A fluorescent probe for detecting trace chloride ions, and a preparation method and application thereof

Abstract

The application discloses a fluorescent probe for trace chloride ion detection and a preparation method and application thereof, and belongs to the field of semiconductor material analysis and detection. + The fluorescent probe is B2 fluorescent probe (thiophene bridged double benzimidazole structure), which can form a 1:1 complex with Ag + The B2-Ag ‑ Complex further exhibits a fluorescence recovery response to Cl ‑ The concentration of Cl is in a good linear relationship within the range of 0-80 muM, and the detection limit is 0.0411 ppm. The B2 probe is applied to photoresist, and matrix interference can be effectively reduced through 20 times dilution, so that rapid and direct quantitative detection of chloride ions in original liquid photoresist samples before spin coating is successfully realized. Without complex pretreatment such as extraction, burning and column passing, the B2 probe has high sensitivity, strong selectivity and simple operation, and is suitable for online quality control of trace chloride ions in photoresist, electronic chemicals and high-purity solvents.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor material analysis and detection, specifically relating to a fluorescent probe for the detection of trace chloride ions, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] As a core functional material in integrated circuit manufacturing, the purity of photoresist has a decisive impact on chip yield and reliability. With technology nodes continuously shrinking to the nanoscale, the detection and control of trace impurity ions in photoresist has become a key technological challenge for the semiconductor industry.

[0004] Trace amounts of chloride ions in photoresist can easily cause electrochemical corrosion of metal circuits, interface contamination, and decreased device reliability. Traditional chloride ion detection methods mainly rely on ion chromatography, which has drawbacks such as complex pretreatment, long processing time, expensive instruments, and difficulty in online detection, failing to meet the rapid quality control requirements of semiconductor mass production lines. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a fluorescent probe for the detection of trace chloride ions, its preparation method, and its application.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a fluorescent probe for the detection of trace chloride ions, wherein the fluorescent probe is bis(benzimidazol-2-yl)thiophene-2,5-diamine, denoted as B2, and its structural formula is shown below: .

[0007] Secondly, the present invention provides a method for preparing the above-mentioned fluorescent probe for trace chloride ion detection, comprising the following steps: Thiophene-2,5-dicarboxaldehyde was reacted with 4-nitro-o-phenylenediamine in an organic solvent by heating to obtain intermediate B1; Intermediate B1 was reacted with 4,4′-bipyridine and B2(OH)4 at room temperature to reduce the nitro group to an amino group, yielding the target product B2.

[0008] Thirdly, the present invention provides the application of the fluorescent probe for trace chloride ion detection described above or the fluorescent probe for trace chloride ion detection prepared by the above preparation method in the detection of trace chloride ions.

[0009] Fourthly, the present invention provides a fluorescence detection method for chloride ions in solution, characterized by comprising the following steps: The sample to be tested was combined with the above-mentioned fluorescent probe and Ag. + Mix and incubate; The fluorescence intensity of the system at 550 nm was measured at an excitation wavelength of 420 nm. According to Cl - The standard curve of concentration versus fluorescence recovery intensity was used to calculate the Cl concentration in the sample. - The concentration.

[0010] Fifthly, the present invention provides a rapid detection method for chloride ions in photoresist, comprising: Dilute the photoresist sample with an organic solvent; add the above-mentioned fluorescent probe and Ag. + Forming probe-Ag + Complexes were analyzed, and fluorescence recovery intensity was measured.

[0011] One or more of the above technical solutions have the following advantages or beneficial effects: 1. The fluorescent probe for trace chloride ion detection is a B2 fluorescent probe (thiophene-bridged bisbenzimidazole structure), which can react with Ag. + A 1:1 complex is formed and fluorescence quenching occurs, B2-Ag + The complex further affects Cl - It exhibits a fluorescence recovery response, and the fluorescence recovery intensity is related to Cl. - The concentration showed good linearity in the range of 0–80 μM, and the detection limit was 0.0411 ppm.

[0012] 2. The B2 probe was applied to DNQ-phenolic resin-based positive photoresists (including the commercially available SPR955-CM photoresist) and epoxy-based negative photoresist SU-8 2000.5. A 20-fold dilution effectively reduced matrix interference, successfully achieving rapid and direct quantitative detection of chloride ions in the original liquid photoresist samples before spin coating. This method eliminates the need for complex pretreatment processes such as extraction, incineration, and column chromatography, offering high sensitivity, strong selectivity, and ease of operation. It is suitable for online quality control of trace chloride ions in photoresists, electronic chemicals, and high-purity solvents. Specifically: (1) High sensitivity: B2 probe to Cl - The detection limit is as low as 0.0411 ppm, which is about 2.6 times more sensitive than the monobenzimidazole probe A2 (0.109 ppm), and can meet the semiconductor industry's needs for the detection of trace chloride ions (sub-ppm level).

[0013] (2) High selectivity: B2 probe is effective against Ag + and Cl -It exhibits excellent selective recognition ability for common metal ions (Cu). 2+ Mn 2+ Zn 2+ K + Fe 2+ Ni 2+ Mg 2+ Na + Ca 2+ Cd 2+ Pb 2+ ) and anions (ClO) - NO3 - ,Br - SO4² - I - F - PO4³ - HCO3 - AcO - None of them produced significant interference.

[0014] (3) Fast response: B2 probe to Ag + The fluorescence quenching response can be completed within 50 seconds, for Cl - The fluorescence recovery response stabilizes within 6 minutes, making it suitable for rapid detection.

[0015] (4) Strong resistance to matrix interference: In a photoresist sample diluted 20 times, the B2 probe can still effectively respond to Cl - It has been successfully applied to the direct quantitative detection of chloride ions in DNQ-phenolic resin positive photoresist (commercial SPR955-CM) and epoxy negative photoresist (SU-82000.5).

[0016] (5) Simple operation and no complicated pretreatment required: Compared with the water extraction and solid phase extraction required by ion chromatography, the fluorescent probe method of the present invention only requires diluting the photoresist with PGMEA and then directly adding the probe and Ag. + It can be detected through incubation, and is simple, fast, and low-cost to operate. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 Ag based on ligand substitution mechanism + -Benzimazole complex chloride ion probe.

[0019] Figure 2 This is a design and synthesis route diagram for A-series and B-series fluorescent probes.

[0020] Figure 3 The B2 probe responds to different concentrations of Ag + fluorescence spectrum and B2-Ag + The fluorescence intensity of the complex and Cl - Concentration changes and linear fitting curves; where a represents the response of the B2 probe to different concentrations of Ag. + Fluorescence spectrum (0 ~ 40 μM); b is B2-Ag + The fluorescence intensity of the complex and Cl - (0 ~ 80 μM) concentration variation and linear fitting curve, working curve: λ ex / λ em = 420 / 550 nm.

[0021] Figure 4 For B2 probe and B2-Ag + The fluorescence intensity of the complex in PGMEA changes over time (s); where a represents the fluorescence intensity of the B2 probe after the addition of Ag to PGMEA. + The curve showing the change in fluorescence intensity over time (s); b represents B2-Ag. + The fluorescence intensity of the complex in PGMEA changes over time (min) after the addition of Cl-.

[0022] Figure 5 B2-Ag + Complexes on Cl in different photoresist samples - The fluorescence response spectrum; where a is SPR955-CM photoresist; b is SU-8 2000.5 photoresist; working curve: λ ex / λ em =420 / 515 nm; λ ex / λ em =420 / 531nm.

[0023] Figure 6 For B2 probe and B2-Ag + Fluorescence responses of the complexes to different metal ions; where a represents the fluorescence response of the B2 probe (20.0 μM) to different metal ions (40.0 μM) in PGMEA; b represents the fluorescence response of B2-Ag. + Fluorescence response of the complex to different ions (80.0 μM) in PGMEA.

[0024] Figure 7 For B2 probe and B2-Ag + The complex responds to Ag in different solvents +The fluorescence spectrum at (40 μM) is shown; where a represents the response of the B2 probe (20.0 μM) to Ag in different solvents. + Fluorescence spectrum at (40 μM); b represents B2-Ag + Complexes respond to Cl in different solvents - Fluorescence spectrum at (80 μM).

[0025] Figure 8 To determine the B2-Ag content in a buffer system with a pH range of 4.0 to 9.0. + Complex (B2 is 20.0 μM, Ag) + (40.0 μM) and the addition of Cl - The fluorescence intensity change at 550 nm after (80.0 μM). Working curve: λex / λem = 420 / 550nm.

[0026] Figure 9 For B2 probe and B2-Ag + Adding Ag to the complex + or Cl - The curve showing the change in fluorescence intensity over time; where a represents the change in fluorescence intensity of the B2 probe after the addition of Ag to PGMEA. + The curve showing the change in fluorescence intensity over time; b represents B2-Ag. + The complex was added to PGMEA with Cl - The curve showing the change in fluorescence intensity over time. Detailed Implementation

[0027] To address the problems of existing methods for detecting trace chloride ions in photoresists, such as complex operation, insufficient sensitivity, and significant matrix interference, it is of great significance to develop a rapid, sensitive, simple, and direct chloride ion detection technology for liquid photoresists. Therefore, this invention provides a chloride ion fluorescent probe, its preparation method, and its application in chloride ion detection in photoresists.

[0028] The fluorescent probe provided by this invention is an amino-substituted bisbenzimidazole structure for subsequent silver ion detection. It may form an N-Ag-N coordination configuration close to 180°, exhibiting higher stability. Therefore, compared with monobenzimidazole probes (A1-A3), this probe demonstrates superior detection performance and a lower detection limit. Furthermore, the amino group also significantly affects the detection limit. Compared with the nitro-substituted bisbenzimidazole probe B1, probe B2 has a lower detection limit, possibly because the nitro group, as an electron-withdrawing group, weakens the interaction between the nitrogen atom in the benzimidazole and Ag. + The coordination between them affects the final detection limit of chloride ions.

[0029] In one typical embodiment, the present invention provides a fluorescent probe for the detection of trace chloride ions, wherein the fluorescent probe for the detection of trace chloride ions is bis(benzimidazol-2-yl)thiophene-2,5-diamine, denoted as B2.

[0030] Its structural formula is shown below: .

[0031] B2 has an excitation wavelength of 420 nm and an emission wavelength of 550 nm.

[0032] Furthermore, the fluorescent probe is activated by silver ions (Ag) + ) mediates the achievement of chloride ion (Cl) - Indirect fluorescence detection of B2 probe, the detection mechanism is: B2 probe reacts with Ag + The formation of a 1:1 complex leads to fluorescence quenching, Cl - With Ag + Competitive complexation occurs, causing the fluorescence of the B2 probe to recover.

[0033] In one typical embodiment, the present invention provides a method for preparing the above-mentioned fluorescent probe for trace chloride ion detection, comprising the following steps: Thiophene-2,5-dicarboxaldehyde was reacted with 4-nitro-o-phenylenediamine in an organic solvent by heating to obtain intermediate B1; Intermediate B1 was reacted with 4,4′-bipyridine and B2(OH)4 at room temperature to reduce the nitro group to an amino group, yielding the target product B2.

[0034] In some embodiments of this implementation, in the preparation of intermediate B1, the molar ratio of thiophene-2,5-dicarboxaldehyde to 4-nitro-o-phenylenediamine is (2~10):(5~15), preferably (4~6):(8~12). This step is a condensation cyclization reaction of an aromatic dialdehyde and an o-diamine, with a molar ratio of 1:2 being optimal.

[0035] Furthermore, the organic solvent includes dimethyl sulfoxide. The mass-to-volume ratio of thiophene-2,5-dicarboxaldehyde to the organic solvent is (2~10):(10~30), preferably (4~6):(15~25), in g / mL.

[0036] Furthermore, the heating reaction conditions are: 120~150℃ (specifically 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃) for 4~10 h (specifically 4h, 5h, 5.5h, 6h, 6.5h, 7h, 8h, 9h, 10h), preferably 125~135℃ for 5~7 h.

[0037] Furthermore, the heating reaction also includes precipitation, filtration, washing, and purification.

[0038] In some embodiments of this implementation, the molar ratio of intermediate B1, 4,4′-bipyridine, and B2(OH)4 in the preparation of target product B2 is (1~5):(1~5):(20~30), preferably (2~3):(2~3):(25~30). Further, the mixture is stirred at room temperature for 5~30 min, preferably 5~15 min. During the reaction, TLC is continuously performed, and the stability or time range is reasonably controlled by observing the depth of the starting material and product spots.

[0039] Furthermore, after stirring at room temperature, the process also includes extraction, washing with water, drying, rotary evaporation, and purification.

[0040] In one typical embodiment, the present invention provides the application of the fluorescent probe for trace chloride ion detection described above or the fluorescent probe for trace chloride ion detection prepared by the above preparation method in the detection of trace chloride ions.

[0041] It is preferably used in the detection of trace chloride ions in photoresists, electronic chemicals, and high-purity solvents.

[0042] Furthermore, the photoresist is a DNQ-phenolic resin type positive photoresist or an epoxy-based negative photoresist; before testing, the photoresist sample is diluted with PGMEA 10-30 times, specifically 10, 15, 16, 17, 18, 19, 20, 21, 22, 25, 28, or 30 times, preferably 15-25 times, and more preferably 18-22 times, to reduce matrix interference.

[0043] In one typical embodiment, the present invention provides a fluorescence detection method for chloride ions, comprising the following steps: The sample to be tested was reacted with the above fluorescent probes B2 and Ag. + Mix and incubate; The fluorescence intensity of the system at 550 nm was measured at an excitation wavelength of 420 nm. According to Cl - The standard curve of concentration versus fluorescence recovery intensity was used to calculate the Cl concentration in the sample. - The concentration.

[0044] Furthermore, the incubation time is 20-50 minutes, preferably 20-40 minutes, and most preferably 30 minutes.

[0045] Furthermore, the detection is carried out in an organic solvent medium, wherein the organic solvent is selected from at least one of propylene glycol methyl ether acetate (PGMEA), dimethyl sulfoxide (DMSO), ethyl lactate (EL), tetrahydrofuran (THF), or acetone, preferably PGMEA.

[0046] Furthermore, the Cl -The linear range of the standard curve for concentration versus fluorescence recovery intensity is 0–80 μM, with a detection limit of less than 0.1 ppm, preferably ≤0.05 ppm, specifically 0.0411 ppm. Detection time is <10 min.

[0047] In one typical embodiment, the present invention provides a rapid detection method for chloride ions in photoresist, comprising: The photoresist sample was diluted with an organic solvent; the fluorescent probe and Ag were added. + Forming probe-Ag + Complexes were analyzed, and fluorescence recovery intensity was measured.

[0048] Preferably, the organic solvent is selected from at least one of propylene glycol methyl ether acetate (PGMEA), dimethyl sulfoxide (DMSO), ethyl lactate (EL), tetrahydrofuran (THF), or acetone, with PGMEA being the most preferred.

[0049] Preferably, the dilution is 10 to 30 times, more preferably 18 to 22 times, and most preferably 20 times.

[0050] Obvious Cl can be observed in the photoresist - The concentration-dependent fluorescence recovery response successfully enabled rapid and direct quantitative detection of chloride ions in the original liquid photoresist sample before spin coating.

[0051] In this invention, unless otherwise specified, all other test materials and instruments are conventional test materials in the field and can be purchased through commercial channels.

[0052] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0053] Example 1: Synthesis of compound A1 20.816 g (20 mmol) of sodium bisulfite was weighed and dissolved in 80.00 mL of water. In a 250 mL round-bottom flask, 1.121 g (10 mmol) of 2-thiophenecarboxaldehyde and 1.531 g (10 mmol) of 4-nitro-o-phenylenediamine were added sequentially. The inner wall of the reaction flask was rinsed with a small amount of distilled water, and the system was heated under reflux in distilled water for 5 h. The reaction progress was closely monitored by TLC during this period. After the reaction was complete, the reaction mixture was cooled to room temperature, and a small amount of ice water was added. The precipitate was separated by vacuum filtration. The obtained solid was purified by silica gel column chromatography using dichloromethane and methanol (50:1 v / v) as eluents. Compound A1 was successfully obtained, with a yield of 1.98 g, representing a yield of 80.5%.

[0054] 1H NMR (400 MHz, CDCl3) δ 12.88 (s, 1H), 8.47 (s, 1H), 8.18 (dd, J =9.1, 2.2 Hz, 1H), 7.90 (d, J = 3.7 Hz, 1H), 7.63 (t, J = 7.0 Hz, 1H), 7.50(d, J = 5.0 Hz, 1H), 7.13 (dd, J = 5.0, 3.8 Hz, 1H). 13 C NMR (101 MHz, DMSO-d6)δ 151.00, 142.54, 139.49, 132.38, 130.20, 128.41, 117.93, 114.35, 111.15,107.44.HRMS (ESI) calculated for C 11 H7N3O2S [MH] - : 244.0181, found 244.0191. Example 2: Synthesis of compound A2 In a 250 mL round-bottom flask, A1 and 4,4'-bipyridine (0.312 g, 2 mmol) were dissolved in 20 mL of DMF, and B2(OH)4 (4.35 g, 48.5 mmol) was slowly added in portions. The reaction mixture was stirred at room temperature for 10 min. During this time, the reaction progress was closely monitored by TLC. After the reaction was complete, the reaction mixture was extracted with ethyl acetate, the solvent was evaporated under reduced pressure, and the crude product was subjected to silica gel column chromatography using dichloromethane and methanol (32:1 v / v) as eluents. Compound A2 was successfully obtained in a yield of 1.46 g, representing a yield of 84.9%.

[0055] 1 H NMR (400 MHz, DMSO-d6) δ 12.35 (s, 1H), 7.80 – 7.53 (m, 2H), 7.36 –7.07 (m, 2H), 6.78 – 6.41 (m, 2H), 4.97 (s, 2H). 13 C NMR (101 MHz, DMSO-d6) δ145.09, 134.53, 128.05, 127.31, 125.13, 111.75.HRMS (ESI) calculated forC 11 H9N3S [M+H] - : 216.0595, found 216.0573. Example 3: Synthesis of compound A3 In a 100 mL round-bottom flask, 1.874 g (6.7 mmol) of 4-bromo-1,8-naphthoic anhydride was dissolved in 15 mL of anhydrous ethanol, and then A2 was slowly added. The system was heated under reflux for 36 h, and the reaction progress was monitored in real time using thin-layer chromatography (TLC). After the reaction was complete, the reaction mixture was cooled to room temperature, and excess ethanol was removed by rotary evaporation. Subsequently, the reaction mixture was extracted with ethyl acetate, and excess solvent was removed by rotary evaporation. Then, purification was performed using column chromatography, with petroleum ether and ethyl acetate (1:1 v / v) as the eluent. Compound A3 was successfully obtained, with a yield of 2.23 g, representing a yield of 68.1%.

[0056] 1 H NMR (400 MHz, CDCl3) δ 8.53 (d, J = 7.2 Hz, 1H), 8.43 (d, J = 8.5Hz, 1H), 8.28 (d, J = 7.8 Hz, 1H), 7.90 (d, J = 7.8 Hz, 1H), 7.71 (t, J = 7.9Hz, 1H), 7.51 – 7.12 (m, 4H), 6.85 (q, J = 6.9 Hz, 2H). 13 C NMR (101 MHz, CDCl3) δ 171.33, 164.59, 148.99, 133.83, 132.99, 132.68, 131.80, 131.31,130.98, 130.69, 130.01, 129.37, 129.26, 128.44, 128.29, 127.96, 127.31,123.07, 122.19.HRMS (ESI) calculated for C 22 H 11 BrN3O2S [M+H] - : 473.9912, found473.9882. Example 4: Synthesis of Intermediate B1 In a 250 mL round-bottom flask, thiophene-2,5-dicarboxaldehyde (0.701 g, 5 mmol) and 4-nitro-o-phenylenediamine (1.531 g, 10 mmol) were added sequentially in 20 mL of dimethyl sulfoxide. The mixture was heated to 130 °C and reacted for 6 h. After cooling to room temperature, 5 mL of cold ethanol was added, and the mixture was stirred for 10 min to precipitate the precipitate. The precipitate was then filtered under vacuum, washed with ethanol (10 mL × 3), and dried. The precipitate was purified by column chromatography (dichloromethane:methanol = 20:1) to give 1.84 g of B1, with a yield of 80.7%.

[0057] 1 H NMR (400 MHz, DMSO-d6): δ 13.83 (s, 2H), 8.45 (s, 2H), 8.12 (dd, J=8.9,2.2 Hz, 2H), 8.00 (s, 2H), 7.75 (d, J=8.9 Hz, 2H). 13 C NMR (101 MHz, DMSO-d6): δ 143.31, 136.85, 133.93, 115.56, 111.44, 108.08. HRMS (ESI) m / z: [M+H] + Calculated value C 18 H 11 N6O4S: 407.0562, measured value 407.0532.

[0058] Example 5: Synthesis of target probe B2 In a 250 mL round-bottom flask, B1 (0.159 g, 2.3 mmol) and 4,4′-bipyridine (0.159 g, 2.3 mmol) were dissolved in 10 mL of DMF. B2(OH)4 (2.44 g, 27.2 mmol) was added in portions, and the mixture was stirred at room temperature for 10 min. After the reaction was complete, the mixture was extracted with ethyl acetate, the organic layer was washed with water, and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure, and the mixture was purified by column chromatography (dichloromethane:methanol = 15:1) to give 1.16 g of B2, with a yield of 73.9%.

[0059] 1 H NMR (400 MHz, DMSO-d6): δ 7.74 (s, 2H), 7.28 (d, J=8.5 Hz, 1H), 6.81-6.46 (m, 3H), 3.64-3.21 (m, 7H). 13C NMR (101 MHz, DMSO-d6): δ 134.83, 129.68, 125.96, 112.20. HRMS (ESI) m / z: [M+H] + Calculated value C 18 H 15 N6S: 347.1079, measured value 347.1052.

[0060] Example 6: B2 probe against Ag + and Cl - fluorescence response test Take 20 μL of B2 probe standard solution (2.00 mM) into a centrifuge tube, add PGMEA solution to make up to 2.00 mL (final B2 concentration 20.0 μM), and measure (λ) on a fluorescence spectrophotometer. ex =420 nm, λ em =550 nm).

[0061] Different concentrations of Ag were added to the B2 probe solution. + Standard solutions (0, 5, 10, 15, 20, 25, 30, 35, 40 μM) were incubated for 30 min, and then fluorescence spectra were measured. The results showed that with the increase of Ag... + As the concentration increases, the fluorescence intensity at 550 nm gradually decreases, Ag + Fluorescence quenching efficiency >80% at 40 μM.

[0062] To B2-Ag + Complex (B2 20.0 μM, Ag) + Different concentrations of Cl were added to 40.0 μM. - Standard solutions (0, 10, 20, 30, 40, 50, 60, 70, 80 μM) were incubated for 30 min, and then fluorescence spectra were measured. The results showed that Cl... - The fluorescence recovery intensity at 550 nm is related to the concentration in the range of 0–80 μM. - The concentration showed a good linear relationship, R 2 =0.9929, and the detection limit (3σ / k) is 0.0411 ppm.

[0063] Example 7: Quantitative detection of chloride ions in photoresist using the B2 probe Commercial SPR955-CM positive photoresist and SU-8 2000.5 negative photoresist were diluted 20 times with PGMEA to serve as test media.

[0064] Add B2-Ag to the diluted photoresist sample +Complex (B2 final concentration 20.0 μM, Ag) + Final concentration 40.0 μM), then add different concentrations of Cl - Fluorescence spectra were measured after incubation of standard solutions (0, 20, 40, 60, 80, 100 μM) for 30 min.

[0065] The results showed that in the SPR955-CM photoresist, the fluorescence emission peak was located at 515 nm; in SU-8 2000.5, the fluorescence emission peak was located at 531 nm (a blue shift compared to 550 nm in pure PGMEA, possibly attributed to the photoresist's own color filtering effect). Significant Cl- concentrations were observed in both photoresists. - The concentration-dependent fluorescence recovery response successfully enabled rapid and direct quantitative detection of chloride ions in the original liquid photoresist sample before spin coating.

[0066] Comparative Example 1: Comparison of monobenzimidazole probe A2 The synthesized A2 probe (monobenzimidazole structure) was tested according to the method in Example 6. The results showed that the A2 probe was effective against Ag... + The fluorescence quenching efficiency of B2 is significantly lower than that of Cl. - The detection limit was 0.109 ppm, approximately 2.6 times that of B2. This indicates that the chelating effect of the bisbenzimidazole structure significantly enhances the stability of the complex and improves the detection sensitivity.

[0067] Additionally, it should be noted that the probes A1 and A3 have no fluorescence effect and are only used for molecular structure comparison.

[0068] Comparative Example 2: No Ag + Mediated direct Cl - Detection The B2 probe (20.0 μM) was directly reacted with Cl - Mix at (80.0 μM) without adding Ag. + After incubation for 30 min, the fluorescence spectrum was measured. The results showed that the fluorescence intensity of the B2 probe was similar to that without Cl. - The timing was basically the same, with no recovery response. This indicates that the B2 probe cannot directly identify Cl. - It must be done through Ag + Mediated, consistent with ligand replacement mechanism.

[0069] Depend on Figure 3 It can be seen that: with Ag + With increasing concentration, the fluorescence intensity of the B2 probe at 550 nm gradually decreased. When Ag... + At a concentration of 40.0 μM, the fluorescence quenching efficiency exceeded 80%. (In B2-Ag) +Complex system (B2 = 20.0 μM, Ag) + Add Cl to (40.0 μM) - The standard solutions (0 ~ 80.0 μM) showed a regular increase in fluorescence intensity, and the two exhibited a good linear relationship (R0). 2 = 0.9929), and based on 3σ / k (σ = 10.20), the B2 probe's response to Cl is calculated. - The detection limit is 1.16 µM, which translates to 0.0411 ppm < 0.1 ppm.

[0070] Depend on Figure 4 It can be seen that adding Ag to the B2 probe solution (20.0 μM) + After adding 40.0 μM, the fluorescence intensity at 550 nm decreased rapidly over time. Within the first 20 s, the fluorescence intensity dropped sharply, exhibiting a rapid quenching response. Subsequently, the quenching rate gradually slowed, and the fluorescence intensity essentially stabilized at approximately 50 s. (The text then abruptly shifts to a seemingly unrelated topic about B2-Ag.) + Adding Cl to the complex - After (80.0 μM), the fluorescence intensity gradually recovered over time, and the fluorescence intensity basically stabilized at about 6 min.

[0071] Depend on Figure 5 It can be seen that: when the two photoresist samples are diluted with PGMEA solvent and used as the test medium, in B2-Ag... + Complex (B2 = 20.0 μM, Ag) + Different concentrations of Cl were added to (40.0 μM) - Standard solutions (0 ~ 100 μM) were used to record the fluorescence spectral changes of each system.

[0072] Dilution factor: In the initial stages of the experiment, the photoresist samples were diluted 10 times and 15 times before measurement. The results showed that even with the addition of high concentrations of Cl... - (100 μM), B2-Ag + The fluorescence signal of the complex also showed no significant change. When the dilution factor was increased to 20-fold, the matrix interference effect was significantly weakened, and Cl... - For B2-Ag + The fluorescence of the complex began to recover. In the SPR 955-CM photoresist system, B2-Ag +The fluorescence emission peaks of the complexes were all located at 515 nm; in the SU-8 2000.5 photoresist system, the emission peak was located at 531 nm, showing a significant blue shift compared to the 550 nm fluorescence emission peak in the pure PGMEA medium. This phenomenon may be attributed to the fact that the photoresist itself is red, retaining some color even after 20-fold dilution, which produces a certain internal filtering effect or spectral shift on the fluorescence emission of the probe.

[0073] Specific detection: To investigate the effect of the B2 probe on Ag + and Cl - The specific recognition ability of the B2 probe (20.0 μM) was determined in PGMEA medium, and the fluorescence response of the B2 probe to various metal ions and the B2-Ag were measured. + Complex (B2 = 20.0 μM, Ag) + The fluorescence response of a multi-ion at 40.0 μM (e.g., 40.0 μM) is shown in the following results. Figure 6 As shown. Various metal ions were added to the B2 probe solution, and the fluorescence intensity of each system at 550 nm was recorded.

[0074] Experimental results show that only when Ag is added + At that time, the fluorescence intensity of the B2 probe was significantly quenched. However, after the addition of other metal ions, the fluorescence intensity of the B2 probe did not change significantly and remained basically consistent with the blank control. Similarly, when B2-Ag was added... + Various ions were added to the complex system, and the fluorescence intensity of each system at 550 nm was recorded. Experimental results show that only when Cl is added... - At that time, B2-Ag + The fluorescence intensity of the complex recovered significantly. In summary, the B2 probe is effective against Ag. + and Cl - It exhibits excellent selective recognition capabilities.

[0075] Selectivity of probe B2 in different solvents: To investigate the effects of different solvents on the recognition of Ag by the B2 probe + and Cl - The effect of Ag on the B2 probe was determined in seven different solvents. + Fluorescence quenching spectrum at (40.0 μM) and the addition of Cl - The fluorescence recovery spectrum after (80.0 μM) is shown in the following results. Figure 7 As shown. In organic solvents such as PGMEA, DMSO, EL, THF, and acetone, Ag... +It can effectively bind to the nitrogen and sulfur coordinating atoms in the B2 probe, forming stable complexes and thus quenching the probe fluorescence. In acetone and THF, the quenching efficiency is comparable to that of PGMEA. In methanol, the quenching efficiency is slightly reduced. However, in aqueous systems, the hydrogen bonding between water molecules and the probe may interfere with the interaction between the probe and Ag. + Coordination of Ag, and Ag + The solvation effect in water is strong, leading to the B2 probe's resistance to Ag. + The fluorescence quenching response was significantly weakened.

[0076] B2-Ag in each solvent system + Adding Cl to the complex - After reaching 80.0 μM, the fluorescence recovery also showed solvent dependence. In organic solvents such as PGMEA, DMSO, EL, THF, and acetone, Cl... - Able to effectively compete and combine Ag + The fluorescence of the B2 probe was restored. The fluorescence recovery efficiency in acetone and THF was similar to that in PGMEA. Considering that PGMEA is the practical solvent for photoresist applications, and that the B2 probe exhibits excellent response performance in this solvent, PGMEA was selected as the test medium for subsequent experiments.

[0077] probe against Ag + and Cl - pH stability before and after the response: To determine the effect of pH on Cl - The effect of detection was investigated in the pH range of 4.0 to 9.0 on B2-Ag. + Complexes on Cl - Changes in fluorescence response, such as Figure 8 As shown. With changes in pH conditions, B2-Ag... + Complexes on Cl - They exhibited different sensitivities. Among them, B2-Ag + Fluorescence quenching state of the complex and its effect on Cl - The fluorescence recovery response is most ideal under neutral and weakly alkaline conditions at pH 6.0 to 8.0, and these trends may be due to the pH-sensitive benzimidazole group.

[0078] probe against Ag + and Cl - Response time: To investigate the effect of the B2 probe on Ag + and Cl - The response speed and time stability of the B2 probe were monitored in PGMEA medium, specifically during the fluorescence quenching process of the B2 probe and the addition of Cl. -The fluorescence recovery process was then recorded, and the changes in fluorescence intensity over time were observed. The results are as follows: Figure 9 As shown. Ag was added to the B2 probe solution (20.0 μM). + After adding 40.0 μM, the fluorescence intensity at 550 nm decreased rapidly over time. Within the first 20 s, the fluorescence intensity dropped sharply, exhibiting a rapid quenching response. Subsequently, the quenching rate gradually slowed, and the fluorescence intensity essentially stabilized at approximately 50 s. (The text then abruptly shifts to a seemingly unrelated topic about B2-Ag.) + Adding Cl to the complex - After being distilled at 80.0 μM, the fluorescence intensity gradually recovered over time. The recovery rate was rapid in the first 3 minutes, but gradually slowed down over time, reaching a stable level around 6 minutes.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fluorescent probe for the detection of trace chloride ions, characterized in that, The fluorescent probe is bis(benzimidazol-2-yl)thiophene-2,5-diamine, denoted as B2, and its structural formula is shown below: 。 2. The fluorescent probe according to claim 1, characterized in that, B2 has an excitation wavelength of 420 nm and an emission wavelength of 550 nm. Preferably, the fluorescent probe achieves indirect fluorescence detection of chloride ions through silver ion mediation, and the detection mechanism is as follows: the B2 probe reacts with Ag... + The formation of a 1:1 complex leads to fluorescence quenching, Cl - With Ag + Competitive complexation occurs, causing the fluorescence of the B2 probe to recover.

3. A method for preparing a fluorescent probe for trace chloride ion detection as described in claim 1 or 2, characterized in that, Includes the following steps: Thiophene-2,5-dicarboxaldehyde was reacted with 4-nitro-o-phenylenediamine in an organic solvent by heating to obtain intermediate B1; Intermediate B1 was reacted with 4,4′-bipyridine and B2(OH)4 at room temperature to reduce the nitro group to an amino group, yielding the target product B2.

4. The preparation method according to claim 3, characterized in that, In the preparation of intermediate B1, the molar ratio of thiophene-2,5-dicarboxaldehyde to 4-nitro-o-phenylenediamine is (2~10):(5~15); Preferably, the organic solvent includes dimethyl sulfoxide; Preferably, the heating reaction conditions are: reaction at 120~150℃ for 4~10 h.

5. The preparation method according to claim 3, characterized in that, In the preparation of the target product B2, the molar ratio of intermediate B1, 4,4′-bipyridine and B2(OH)4 is (1~5):(1~5):(20~30); Preferably, stir at room temperature for 5 to 30 minutes.

6. The application of a fluorescent probe for trace chloride ion detection as described in claim 1 or 2, or a fluorescent probe for trace chloride ion detection prepared by the preparation method described in any one of claims 3 to 5, in the detection of trace chloride ions.

7. The application according to claim 6, characterized in that, Applications in the detection of trace chloride ions in photoresists, electronic chemicals, and high-purity solvents; Preferably, the photoresist includes DNQ-phenolic resin type positive photoresist or epoxy type negative photoresist.

8. A fluorescence detection method for chloride ions in solution, characterized in that, Includes the following steps: The sample to be tested is combined with the fluorescent probe and Ag as described in claim 1 or 2. + Mix and incubate; The fluorescence intensity of the system at 550 nm was measured at an excitation wavelength of 420 nm. According to Cl - The standard curve of concentration versus fluorescence recovery intensity was used to calculate the Cl concentration in the sample. - The concentration.

9. The fluorescence detection method according to claim 8, characterized in that, Incubate for 20-50 minutes; Preferably, the detection is performed in an organic solvent medium, wherein the organic solvent is selected from at least one of propylene glycol methyl ether acetate, dimethyl sulfoxide, ethyl lactate, tetrahydrofuran, or acetone; Preferably, the Cl - The linear range of the standard curve for concentration versus fluorescence recovery intensity is 0–80 μM, and the detection time is <10 min.

10. A rapid detection method for chloride ions in photoresist, characterized in that, include: Dilute the photoresist sample with an organic solvent; Add the fluorescent probe of claim 1 or 2 with Ag + Forming probe-Ag + Complexes were analyzed, and fluorescence recovery intensity was measured.

Images