CN113461956B - Ruthenium polymer, preparation method thereof and pH value detection fluorescent probe - Google Patents

Abstract

The invention relates to the technical field of complexes, and particularly relates to a ruthenium polymer, a preparation method thereof and a pH value detection fluorescent probe. The invention discloses a ruthenium polymer with a chemical formula shown in a formula (I), which has the advantages of novel structure, better luminescence characteristic, excellent optical property, long excited state service life, sensitivity to pH response, wide response range and wide linear range, and is particularly obvious between pH =4 and pH = 8. The ruthenium polymer can sensitively detect the change of pH level in a living body by utilizing a fluorescence technology, can be used as a novel fluorescent high-molecular probe, and is applied to the field of fluorescence biological imaging in life science research.

Description

A kind of ruthenium polymer and its preparation method and pH value detection fluorescent probe

technical field

The invention relates to the technical field of complexes, in particular to a ruthenium polymer, a preparation method thereof and a fluorescent probe for pH value detection.

Background technique

The pH value plays a vital role in fields such as production process, environmental monitoring and medical etiology screening. For example, many diseases such as type 2 diabetes, Alzheimer's disease, cancer, etc. can cause small fluctuations in pH in the body. Therefore, it is necessary to develop sensors that can quickly and accurately detect pH and monitor its changes. Compared with traditional pH detection methods such as pH test paper method, NMR method and electrochemical method, fluorescence detection method has the advantages of simple operation, rapid response, high sensitivity, and continuous dynamic monitoring. It is one of the ideal materials for this type of sensor. . However, the pH fluorescent sensors reported so far, especially the pH-MOF sensors, have disadvantages such as poor stability, small pH response range, unclear linear relationship, and inability to be recycled. In practical applications, sometimes multiple detection methods need to be coordinated to achieve Effective monitoring of target sample pH.

Contents of the invention

In view of this, the present invention provides a ruthenium polymer and its preparation method and pH value detection fluorescent probe, the ruthenium polymer has good luminescence characteristics, excellent optical properties, long excited state lifetime, sensitive to pH response, Wide response range and wide linear range.

Its specific technical scheme is as follows:

The invention provides a ruthenium polymer, which has the chemical formula shown in formula (I) and the structure shown in formula (II);

{Ru[(N^N)(bipb)} _n X _2n formula (Ⅰ);

均为1,10-邻菲罗啉或联吡啶，X为无机盐阴离子，n＝2～20，优选为2、9、10、11、12、13，更优选为10。Among them, (N^N) in formula (I) and in formula (II)

Both are 1,10-phenanthroline or bipyridine, X is an anion of inorganic salt, n=2-20, preferably 2, 9, 10, 11, 12, 13, more preferably 10.

When (N^N) is 1,10-phenanthroline, the structural formula of the ruthenium polymer is as follows:

When (N^N) is bipyridine, the structural formula of the ruthenium polymer is as follows:

The ruthenium polymer provided by the present invention has a novel structure, and the ruthenium polymer has good luminescent characteristics, excellent optical properties, long excited state lifetime, simple synthesis steps, sensitive to pH response, wide response range and wide linear range, and can be used as a A novel fluorescent probe for pH detection.

In the present invention, the inorganic salt anion is water-soluble, and the inorganic salt anion is selected from ClO ₄ ^- , NO ₃ ^- , PF ₆ ^- or Br ^- ;

The present invention also provides a kind of preparation method of ruthenium polymer, comprises the following steps:

The organic complex of bipb and ruthenium is mixed in the reaction solvent, carry out reflux reaction, then add inorganic salt, obtain the ruthenium polymer of chemical formula shown in formula (I) and the structure shown in formula (II);

{Ru[(N^N)(bipb)]} _n X _2n formula (Ⅰ);

为1,10-邻菲罗啉或联吡啶，X为无机盐阴离子，n＝2～20。Among them, (N^N) in formula (I) and in formula (II)

It is 1,10-phenanthroline or bipyridine, X is an anion of inorganic salt, n=2-20.

The synthesis route of the ruthenium polymer provided by the invention is simple and safe, and the synthesis raw materials are cheap and easy to obtain.

In the present invention, bipb (1,4-bis(1L2-imidazo[4,5-f][1,10]phenanthroline-2-yl)benzene) has the following structure:

The preparation method of described bipb comprises the following steps:

1,10-phenanthroline-5,6-dione, ammonium acetate and terephthalaldehyde are refluxed in a solvent to obtain bipb; the solvent is selected from glacial acetic acid, propionic acid, ethanol or methanol; the The molar ratio of 1,10-phenanthroline-5,6-dione, ammonium acetate and terephthalaldehyde is 1:20:0.5; the temperature of the reflux reaction is 118°C, and the reaction time is 3h～ 6h, preferably 3h.

In the present invention, the organic complex of ruthenium is selected from Ru(phen)Cl ₄ or Ru(bpy)Cl ₄ , preferably Ru(phen)Cl ₄ .

In the present invention, the organic complexes of bipb and ruthenium are mixed in a reaction solvent, and then reflux reaction is carried out; the reaction solvent is selected from ethanol, ethylene glycol or N,N-dimethylformamide, preferably N,N -dimethylformamide; the reflux reaction is preferably carried out in the presence of nitrogen or an inert gas; the temperature of the reflux reaction is 140°C, and the time is 6 to 8h, preferably 6h; the bipb and the ruthenium The molar ratio of the organic complex is (1-3):1, preferably 1:1.

In the present invention, after the reflux reaction is completed, an inorganic salt is added to obtain the ruthenium polymer; the inorganic salt is selected from sodium perchlorate or ammonium hexafluorophosphate.

The present invention also provides a ruthenium polymer, which has the chemical formula shown in formula (I) and the hydrate of the structure shown in formula (II).

The present invention also provides the compound shown in formula (I) and formula (II), or the ruthenium polymer obtained by the above preparation method, or the hydrate of the compound shown in formula (I) and formula (II) in pH value detection fluorescence Probe application.

The present invention also provides a fluorescent probe for pH value detection, including the compound shown in formula (I) and formula (II), or the ruthenium polymer prepared by the above preparation method, or the compound shown in formula (I) and formula (II) hydrated ruthenium polymers.

The concentration titration of the two ruthenium polymers provided by the present invention is carried out in acetonitrile, and the fluorescence of the corresponding concentration is measured. It can be found that under a certain concentration, the fluorescence intensity is negatively correlated with the compound concentration.

The present invention also provides a method for fluorescence detection of pH, wherein any one of the ruthenium polymers mentioned above is subjected to pH titration in a buffer solution, and the fluorescence of the corresponding pH is measured, and the pH can be sensitively detected by the change of the fluorescence intensity.

The present invention also provides a method for detecting pH by fluorescence lifetime. The pH titration of any one of the above ruthenium polymers in a buffer solution is carried out, and the fluorescence lifetime of the corresponding pH is measured, and the pH can be sensitively detected by the change of the fluorescence lifetime.

As can be seen from the above technical solutions, the present invention has the following advantages:

The present invention provides a ruthenium polymer having the chemical formula shown in formula (I), the ruthenium polymer has a novel structure, good luminescence characteristics, excellent optical properties, long excited state lifetime, sensitive to pH response, and wide response range , The linear range is wide, and it is especially obvious between pH=4~8. The ruthenium polymer can sensitively detect the change of pH level in organisms by using fluorescence technology, and can be used as a new type of fluorescent polymer probe in the field of fluorescent bioimaging in life science research.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative efforts.

Fig. 1 is the {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n mass spectrum obtained in Example 4 of the present invention;

Fig. 2 is the particle size distribution diagram of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n prepared in Example 4 of the present invention;

Fig. 3 is the particle size distribution diagram of [Ru ₂ (phen) ₄ (bipb)] (ClO ₄ ) ₄ provided by the present invention;

Fig. 4 is a concentration fluorescence titration result graph of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n in acetonitrile under excitation at 375nm prepared in Example 4 of the present invention;

Fig. 5 is a concentration fluorescence titration result diagram of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n in acetonitrile under 450 nm excitation prepared in Example 4 of the present invention;

Fig. 6 is a fluorescence titration result diagram of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n prepared in Example 4 of the present invention in a pH response experiment in a buffer under excitation at 450 nm;

Fig. 7 is a fluorescence titration result diagram of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n prepared in Example 4 of the present invention in a pH response experiment in a buffer under excitation at 375 nm;

Fig. 8 is a diagram of fluorescence lifetime measurement results of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n prepared in Example 4 of the present invention at pH=4 and pH=8 in a buffer under excitation at 316 nm;

Fig. 9 is a graph showing the measurement results of fluorescence lifetimes of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n prepared in Example 4 of the present invention under excitation at 450 nm in buffer solution at pH=4 and pH=8.

detailed description

In order to make the purpose, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the embodiments described below are only part of the implementation of the present invention example, but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The synthesis of embodiment 1 organic ligand bipb

Add 1,10-phenanthroline-5,6-dione (1.89g, 9mmol), ammonium acetate (13.86g, 180mmol), p-benzaldehyde (0.603g, 4.5mmol) into 150mL glacial acetic acid, The flask was refluxed for 3 hours. After the reaction was completed, it was cooled to room temperature to obtain an orange precipitate, which was collected by filtration and washed with water and ethanol three times. Put it into a vacuum oven and dry at 40° C. for 12 hours to obtain an orange-yellow solid with a yield of 1.327 g and a yield of 57.4%.

_The preparation of the organic complex Ru(phen)Cl of embodiment 2 ruthenium

Ruthenium trichloride hydrate (1g, 3.8mmol), 1,10-phenanthroline (0.9g, 4.5mmol) were added in the hydrochloric acid of 100mL1N, under the condition of nitrogen protection, stir 30min in dark place, reaction temperature is room temperature, Overnight, the precipitate was collected, fully washed with water three times, and dried under vacuum at 40° C. for 12 hours to obtain a black powder solid with a yield of 1.692 g and a yield of 80%.

The preparation of the organic complex Ru(bpy)Cl of embodiment ₃ ruthenium

Ruthenium trichloride hydrate (1g, 3.8mmol), bipyridine (0.22g, 3.8mmol) was added to 5mL of 1N hydrochloric acid, mixed and stirred for 30 minutes, placed in a stoppered flask for 3 weeks, filtered, water and ether After washing and drying, a brown powder solid was obtained, yield 1.4 g, yield: 92.1%.

Synthesis of Example 4 Polymer {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n

The bipb (0.514g, 1mmol) prepared in Example 1 and Ru(phen)Cl ₄ (0.423g, 1mmol) were added to a round bottom flask, 25mL of N,N-dimethylformamide was added, and the mixture was protected under nitrogen Reflux for 6 hours to obtain a clear solution, dilute with water, add saturated sodium perchlorate solution to obtain a black solid, filter with suction, and wash the precipitate with water three times. Dry in vacuum for 12 hours to obtain a black solid with a yield of 0.498g and a yield of 47.5%.

As shown in Fig. 1, the peak position of 525.10 in the spectrum is the polymer component when n=2.

As shown in Figure 2, the particle size of the polymer {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n is mainly distributed in two ranges: 116.3nm-174.9nm, 594.6-894.1nm, among which the particle size of 700nm The highest abundance is the main component. In order to analyze the degree of polymerization, we also measured the particle size of the dinuclear complex [Ru ₂ (phen) ₄ (bipb)](ClO ₄ ) ₄ (Figure 3) for comparison. As shown in Fig. 3, the particle size distribution range of [Ru ₂ (phen) ₄ (bipb)](ClO ₄ ) ₄ is 123.1-142.7 nm, and the average particle size is 133 nm. The composition of 116.3nm-174.9nm in the polymer is basically consistent with the particle size of [Ru ₂ (phen) ₄ (bipb)](ClO ₄ ) ₄ , indicating that there is a dinuclear polymer with n value of 2. 594.6-894.1nm is about 4.5-6.5 times the average particle size of the dinuclear complex, indicating that there are polymers with an n value of 9-13, among which the particle abundance of 700nm is the highest, and it is a polymer with n=10, which is its main component . As shown in Figure 2 and Figure 3, the values of n in {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n are 2, 9, 10, 11, 12, 13, and n=10 is the main component.

Synthesis of Example 5 polymer {Ru[(bpy)(bipb)]} _n (ClO ₄ ) _2n

Add bipb (0.514g, 1mmol) and Ru(bpy)Cl ₄ (0.400g, 1mmol) prepared in Example 1 into a round bottom flask, add 25mL N,N-dimethylformamide, and place the mixture under nitrogen protection Reflux for 6 hours to obtain a clear solution, dilute with water, add saturated sodium perchlorate solution to obtain a black solid, filter with suction, and wash the precipitate with water three times. Dry it in vacuum for 12 hours to obtain a black solid with a yield of 0.563 g and a yield of 55.35%.

Example 6 Aggregation-induced quenching of polymer {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n

Prepare an acetonitrile solution of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n with a concentration of 10 μmol/L, measure its absorbance with a UV-visible spectrophotometer and draw the absorption spectrum curve to obtain the characteristic absorption of the polymer Peak wavelength, using the wavelength as the excitation wavelength, and then using a fluorescence spectrometer to test its fluorescence intensity, the polymer is a double fluorescence emission and has a strong fluorescence intensity.

As shown in Figure 4 and Figure 5, an acetonitrile solution of {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n with a certain concentration gradient was prepared, and the fluorescence intensity was measured, and it was observed that there was an obvious phenomenon of aggregation-induced quenching , when the concentration is low, the fluorescence is weak due to the small amount of solute, and the fluorescence increases rapidly with the increase of the concentration, reaching the peak at 100 μg/mL, and then with the increase of the concentration, the fluorescence intensity decays rapidly due to aggregation-induced quenching.

Example 7 The pH response of polymer {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n

Prepare 250mL of buffer solution containing 40mM H ₃ BO ₃ , 40mM H ₃ PO ₄ and 40mM CH ₃ COOH, and prepare 1mg/mL {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n in DMSO with buffer solution was diluted 100 times to obtain a 10 μg/mL buffer stock solution.

Take 3 mL of the diluted solution (solution a), measure the pH value, and record; add 3 μL of 5M NaOH dropwise each time, measure the pH value and record it, until the measured pH reaches 11, and the titration ends. Take 3mL of the diluted mother solution (solution a') from the same source as the titration experiment, and similarly, add 5M NaOH dropwise, 3μL each time. The pH value of the solution after each dropwise addition should be the corresponding pH value at the time of titration, and the fluorescence intensity corresponding to the pH value should be measured.

As shown in Figure 6, the fluorescence intensity emitted by {Ru[(phen)(bipb)]} _n (ClO ₄ ) _2n at 600 nm decreases with the increase of pH. And pH = 4 ~ pH = 8 decreased significantly. The pH can thus be detected from the fluorescence intensity. As shown in Figure 7, the polymer is dual-fluorescence emitting, and the fluorescence emission intensity also changes with the change of pH. At 600nm, the intensity of its fluorescence signal decreases with the increase of pH, which is consistent with the results in Figure 3. In the other peak at 428nm, the fluorescence intensity decreases with the increase of pH, and there is an obvious red shift at pH=4, and the fluorescence intensity first increases and then decreases. And as shown in Figure 8 and Figure 9, the fluorescence lifetime of pH=4 and pH=8 has been measured, and it has been observed that there is a certain gap in the fluorescence lifetime of Ex=316nm and Ex=450nm, and the pH can be detected by the fluorescence lifetime . Moreover, when the buffer is used as the solvent, the fluorescence lifetime of the polymer at this pH value conforms to the double-exponential decay curve, wherein the fluorescence lifetimes of Ex=316nm at pH=4 and pH=8 are 2.152ns, 0.337ns, Ex The fluorescence lifetimes of pH=4 and pH=8 at =450 nm are 104.979 ns and 66.329 ns.

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still understand the foregoing The technical solutions recorded in each embodiment are modified, or some of the technical features are replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (9)

1. A ruthenium polymer, characterized in that it has a chemical formula shown in formula (I) or a structure shown in formula (II); {Ru[(N^N)(bipb)]} _n X _2n formula (Ⅰ);

Among them, (N^N) in formula (I) and in formula (II)

It is 1,10-phenanthroline or bipyridine, X is an anion of inorganic salt, n=2-20. 2. The ruthenium polymer according to claim 1, characterized in that the inorganic salt anion is selected from ClO ₄ ⁻ , NO ₃ ⁻ , PF ₆ ⁻ or Br ⁻ . 3. a preparation method of ruthenium polymer, is characterized in that, comprises the following steps: The organic complex of bipb and ruthenium is mixed in the reaction solvent, carries out reflux reaction, then adds inorganic salt, obtains the ruthenium polymer of chemical formula shown in formula (I) or the structure shown in formula (II); {Ru[(N^N)(bipb)]} _n X _2n formula (Ⅰ);

Among them, (N^N) in formula (I) and in formula (II)

It is 1,10-phenanthroline or bipyridine, X is an anion of inorganic salt, n=2-20. 4 . The preparation method according to claim 3 , wherein the organic complex of ruthenium is selected from Ru(phen)Cl ₄ or Ru(bpy)Cl ₄ . 5. preparation method according to claim 3 is characterized in that, the preparation method of described bipb comprises the following steps: 1,10-phenanthroline-5,6-dione, ammonium acetate and terephthalaldehyde were refluxed in a solvent to obtain bipb. 6. The preparation method according to claim 3, wherein the reaction solvent is ethanol, ethylene glycol or N,N-dimethylformamide; The temperature of the reaction is 140° C., and the time is 6-8 hours. 7. The preparation method according to claim 3, characterized in that, the molar ratio of the bipb and the organic complex of ruthenium is (1～3):1. 8. The application of the ruthenium polymer described in claim 1 or 2 or the ruthenium polymer prepared by the preparation method described in any one of claims 3 to 7 in pH value detection fluorescent probes. 9. A fluorescent probe for pH value detection, characterized in that it comprises the ruthenium polymer according to claim 1 or the ruthenium polymer prepared by the preparation method according to any one of claims 3 to 7.

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