl resorcis [4] arene (2,8,14,20 -Tetraundecyl-4,6,10,12,16,18,22,24-octaethyoxycarbonylmethylresor [[4] arene)

2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octahydroxyresorc [4] allene 0.50 g (4.52 × 10 ^-4 mol) and 5.0 ml of dry N, N-dimethylformamide (hereinafter referred to as “dryDMF” and also referred to as “dryDMF” in FIG. 3) were added and dissolved by heating to 60 ° C. To this, 1.13 g (8.14 × 10 ⁻⁴ mol) of potassium carbonate was slowly added, 0.923 ml (8.32 × 10 ⁻³ mol) of ethyl bromoacetate was further added, and the mixture was stirred at 80 ° C. for 20 hours. . Then, after returning to room temperature, extraction with diethyl ether was performed, and liquid separation was performed 3 times. After dehydration with magnesium sulfate, the solvent was removed under reduced pressure. Thereafter, silica gel chromatography (ethyl acetate: hexane = 2: 3) was performed. Further purified by preparative liquid chromatography and concentrated under reduced pressure to 2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octaethoxycarbonylmethoxymethyl resorci [4 I got Allen.

(B) 2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octacarboxymethylated resorcis [4] arene (2,8,14,20-tetradecyl) −4,6,10,12,16,18,22,24-octacarboxymethylatedresort [4] arene)

2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octaethoxycarbonylmethoxymethyl resorci [4] arene obtained in (a) 0.6 g ( 3.34 × 10 ⁻⁴ mol) was dissolved in 4 ml of ethanol, 0.28 g / 2.0 ml of a potassium hydroxide / ethanol solution (ethanol is indicated as EtOH in FIG. 3) was added, and the mixture was stirred and refluxed at 60 ° C. for 2 hours. The reaction was stopped by cooling in an ice bath, dissolved in water, and then reprecipitated by adding hydrochloric acid. This was extracted with diethyl ether, acidified twice with water and acidified with hydrochloric acid, and further separated once. After dehydration with magnesium sulfate, it was concentrated under reduced pressure to give 2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octacarboxymethylated resorci [4] arene. Obtained.

(C) 2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octa-N-allyl-2-hydroxyacetamidoresorc [4] arene (2, 8,14,20-tetradecyl-4,6,10,12,16,18,22,24-octa-N-allyl-2-hydroxyacetamicresorc [4] arene)

2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octacarboxymethylated resorci [4] arene obtained in (b) 0.5 g (3. 19 × 10 ⁻⁴ mol) was dissolved in dryDMF, a solution of 0.826 g (5.10 × 10 ⁻³ mol) of carbonyldiimidazole dissolved in 5 ml of dryDMF was added, and the mixture was stirred at room temperature for 18 hours. Thereafter, the reaction was carried out by heating at 45 ° C. for 3 hours. After the reaction, the reaction solution was returned to room temperature, naturally filtered, and separated three times with chloroform / water. After dehydration with magnesium sulfate, the solvent was removed under reduced pressure. Further purified by molecular sieve column chromatography and concentrated under reduced pressure to 2,8,14,20-tetraundecyl-4,6,10,12,16,18,22,24-octa-N-allyl-2-hydroxy. Acetamide resorci [4] arene (hereinafter referred to as calix resorcinarene derivative) was obtained.

(D) Synthesis of calixresorcinarene-based composite membrane 5.6 mg (3 × 10 ⁻⁶ mol) of calixresorcinarene derivative obtained in (c) and 15 μl of H-terminated polydimethylsiloxane (poly (siloxyxane, hydride terminated)) 2.4 × 10 ⁻⁵ mol) is dissolved in 300 μl of xylene, and after N ₂ bubbling, platinum (0) -1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solution (platinum (0 ) -1,3-divinyl-1,1,3,3-tetramethyl disiloxane complex solution) 21 μl was added and stirred and left at room temperature for 2 hours. Thereafter, the substrate was spin-coated on the substrate at a drop amount of 5 μl and a rotation speed of 4000 ppm, and heated at 100 ° C. for 2 hours. Further, it was washed with isopropyl alcohol and heated again at 100 ° C. for 1 hour to obtain a sensor element having a calixresorcinarene-based composite material represented by [Chemical Formula 4] as a sensitive film.
As the substrate, a quartz crystal resonator (manufactured by Tama Device Co., Ltd.) having a quartz base plate size of 8.7 mm and a gold electrode diameter of 5.0 mm was used.

  Although the sensor gas supply / discharge configuration of the sensor shown in FIG. 2 was partially changed using the sensor element, the frequency change was always measured in the state of gas flow using an apparatus based on the same principle as in FIG. First, the inside of the chamber in which the sensor element was installed was put into a nitrogen atmosphere, and then the gas to be measured was introduced. The gas was introduced for several minutes and the frequency change was measured. Thereafter, the gas in the apparatus was exhausted and replaced with nitrogen to return the frequency to the baseline. The frequency change was measured at room temperature.

The frequency change was measured by repeatedly introducing acetone and nitrogen. The amount of acetone introduced was increased by 100 ppm in the range of 500 ppm to 2000 ppm. The frequency change due to the introduction of acetone is shown in FIG.
The frequency change was measured by repeating the introduction of octane and nitrogen. The amount of octane introduced was increased by 100 ppm in the range of 500 ppm to 2000 ppm. FIG. 5 shows the frequency change due to the introduction of octane.
FIG. 6 shows frequency changes when 1000 ppm each of acetone, ethanol, toluene, and octane is introduced.

From FIG. 4, it was confirmed that the sensor element using the calixresorcinarene-based composite material of the present invention adsorbs acetone, which is a ketone molecule.
4 and 5, it can be seen that even when acetone or octane gas is introduced, the frequency changes at a substantially constant rate as the concentration increases, so that the introduced gas is adsorbed and desorbed with good reproducibility. It was.
From FIG. 6, even when a certain amount of gas is introduced, the frequency change amount differs for each gas type, so that the calix resorcinarene-based composite material of the present invention has selectivity for the gas type, other than the ketone molecule. It was confirmed that it is also useful as a sensitive film for recognizing VOCs.

In the above embodiment, using a calix resorcin arene-based composite material of C _11. However, other than this, as long as the gist of the present invention is not deviated, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

  DESCRIPTION OF SYMBOLS 1 ... Sensor element, 2 ... Board | substrate, 3 ... Sensitive membrane, 4 ... Gold electrode, 20 ... Sensor, 23 ... Transmitter, 24 ... Terminal, 25 ... Frequency detection counter, 26 ... Frequency change detection part

Claims (5)

A calix resorcin allen-based composite material represented by the following [Chemical Formula 1].

(In the above [Chemical Formula 1], R represents a linear alkyl group selected from C _2-12. N represents an integer selected from 1-500.) A sensor element in which a sensitive film is formed on a substrate,
The sensor film is made of a calix resorcin allen-based composite material represented by the following [Chemical Formula 2].

(In the above [Chemical Formula 2], R represents a linear alkyl group selected from C _2-12. N represents an integer selected from 1-500.)   The sensor element according to claim 2, wherein the substrate is made of gold, or is formed by forming a gold thin film on the surface of a Si-based material. A sensor element in which a sensitive film made of a calixresorcinarene-based composite material represented by the following [Chemical Formula 3] is formed on a substrate;
Detecting means for adsorbing a target material by the sensitive film and detecting a physical change of the sensor element due to the adsorbed target material;
A sensor characterized by comprising:

(In the above [Chemical Formula 3], R represents a linear alkyl group selected from C _2-12. N represents an integer selected from 1-500.)   The sensor according to claim 4, wherein the detection unit is a detection unit configured to detect a mass change due to the adsorbed target material as a frequency change of the vibration type mass detection sensor.

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