JP4904490B2 - Nanoparticle compound, metal ion detection method and removal method using this compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substance (compound) which interacts with a metal ion to change absorption characteristics in a visible light region, to provide a method for detecting a metal ion with the compound, and to provide a method for separating a metal ion with the compound. <P>SOLUTION: A compound represented by the general formula (1) : M<SB>10</SB>X<SB>4</SB>R<SB>12</SB>is disclosed. Therein, M is Cd or Zn; X is S or Se; R is one of formulas R<SP>1</SP>to R<SP>4</SP>in Fig; n<SB>1</SB>to n<SB>4</SB>in formulas R<SP>1</SP>to R<SP>4</SP>in Fig are each independently an integer of 1 to 10. The method for detecting a metal ion comprises making the above-mentioned compound to coexist in a test aqueous solution, and then detecting the presence or absence and/or concentration of the metal ion contained in the test aqueous solution. The method for separating a metal ion contained in an aqueous solution comprises mixing the aqueous solution with the above-mentioned compound and then separating the compound-metal ion complex formed in the aqueous solution from the aqueous solution. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a nanoparticle compound, and a method for detecting and removing a metal ion using the nanoparticle compound.

  Heavy metal ions such as mercury and lead are used in large amounts in daily life such as fluorescent lamps and automobile batteries, but even a small amount has a great impact on the human body and ecosystem. In order to investigate, it has become essential to develop a system capable of simple, rapid and sensitive detection. In the existing technology, expensive analyzers such as inductively coupled plasma (ICP) emission analysis are used, but complicated pretreatment such as desalting is necessary, and there are many problems such as being unsuitable for rapid analysis of many samples. From the viewpoint, there is a strong demand for the development of general-purpose and inexpensive spectrum equipment such as electron absorption and fluorescence, and simple chemical sensors using human color vision.

The present inventors have focused on nanoparticle compounds as candidates for the simple chemical sensor. As a nanoparticle compound, a nanoparticle having a luminescent property is known (Japanese Patent Publication No. 2002-536285, Patent Document 1). The nanoparticles are, for example, a composite of semiconductor particles such as CdS nanoparticles and a dendrimer. It is described that CdS nanoparticles can emit fluorescent signals and can be used for immunoassays, ELISA assays, DNA screenings, and the like.
Special table 2002-536285 gazette

The CdS nanoparticles are described as having a long-wavelength emission wavelength of more than 500 nm, and can be detected in the visible light region. However, the interaction with harmful metal ions such as Hg ²⁺ , Pb ^2+, etc., which is the object of the present invention is not described in Patent Document 1, and CdS nanoparticles are analyzed for these heavy metal ions. There is also no description of using it for.

  An object of the present invention is to provide means capable of rapidly detecting harmful heavy metal ions without special pretreatment by color change that can be detected by human vision or simple spectral spectroscopy.

  More specifically, providing a substance (compound) that interacts with a metal ion to change absorption characteristics in the visible light region, a method for detecting and separating a metal ion using such a compound, It is an object of the present invention.

The inventor of the present invention has focused on zinc sulfide and cadmium sulfide nanoparticles that exhibit unique optical properties as key substances. These fine particles are essentially insoluble in solvents, but by introducing a triethylene glycol chain on the surface, they can be dispersed uniformly in water in addition to organic solvents such as chloroform, benzene, methanol, and acetonitrile. It was. In addition, Hg ²⁺ , Pb ²⁺ , Ag ⁺ , Cu ²⁺ , Zn ²⁺ , Cd ²⁺ , Mn ²⁺ , Fe ³⁺ , Mn ²⁺ , Ni ² in aqueous solution, buffer solution, salt solution, acetonitrile It mixed with metal ions such as ⁺ and Co ^2+, and the responsiveness was evaluated from the change of electronic absorption spectrum and color.

As a result, the nanoparticle solution alone is colorless and transparent, and has no absorption at 400 nm or more (visible part). However, in response to Hg ²⁺ , Pb ²⁺ , Ag ⁺ , Cu ²⁺ specifically, absorption bands are induced in the visible region, and light brown for Hg ²⁺ , Pb ²⁺ , Cu ²⁺ ~ Yellow, Ag ⁺ is colored red. It was detectable up to about 10 ppm with the naked eye and up to about 0.5 ppm in the absorption spectrum. Regarding other metal ions, although some spectral changes such as Fe ³⁺ and Co ²⁺ were observed in the ultraviolet region, there was no significant change in the visible region. It selectively shows the response ability in the visible region. Further, in the presence of a salt compound (sodium chloride, buffer salt), an equivalent response activity is observed even in an organic solvent (acetonitrile), and pretreatment such as desalting is not particularly required. In addition, since chemical properties are similar to Hg ²⁺ and its homologous elements, Cd ²⁺ Zn ²⁺ , which is difficult to distinguish from Hg ²⁺ with conventional colorimetric and fluorescent sensors using chelate-type ligands, is completely It was revealed that there was no spectral change (solution color change) and a selective response to Hg ²⁺ . Based on such knowledge, the present invention has been completed.

［２］ｎ₁〜ｎ₃は３であり、ｎ₄は6である［１］に記載の化合物。
［３］被験水溶液に［１］または［２］に記載の化合物を共存させ、水溶液の色の変化から、被験水溶液に含まれる金属イオンの有無及び／又は濃度を検出することを含む、金属イオンの検出方法。
［４］金属イオンがHg²⁺, Pb²⁺, Ag⁺, またはCu²⁺である［３］に記載の検出方法。
［５］金属イオンの分析が、金属イオンの定量である［３］または［４］に記載の検出方法。
［６］水溶液の色の変化を３５０〜４５０ｎｍの波長範囲の吸光量を測定することで検出する［３］〜［５］のいずれかに記載の検出方法。
［７］水溶液の色の変化を４００ｎｍにおける吸光量を測定することで検出する［３］〜［５］のいずれか１項に記載の検出方法。
［８］水溶液に含まれる金属イオンを分離する方法であって、前記水溶液に［１］または［２］に記載の化合物を混合し、水溶液に形成した前記化合物と金属イオンとの錯体を、前記水溶液から分離することを含む、前記方法。
［９］錯体の水溶液からの分離を溶媒抽出により行う［８］に記載の方法。 [1] General formula (1): A compound represented by M ₁₀ X ₄ R ₁₂ .
[Wherein M is Cd or Zn;
X is S or Se,
R is any group represented by the following R ^{1 to} R ⁴ . In R ^{1 to} R ⁴ , n _{1 to} n ₄ are independently an integer of 1 to 10. ]

[2] The compound according to [1], wherein n _{1 to} n ₃ are 3 and n ₄ is 6.
[3] A metal ion comprising detecting the presence and / or concentration of a metal ion contained in a test aqueous solution from a change in the color of the aqueous solution by coexisting the compound according to [1] or [2] in the test aqueous solution Detection method.
[4] The detection method according to [3], wherein the metal ion is Hg ²⁺ , Pb ²⁺ , Ag ⁺ , or Cu ²⁺ .
[5] The detection method according to [3] or [4], wherein the analysis of metal ions is a quantification of metal ions.
[6] The detection method according to any one of [3] to [5], wherein a change in the color of the aqueous solution is detected by measuring an absorbance in a wavelength range of 350 to 450 nm.
[7] The detection method according to any one of [3] to [5], wherein a change in the color of the aqueous solution is detected by measuring an absorbance at 400 nm.
[8] A method for separating metal ions contained in an aqueous solution, wherein the compound according to [1] or [2] is mixed in the aqueous solution, and the complex of the compound and metal ions formed in the aqueous solution is Separating the aqueous solution.
[9] The method according to [8], wherein the complex is separated from the aqueous solution by solvent extraction.

According to the present invention, metal ions such as Hg ²⁺ , Pb ²⁺ , Ag ⁺ , and Cu ²⁺ can be selectively detected and quantified by changing the color of the test solution. Furthermore, according to the present invention, metal ions such as Hg ²⁺ , Pb ²⁺ , Ag ⁺ , and Cu ²⁺ can be selectively separated.

The present invention relates to a compound represented by the general formula (1): M ₁₀ X ₄ R ₁₂ .
In the formula, M is Cd or Zn.
X is S or Se.
R is any group represented by the following R ¹ to R ^4, in _{^{R 1 ~R 4, n 1 ~n}} 4 are independently an integer of 1 to 10.

The compound represented by the general formula (1) is obtained by synthesizing a compound in which the terminals (left end) of R ^{1 to} R ⁴ are thiol (SH) by a conventional method from commercially available raw materials, and the obtained thiol compound and CdS, It can be synthesized by reacting with a phenylthio compound of CdSe, ZnS, or ZnSe. Examples of the phenylthio compound include Cd ₁₀ S ₄ (SPh) ₁₂ , Cd ₁₀ Se ₄ (SPh) ₁₂ , Zn ₁₀ S ₄ (SPh) ₁₂ , and Zn ₁₀ Se ₄ (SPh) ₁₂ . In R ^{1 to} R ⁴ , n _{1 to} n ₄ are independently an integer of 1 to 10. n _{1 to} n ₃ are preferably independently 2 or 3, and more preferably 3. n ₄ is preferably an integer of 4 to 10, more preferably 5 to 7, and further preferably 6.

The above reaction scheme is an example where R is R ¹ (n ₁ = 3). The method for synthesizing the compound of the present invention will be specifically described with reference to this reaction scheme. Compound 2 is reacted with oxalic chloride to give acid chloride, and then reacted with 2- [2- (2-methoxyethoxy) ethoxy] ethylamine to give compound 3. Compound 2 can be synthesized according to the method described in RS Senger, VN Nemykin, P. Basu, New J. Chem., 2003, 27, 1115-1123. 2- [2- (2-methoxyethoxy) ethoxy] ethylamine is described in P. Pengo, S. Polizzi, M. Battagliarin, L. Pasquato, Paolo Scrimin, J. Mater. Chem., 2003, 13, 2471-2478. It can be synthesized according to the method described.

Compound 3 is reacted with NaBH ₄ to give compound 4. By adding Compound 4 to Cd ₁₀ S ₄ (SPh) ₁₂ suspended in an organic solvent, for example, acetonitrile, the target substance Cd ₁₀ S ₄ (SC ₆ H ₄ CONH (CH ₂ CH ₂ O) ₃ CH ₃ ) ₁₂ (1) is obtained.

The synthesis route (reaction formula) of the CdS cluster Cd ₁₀ S ₄ (SPh) ₁₂ is as follows.
1) Cd (NO ₃ ) ₂ + PhSH + NMe ₄ Cl → [Cd ₄ (SPh) ₁₀ ] (NMe ₄ ) ₂
2) [Cd ₄ (SPh) ₁₀ ] (NMe ₄ ) ₂ + S → [Cd ₁₀ S ₄ (SPh) ₁₆ ] (NMe ₄ ) ₄
3) [Cd ₁₀ S ₄ (SPh) ₁₆ ] (NMe ₄ ) ₄ → (Heating) → [Cd ₁₀ S ₄ (SPh) ₁₂ ]

Zn ₁₀ S ₄ (SPh) ₁₂ can be synthesized by using zinc nitrate instead of cadmium nitrate Cd (NO ₃ ) ₂ in the above reaction.

The synthesis route (reaction formula) of the CdSe cluster Cd ₁₀ Se ₄ (SPh) ₁₂ is as follows.
1) Cd (NO ₃ ) ₂ + PhSH + NMe ₄ Cl → [Cd ₄ (SPh) ₁₀ ] (NMe ₄ ) ₂
2) [Cd ₄ (SPh) ₁₀ ] (NMe ₄ ) ₂ + Se → [Cd ₁₀ Se ₄ (SPh) ₁₆ ] (NMe ₄ ) ₄
3) [Cd ₁₀ Se ₄ (SPh) ₁₆ ] (NMe ₄ ) ₄ → (Heating) → [Cd ₁₀ Se ₄ (SPh) ₁₂ ]

  In the above synthesis route, 1) 2) can be carried out according to the method described in I. G. Dance, A. Choy, M. L. Scudder, J. Am. Chem. Soc. 1984, 106, 6285. 3) CdS clusters can be synthesized using the thermal decomposition method described in W. E. Farneth, N. Herron, Y. Wang, Chem. Mater. 1992, 4, 916, and CdSe clusters can be synthesized in the same manner.

The compound of the present invention is considered to have a cluster structure, and the structure is shown below.

  The compound having the cluster structure has a semiconducting electronic structure similar to colloidal cadmium sulfide nanoparticles, and has unique absorption and emission characteristics derived therefrom. Colloidal cadmium sulfide nanoparticles are attracting attention as a molecular model of colloidal nanoparticles, and the compounds having the cluster structure of the present invention can also be classified as nanoparticles.

  The present invention relates to a method for detecting a metal ion, which comprises detecting the presence and / or concentration of a metal ion contained in a test aqueous solution from a change in the color of the aqueous solution by allowing the compound of the present invention to coexist in a test aqueous solution. .

  The aqueous test solution can be, for example, environmental water such as a river, a lake, or the sea. The method of the present invention is particularly effective for analysis of seawater because it does not interfere with analysis even when a large amount of salt coexists. Moreover, the aqueous solution obtained by extracting and filtering soil, sludge, etc. can be used as the test aqueous solution.

The concentration of the compound of the present invention in the test aqueous solution is determined so that the complex is formed to such an extent that the absorption of the complex formed by the compound of the present invention and the metal ion in the test aqueous solution can be discriminated with the naked eye or measured with a spectrophotometer. It is appropriate to make adjustments. Although there is a difference depending on the type of complex, if it is a spectrophotometer, 5.0 x 10 ^-6 mol / L can be detected sufficiently, and with the naked eye it is 10 ^-5 to 10 ^-4 mol, which is one order higher than that. If the concentration is / L, the detection is sufficient.

Therefore, for measurement with a spectrophotometer, the concentration of the compound of the present invention in the aqueous test solution is suitably in the range of, for example, 5 × 10 ⁻⁶ to 2 × 10 ⁻⁵ mol / L. By setting the concentration of the compound of the present invention in the test aqueous solution within this range, heavy metal ions on the order of several ppm can be detected.

In the detection method of the present invention, for example, Hg ²⁺ , Pb ²⁺ , Ag ⁺ , and Cu ²⁺ can be detected as metal ions.

  The aqueous solution containing the compound of the present invention is colorless and transparent when these compounds are present alone in the aqueous solution. On the other hand, the aqueous solution containing any of the above metal ions and the compound of the present invention shows coloration in the wavelength range of 350 to 450 nm. Therefore, the presence or absence of metal ions contained in the test aqueous solution can be detected from the change in the color of the aqueous solution. Furthermore, the metal ion concentration contained in the test aqueous solution can be quantified from the change in the color of the aqueous solution. In this case, the metal ion concentration can be quantified by measuring the amount of light absorption in this wavelength range. More preferably, the metal ion concentration can be quantified by measuring the absorbance of the aqueous solution at 400 nm. In this case, a calibration curve between the metal ion concentration in the aqueous solution and the absorbance is prepared in advance. Thus, in the detection method of the present invention, metal ions in an aqueous solution can be quantified.

  Furthermore, this invention includes the method of isolate | separating the metal ion contained in aqueous solution. In this method, the compound of the present invention is mixed with an aqueous solution containing a metal ion to form a complex of the metal ion contained in the aqueous solution and the compound of the present invention. The formed complex is then separated from the aqueous solution. The complex can be formed by simply mixing the compound of the present invention in an aqueous solution containing metal ions at room temperature.

  Separation of the formed complex from the aqueous solution can be performed, for example, by solvent extraction. For example, in the solvent extraction, when chloroform is used as a solvent, the complex moves to the solvent side. By using a sufficient amount of the compound of the present invention to capture the metal ions contained in the aqueous solution, the metal ions in the aqueous solution can be removed.

Utilizing the characteristics described above, the compound (nanoparticles) of the present invention can be used for simple colorimetric sensing of heavy metal ions, particularly highly toxic Hg ²⁺ and Pb ²⁺ . In particular, characteristics such as 1) not using large and expensive analytical instruments, 2) no pre-treatment such as desalting, 3) selective response to similar metal ions, etc. It can be expected that rapid screening by “in situ analysis” of heavy metal ions contained in a sample will be possible.

In order to further improve the sensitivity, it is also possible to assemble with a concentration part and a simple spectrophotometer. In combination with these, there is a possibility that it can be used as a kit that can be used without specialized knowledge. As mentioned earlier, this compound (cluster) is also soluble in chloroform and benzene, which are immiscible with water. In that case, Pb ²⁺ and Hg ²⁺ ions dissolved in water are efficiently dissolved in these organic solvents. Can be extracted (confirmed up to about 10 times in molar ratio). Therefore, this cluster may be used as a material for removing heavy metal ions in water.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1

4,4'-dithiodi (N- (2- (2- (2-methoxyethoxy) ethoxy) ethyl) benzamide (3)
4, 4'-dithiodibenzoic acid suspended in dry THF (10 ml) containing 2-3 drops of DMF [RS Senger, VN Nemykin, P. Basu, New J. Chem., 2003, 27, 1115-1123] (2, 0.400 g, 1.30 mmol) was added dropwise oxalic chloride (1.5 mL, 17 mmol) under nitrogen at 0 ° C. After stirring at room temperature for 5 hours, the resulting yellow homogeneous solution was dried under vacuum to give the acid chloride as a viscous yellow solid. This solid was dissolved in dehydrated dichloromethane (10 mL), and 2- [2- (2-methoxyethoxy) ethoxy] ethylamine [P. Pengo, S. Polizzi, M. Battagliarin, L. Pasquato, Paolo Scrimin, J Mater. Chem., 2003, 13, 2471-2478] (0.630 g, 3.86 mmol) in a solution of dry dichloromethane / triethylamine (12 mL, 5/1 v / v) at 0 ° C. and then slowly at room temperature The mixture was stirred again overnight. After distilling off volatile components under reduced pressure, the crude product was separated and purified using a silica gel column (Kanto Chemical Co., Silica Gel 60N, developing solvent: chloroform / methanol = 10/1), and 4,4′-dithiodi (N -(2- (2- (2-methoxyethoxy) ethoxy) ethyl) benzamide (3) was obtained as a yellow oil (0.81 g, 100%).

¹ H NMR δ (400 MHz; CDCl ₃ ) 7.75 (4H, d, Ar 3-H, 5-H), 7.52 (4H, d, Ar 2-H, 6-H), 6.84 (2H, br, NH ), 3.70-3.60 (20H, m, CH ₂ (OC ₂ H ₄ ) ₃ ), 3.51 (4H, m, NCH ₂ ), 3.30 (6H, s, OCH ₃ )

N- (2- (2- (2-methoxyethoxy) ethoxy) ethyl) -4-mercaptobenzamide (4)
To a solution of 2 (1.30 mmol) in dry THF / EtOH (30/30 mL), NaBH ₄ (0.52 g, 14 mmol) was added little by little with stirring at 0 ° C., and the mixture was stirred overnight at room temperature. The residue obtained by distilling off the volatile components under reduced pressure was dissolved in water (10 mL), acidified with 1N hydrochloric acid, and extracted with ethyl acetate. The organic phase was dried over MgSO ₄ and evaporated under reduced pressure to give N- (2- (2- (2-methoxyethoxy) ethoxy) ethyl) -4-mercaptobenzamide (4) as a yellow oily substance. Obtained (0.74 g, 95%). This substance was directly subjected to the reaction without further purification.

¹ H NMR δ (400 MHz; CDCl ₃ ) 7.68 (2H, d, Ar 2- and 6-H), 7.28 (2H, d, Ar 3- and 5-H), 6.84 (1H, br, NH), 3.70-3.60 (10H, m, CH ₂ (OC ₂ H ₄ ) ₃ ), 3.56 (1H, s, SH), 3.53 (2H, m, NCH ₂ ), 3.33 (3H, s, OCH ₃ )

Cd ₁₀ S ₄ (SC ₆ H ₄ CONH (CH ₂ CH ₂ O) ₃ CH ₃ ) ₁₂ (1a):
4 (1.40 g, 4.7 mmol) was added to Cd ₁₀ S ₄ (SPh) ₁₂ (200 mg, 0.078 mmol) suspended in dry acetonitrile (20 mL), and the mixture was stirred at room temperature for 20 hours. Volatile components were removed from the obtained homogeneous solution under reduced pressure, and the residue was washed with hexane to remove the benzenethiol produced, and further washed with diethyl ether / tetrahydrofuran (4/1 v / v). Excess charge 4 was removed. The obtained solid was dissolved in benzene and freeze-dried to obtain 1a as a deliquescent yellow solid (300 mg, 80%).
Elemental analysis: calcd (%) for Cd ₁₀ S ₄ (C ₁₄ H ₂₀ NO ₄ S) ₁₂ (H ₂ O) ₆ (C ₁₆₈ H ₂₅₂ Cd ₁₀ N ₁₂ O ₅₄ S ₁₆ ): C 40.83, H 5.14, N 3.40, S 10.38; found C 40.78, H 4.97, N 3.35, S 10.51.

Cd ₁₀ Se ₄ (SC ₆ H ₄ CONH (CH ₂ CH ₂ O) ₃ CH ₃ ) ₁₂ (1b)
It was synthesized by reacting Cd ₁₀ Se ₄ (SPh) ₁₂ and 7 in the same manner as the synthesis of 1a (yield: 74%). In the infrared absorption spectrum, it was confirmed that absorption at 690,735 cm ⁻¹ derived from the phenyl group of Cd ₁₀ Se ₄ (SPh) ₁₂ disappeared.

Zn ₁₀ S ₄ (SC ₆ H ₄ CONH (CH ₂ CH ₂ O) ₃ CH ₃ ) ₁₂ (1c)
It was synthesized by reacting Zn ₁₀ S ₄ (SPh) ₁₂ and 7 in the same manner as the synthesis of 1a (yield: 76%). The purity was 95% or more. In the infrared absorption spectrum, it was confirmed that absorption at 690,735 cm ⁻¹ derived from the phenyl group of Zn ₁₀ S ₄ (SPh) ₁₂ disappeared.
Elemental analysis: calcd (%) for Zn ₁₀ S ₄ (C ₁₄ H ₂₀ NO ₄ S) ₁₂ (C ₁₆₈ H ₂₄₀ Zn ₁₀ N ₁₂ O ₅₄ S ₁₆ ): C 46.25, H 5.54, N 3.85, S 11.76; found C 44.11, H 5.05, N 3.13, S 13.00

Example 2

4,4'-dithiodi (N- (2- (2- (2-methoxyethoxy) ethoxy) ethyl) benzoate (6)
Synthesis was performed in the same manner as in Compound 3 of Example 1, using 2- [2- (2-methoxyethoxy) ethoxy) ethanol as a raw material instead of 2- [2- (2-methoxyethoxy) ethoxy) ethylamine. Went (yield: ~ 100%).
¹ H NMR δ (400 MHz; CDCl ₃ ) 7.98 (4H, d, Ar 3-H, 5-H), 7.52 (4H, d, Ar 2-H, 6-H), 4.45 (4H, t, COOCH ₂ ), 3.81 (4H, t, CH ₂ O), 3.75-3.50 (16H, m, CH ₂ (OC ₂ H ₄ ) ₃ ), 3.35 (6H, s, OCH ₃ )

2- (2- (2-methoxyethoxy) ethoxy) ethyl 4-mercaptobenzoate (7)
Compound (6) was synthesized by reduction with NaBH ₄ in TH / EtOH in the same manner as Compound 4 of Example 1 (yield: 97%).
¹ H NMR δ (400 MHz; CDCl ₃ ) 7.89 (2H, d, Ar 3-H, 5-H), 7.27 (2H, d, Ar 2-H, 6-H), 4.44 (2H, t, COOCH ₂ ), 3.81 (2H, t, CH ₂ O), 3.75-3.50 (9H, m, CH ₂ (OC ₂ H ₄ ) ₃ , SH), 3.35 (3H, s, OCH ₃ )

Cd ₁₀ S ₄ (SC ₆ H ₄ COO (CH ₂ CH ₂ O) ₃ CH ₃ ) ₁₂ (5):
It was synthesized by reacting Cd ₁₀ S ₄ (SPh) ₁₂ and 7 in the same manner as the synthesis of 1 (yield: 85%). The purity was 95% or more. In the infrared absorption spectrum, it was confirmed that absorption at 690,735 cm ⁻¹ derived from the phenyl group of Cd ₁₀ S ₄ (SPh) ₁₂ disappeared.
Elemental analysis: calcd (%) for Cd ₁₀ S ₄ (C ₁₄ H ₁₉ O ₅ S) ₁₂ (C ₁₆₈ H ₂₂₈ Cd ₁₀ O ₆₀ S ₁₆ ): C 41.65, H 4.74, S 10.59; found C 40.18, H 4.28 , S 12.32

Example 3

S-acetyl-1-mercapto-2- (2- (2- (2-methoxyethoxy) ethoxy) ethylcarbamoyl) ethane (9)
500 mg 2-thioacetylpropionic acid (1, 0.500 g, 3.37 mmol), EDC (671 mg, 3.50 mmol), HOBt (54 mg, 0.35 mmol) in dehydrated CHCl ₂ solution at 0 ° C under nitrogen [2- (2-Methoxyethoxy) ethoxy) ethylamine (0.570 g, 3.50 mmol) was added dropwise. After stirring at room temperature for 12 hours, the reaction solution was washed with 1N HCl aq. The organic phase was dried over MgSO 4 and evaporated under reduced pressure to give a yellow oily substance 4 (0.800 g, 81%). ¹ H NMR δ (400 MHz; CDCl ₃ ) 6.18 (1H, br, NH), 3.70-3.42 (12H, m, CH ₂ (OC ₂ H ₄ ) ₃ ), 3.38 (3H, s, OCH ₃ ), 3.15 (2H, t, SCH ₂ ), 2.49 (2H, t, CH ₂ CO), 2.32 (3H, t, CH ₃ COS)

N- (2- (2- (2-methoxyethoxy) ethoxy) ethyl) -3-mercaptopropanamide (10)
According to the literature [T. Zheng, M. Burkart, DE Richardson, Tetrahedron. Lett., 1999, 40, 603-606], compound (9) was synthesized by treatment with NaOH in acetone solution and deacetylation ( yield: ~ 100%).
¹ H NMR δ (400 MHz; CDCl ₃ ) 6.32 (1H, br, NH), 3.70-3.42 (12H, m, CH ₂ (OC ₂ H ₄ ) ₃ ), 3.39 (3H, s, OCH ₃ ), 2.81 (2H, q, SCH ₂ ), 2.50 (2H, t, CH ₂ CO), 1.63 (1H, t, SH)

Cd ₁₀ S ₄ (SC ₂ H ₄ CONH (CH ₂ CH ₂ O) ₃ CH ₃ ) ₁₂ (8):
Synthesized by reacting Cd ₁₀ S ₄ (SPh) ₁₂ and 10 in the same manner as the synthesis of compound 1 of Example 1 (yield: 78%)
Elemental analysis: calcd (%) for Cd ₁₀ S ₄ (C ₁₀ H ₂₀ NO ₄ S) ₁₂ (C ₁₂₀ H ₂₄₀ Cd ₁₀ N ₁₂ O ₄₈ S ₁₆ ): C 33.86, H 5.68, N 3.95, S 12.05; found C 33.48, H 5.31, N 3.46, S 12.63

Example 4

[CH ₃ (OC ₂ H ₄ ) _n OC ₆ H ₄ S] ₂ [T. Fukushima, A. Kosaka, Y. Ishimura, T. Yamamoto, T. Takigawa, N. Ishii, T. Aida, science, 2004, 304, 1481-1483] (12)
4, 2'-dihydroxyphenyl disulfide (1.00 g, 3.99 mmol) and CH ₃ (OC ₂ H ₄ ) _n OTs (n _av = 7.25, 6.05 g) in DMF (10 mL) solution with K ₂ CO ₃ (2.5 g, 18 mmol) was added, heated to 80 ^° C. and stirred overnight. Thereafter, DMF was removed under heating under reduced pressure (˜70 ° C.), and the residue was dissolved in water (50 mL) and extracted with CH ₂ Cl ₂ . After the organic phase is dried over Na ₂ SO ₄ , volatile components are distilled off under reduced pressure, and then the crude product is separated using a silica gel column (Kanto Chemical, Silica Gel 60N, developing solvent: chloroform / methanol = 10/1). Purification gave [CH ₃ (OC ₂ H ₄ ) _n OC ₆ H ₄ S] ₂ as a yellow oil (4 g, ˜100%).
¹ H NMR δ (400 MHz; CDCl ₃ ) 7.36 (4H, d, Ar 3-H, 5-H), 6.84 (4H, d, Ar 2-H, 6-H), 4.10 (4H, t, OCH ₂ ), 3.84 (4H, t, CH ₂ O), 3.75-3.50 (60H, m, CH ₂ (OC ₂ H ₄ ) _n ), 3.36 (6H, s, OCH ₃ )

CH ₃ (OC ₂ H ₄ ) _n OC ₆ H ₄ SH (13)
Compound (12) was synthesized by reduction with NaBH ₄ in TH / EtOH (yield: ˜100%) in the same manner as in ₄ .
¹ H NMR δ (400 MHz; CDCl ₃ ) 7.24 (2H, d, Ar 3-H, 5-H), 6.81 (2H, d, Ar 2-H, 6-H), 4.08 (2H, t, OCH ₂ ), 3.84 (2H, t, CH ₂ O), 3.75-3.58 (30H, m, CH ₂ (OC ₂ H ₄ ) _n ), 3.36 (3H, s, OCH ₃ ), 3.35 (1H, s, SH )

Cd ₁₀ S ₄ (SC ₆ H ₄ O (C ₂ H ₄ O) _n CH ₃ ) ₁₂ [n _av = 6] (11):
Synthesized by reacting Cd ₁₀ S ₄ (SPh) ₁₂ and 13 in the same way as the synthesis of 1 (yield: 82%)
Elemental analysis: calcd (%) for C ₂₂₈ H ₃₇₂ Cd ₁₀ O ₉₉ S ₁₆ (n = 6): C 44.94, H 6.15, S 8.41; found found C 44.74, H 6.02, S 9.17

Example 5
To a nanoparticle (concentration = 6.7 x 10-6 (mol / L)) dissolved in ion-exchanged water or HEPES buffer, add a certain amount of an aqueous solution of metal salt (chloride, nitrate, etc.) at room temperature, and obtain an absorption spectrum. taking measurement. Evaluation was made by comparing with a blank spectrum.

<Results and evaluation>
FIG. 1 shows a typical change in absorption spectrum when HgCl ₂ is added to compound 1a. Initially, there was no absorption in the visible region of 400 nm or more, but with the addition of metal ions, tailing was observed on the long wavelength (visible region) side, resulting in a change from colorless and transparent to light brown to yellow. In the upper right plot, 400 nm is picked up as a coloring index, and the absorbance is plotted against the metal ion concentration. Using an instrument (spectrophotometer) instead of the naked eye indicates that sensitivity can be increased and quantification is possible.

The results when AgNO ₃ or Cu (NO ₃ ) ₂ is added instead of HgCl ₂ are shown in FIGS. Moreover, the result at the time of replacing the compound 1a with the compound 1b, 1c, 5 or 8 is shown to FIGS. In either case, initially there is no absorption in the visible region of 400 nm or more, but with the addition of metal ions, tailing will be seen on the long wavelength (visible region) side, resulting in a change from colorless and transparent to light brown to yellow did. In addition, the plot in the upper right of each figure is obtained by picking up 400 nm as a coloring index and plotting the absorbance with the metal ion concentration. Using an instrument (spectrophotometer) instead of the naked eye indicates that sensitivity can be increased and quantification is possible.

Example 6
How to remove harmful heavy metal ions
Compound 1a (50 mg) was added to an aqueous solution (50 mL) of HgCl ₂ (14 mg) at room temperature to form a complex, and chloroform (50 mL) and saturated brine (50 mL) were added thereto. Separation with a separatory funnel extracted the 1a-Hg complex from the aqueous phase to the chloroform phase, resulting in the removal of mercury from the water.

  The present invention is useful in chemical analysis, environmental fields, and the like.

Absorption spectrum change between compound 1a and HgCl ₂ Absorption spectrum change between compound 1a and AgNO ₃ Absorption spectrum change between compound 1a and Cu (NO ₃ ) ₂ Absorption spectrum change between compound 1b and HgCl ₂ Absorption spectrum change between compound 1c and HgCl ₂ Absorption spectrum change between compound 5 and HgCl ₂ Absorption spectrum change between compound 5 and Cu (NO ₃ ) ₂ Absorption spectrum change between compound 8 and HgCl ₂

Claims (9)

Formula (1): M ₁₀ X ₄ compound represented by R _12.
[Wherein M is Cd or Zn;
X is S or Se,
R is any group represented by the following R ^{1 to} R ⁴ . In R ^{1 to} R ⁴ , n _{1 to} n ₄ are independently an integer of 1 to 10. ]

The compound according to claim 1, wherein n _{1 to} n ₃ are 3 and n ₄ is 6. A method for detecting a metal ion, comprising: coexisting the compound according to claim 1 or 2 in a test aqueous solution, and detecting the presence and / or concentration of the metal ion contained in the test aqueous solution from a change in the color of the aqueous solution. The detection method according to claim 3, wherein the metal ion is Hg ²⁺ , Pb ²⁺ , Ag ⁺ , or Cu ²⁺ . The detection method according to claim 3 or 4, wherein the analysis of metal ions is determination of metal ions. The detection method according to any one of claims 3 to 5, wherein a change in the color of the aqueous solution is detected by measuring an absorbance in a wavelength range of 350 to 450 nm. The detection method according to any one of claims 3 to 5, wherein a change in the color of the aqueous solution is detected by measuring an absorbance at 400 nm. A method for separating metal ions contained in an aqueous solution, wherein the compound according to claim 1 or 2 is mixed with the aqueous solution, and the complex of the compound and metal ions formed in the aqueous solution is separated from the aqueous solution. Said method. The method according to claim 8, wherein the complex is separated from the aqueous solution by solvent extraction.

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