阅读说明：本技术 一种以顺式-联噻吩环为构筑单元连接的八元卟啉的合成方法及应用 (Synthesis method and application of octa-porphyrin connected by cis-bithiophene ring as construction unit ) 是由 刘慧茹 薛兆历 于 2019-09-24 设计创作，主要内容包括：本发明属于有机化合物的合成及分离技术领域,公开一种以顺式-联噻为吩构筑单元连接的八元卟啉的合成方法及应用。本发明以二联噻吩为原料,先合成噻吩二醇化合物,再与吡咯反应得到噻吩二吡咯化合物,最后与不同芳香醛反应得到目标产物八元卟啉。该八元卟啉化合物对汞离子具有极高的敏感性和选择性,并且不受其它金属阳离子的影响,可作为高效的汞离子传感器,有较好的应用前景。本发明的优点：提纯方法简单,实验过程容易控制,反应中副产物较少,易于分离提纯。(The invention belongs to the technical field of synthesis and separation of organic compounds, and discloses a synthesis method and application of octatomic porphyrin connected by taking cis-bithiazole as a thiophene construction unit. The method takes bithiophene as a raw material, firstly synthesizes a thiophene diol compound, then reacts with pyrrole to obtain a thiophene dipyrrole compound, and finally reacts with different aromatic aldehydes to obtain a target product, namely octa-porphyrin. The octatomic porphyrin compound has extremely high sensitivity and selectivity to mercury ions, is not influenced by other metal cations, can be used as a high-efficiency mercury ion sensor, and has a good application prospect. The invention has the advantages that: the purification method is simple, the experimental process is easy to control, the by-products in the reaction are less, and the separation and purification are easy.)

1. An octa-porphyrin connected by a cis-bithiophene ring as a construction unit is characterized in that the molecular structural formula is as follows:

wherein Ar is-C₆F₅，-C₆H₄NO₂or-C₆H₄COOCH₃。

2. The method for synthesizing octa-porphyrin connected by cis-bithiophene ring as a building unit according to claim 1, which comprises the following steps:

(1) preparing 5,5 '-diphenylmethyl hydroxyl-2, 2' -bithiophene for later use;

(2) preparing 5,5 '-di (phenyl-2-pyrryl methyl) -2,2' -bithiophene for later use;

(3) and (3) respectively adding the 5,5 '-bis (phenyl-2-pyrrylmethyl) -2,2' -bithiophene prepared in the step (2) and aromatic aldehyde as raw materials into a reactor, adding trifluoroacetic acid into the reactor under the condition of nitrogen protection, taking dichloromethane as a solvent, adding trifluoroacetic acid, stirring the mixture at room temperature in a dark place for 11 to 12 hours, adding 2, 3-dichloro-5, 6-dicyan p-benzoquinone DDQ, removing the nitrogen protection, continuously stirring the mixture for 3 to 4 hours, quenching the mixture by using a saturated sodium bicarbonate solution, extracting, washing with water, drying, removing the solvent under reduced pressure, purifying the compound by using a silica gel column chromatography, and recrystallizing to obtain a crystal of octa porphyrin which is connected by using a cis-bithiophene ring as a construction unit.

3. The method of claim 2, wherein in step (1), the 5,5 '-diphenylmethylhydroxy-2, 2' -bithiophene is prepared by the steps of: taking distilled dry n-hexane as a solvent, dropwise adding n-hexane solution of Tetramethylethylenediamine (TMEDA) and n-butyllithium (n-BuLi) into the reaction solution under the protection of nitrogen, stirring for 10min, dropwise adding 2,2' -bithiophene, refluxing for 1-2 h, cooling to 0 ℃ in an ice water bath, dropwise adding a dry mixed solution of Tetrahydrofuran (THF) and benzaldehyde, after dropwise adding, removing the ice water bath until the temperature is recovered to room temperature, and stirring until the raw materials react completely; adding cold ammonium chloride aqueous solution to carry out quenching reaction, extracting by using dichloromethane, washing by using distilled water and saturated saline solution respectively, drying, then carrying out rotary evaporation to remove the solvent to obtain a crude product, using thin-layer chromatography silica gel as a stationary phase, mixing a mixed solvent of dichloromethane and petroleum ether according to a ratio of 1:1, using the mixture as an eluent to carry out gradient elution, collecting eluted components, and carrying out rotary drying by using a rotary evaporator to obtain a white solid, namely 5,5 '-diphenylmethl-2, 2' -bithiophene.

4. The synthesis method according to claim 3, wherein the n-hexane solution of n-hexane, tetramethylethylenediamine, n-butyllithium (n-BuLi), 2' -bithiophene, tetrahydrofuran and benzaldehyde are used in the following proportions: 52 mL: 4.8 mL: 20mL of: 2.66 g: 20mL of: 3.38g, wherein the concentration of the n-hexane solution of n-butyllithium (n-BuLi) was 1.6 mol/L.

5. The synthesis method of claim 2, wherein in the step (2), the 5,5 '-diphenylmethylhydroxy-2, 2' -bithiophene obtained in the step (1) is added into a reaction flask, 1, 2-dichloroethane is used as a solvent under the protection of nitrogen, pyrrole is added, boron trifluoride diethyl etherate solution is slowly added, the temperature is increased in a gradient manner, and the reflux is carried out for 11-12 h; after the reaction is finished, carrying out suction filtration, removing filter residues, washing reactants by dichloromethane, and removing a solvent by rotary evaporation; carrying out coarse treatment on the product by using a neutral alumina column, taking dichloromethane as eluent, collecting components, and removing the organic solvent by rotary evaporation; then using thin layer chromatography silica gel as a stationary phase, using a mixed solvent of dichloromethane and petroleum ether (volume ratio is 1:3) as an eluent to carry out gradient elution, and removing the solvent under a reduced pressure condition to obtain a yellow oily target product 3, namely 5,5 '-bis (phenyl-2-pyrryl methyl) -2,2' -bithiophene.

6. The method of claim 5, wherein the 5,5 '-diphenylhydroxy-2, 2' -bithiophene, 1, 2-dichloroethane, pyrrole, boron trifluoride etherate are used in an amount of 3 mmol: 40mL of: 10mL of: 1.6 mL.

7. The method of claim 2, wherein in step (3), the 5,5 '-bis (phenyl-2-pyrrylmethyl) -2,2' -bithiophene, the aromatic aldehyde, the trifluoroacetic acid and the DDQ are used in the following ratio: 0.38 mmol: 0.4 mmol: 90 μ L of: 0.86 mmol.

8. The method of claim 2, wherein the aromatic aldehyde is pentafluorobenzaldehyde, p-nitrobenzaldehyde, or methyl p-formylbenzoate.

9. The method of claim 2, wherein in the step (3), dichloromethane is used for extraction, saturated saline is used for washing with water, a rotary evaporator is used for removing the solvent under reduced pressure, gradient elution is performed using a mixed solvent of dichloromethane and petroleum ether as an eluent in the purification of the compound by silica gel column chromatography, and the solvent is removed under reduced pressure by the rotary evaporator.

10. Use of the octaporphyrin of claim 1 linked with cis-bithiophene ring as building block for detecting Hg in solution²⁺The use of (1).

Technical Field

The invention belongs to the technical field of synthesis and separation of organic compounds, and provides a method for synthesizing novel octatomic porphyrin connected by using a cis-bithiophene ring as a construction unit and used for detecting Hg in a solution²⁺The use of ions.

Background

Porphyrin (Porphyrin) is a macrocyclic conjugated heterocyclic compound with aromatic properties, which is widely found in nature. Porphine (Porphine) is used as a heterocyclic parent in a porphyrin molecule, and porphyrins with different structures can be obtained after other substituent groups are connected to the outer ring of the Porphine. Four pyrrole rings in porphyrin are connected through four methine bridges to form a large pi conjugated system with 18 electrons, and the aromatic structure of the porphyrin macrocycle is modified in a targeted manner, so that the porphyrin derivative with special properties can be prepared. Porphyrin molecules have strong modifiability and are mainly divided into three types, namely (1) peripheral modification of porphyrin rings (various functional groups can be introduced at meso-and beta-positions); (2) center modification of porphyrin ring (metal ion is used for replacing hydrogen on porphyrin center nitrogen atom to form metalloporphyrin or porphyrin center nitrogen atom is replaced by heteroatom such as oxygen, sulfur and the like to form heterocyclic porphyrin); (3) changes in porphyrin parent ring (changing the number of pyrrole rings gives both compressed and expanded porphyrins). The modified porphyrin not only retains the structure and the characteristics of partial porphyrin, but also has unique properties, and becomes a molecule with special function selectivity and is applied to the fields of medicine, bionics, material chemistry, analytical chemistry and the like. Wherein, compared with the common porphyrin, the properties of the expanded porphyrin formed by increasing the number of pyrrole rings are obviously changed. The ring formed by the expanded porphyrin along with the increase of pyrrole rings is correspondingly enlarged, so that a plurality of annular space structures can exist, and the flexibility of the annular structure is enhanced. Research shows that with the increase of pyrrole rings, the ultraviolet-absorption visible spectrum of the expanded porphyrin generates obvious red shift. The expanded porphyrin has the advantages of higher molar absorption coefficient, stable optical property, extremely strong structure modifiability, obvious spectral shift and the like, and becomes a research hotspot in the scientific fields of chemistry, materials, biology and the like.

Disclosure of Invention

The invention aims to provide a novel synthetic method of an octatomic porphyrin compound taking a cis-bithiophene unit as an intermediate link and property representation thereof. Bithiophene is taken as a raw material, a bithiophene diol compound is firstly synthesized, then the bithiophene diol compound reacts with pyrrole to obtain a bithiophene dipyrrole compound, and finally the bithiophene dipyrrole compound reacts with different aromatic aldehydes to obtain a target product, namely an octatomic porphyrin compound. The octaporphyrin has twisted 8-shaped structure and is used for treating Hg²⁺The ions have extremely high sensitivity and selectivity. When the target product encounters Hg in solution²⁺Upon ionization, the uv absorption spectrum undergoes a significant red shift and the solution changes color from red to blue. At the same time other metalsCation pair Hg²⁺The detection of ions has no obvious interference, so the novel octatomic porphyrin compound can be used as a sensor to be applied to Hg in solution²⁺And (4) qualitatively detecting the ions.

The octa-porphyrin connected by taking a cis-bithiophene ring as a construction unit has the following molecular structural formula:

the compounds have the formula 4a: C₇₄H₃₈F₁₀N₄S₄、4b:C₇₄H₄₆O₄N₆S₄、4c:C₇₈H₅₂O₄N₄S₄The synthetic route involved in the invention is as follows:

the invention relates to a method for synthesizing octatomic porphyrin by connecting cis-bithiophene rings serving as construction units, which comprises the following steps:

(1) taking distilled dry n-hexane as a solvent, dropwise adding n-hexane solution of Tetramethylethylenediamine (TMEDA) and n-butyllithium (n-BuLi) into the reaction solution under the protection of nitrogen, stirring for 10min, dropwise adding 2,2' -bithiophene, refluxing for 1-2 h, cooling to 0 ℃ in an ice water bath, dropwise adding a dry mixed solution of Tetrahydrofuran (THF) and benzaldehyde, after dropwise adding, removing the ice water bath until the temperature is recovered to room temperature, and stirring until the raw materials react completely; adding cold ammonium chloride aqueous solution to carry out quenching reaction, extracting by using dichloromethane, washing by using distilled water and saturated saline solution respectively, drying, then carrying out rotary evaporation to remove the solvent to obtain a crude product, using thin-layer chromatography silica gel as a stationary phase, mixing a mixed solvent of dichloromethane and petroleum ether according to a ratio of 1:1, using the mixture as an eluent to carry out gradient elution, collecting eluted components, and carrying out rotary drying by using a rotary evaporator to obtain a white solid target product 2, namely 5,5 '-diphenylmethenyl-2, 2' -bithiophene.

In the step (1), the use amounts of the n-hexane, the tetramethylethylenediamine, the n-hexane solution of n-butyllithium (n-BuLi), 2' -bithiophene, tetrahydrofuran and benzaldehyde are as follows: 52 mL: 4.8 mL: 20mL of: 2.66 g: 20mL of: 3.38g, wherein the concentration of the n-hexane solution of n-butyllithium (n-BuLi) was 1.6 mol/L.

(2) Adding the 5,5 '-diphenylmethylhydroxy-2, 2' -bithiophene obtained in the step (1) into a reaction bottle, under the protection of nitrogen, adding pyrrole into the reaction bottle by using 1, 2-dichloroethane as a solvent, slowly adding boron trifluoride diethyl etherate, performing gradient heating, and refluxing for 11-12 hours; after the reaction is finished, carrying out suction filtration, removing filter residues, washing reactants by dichloromethane, and removing a solvent by rotary evaporation; the product was subjected to crude treatment using a neutral alumina column, dichloromethane was used as eluent, the fractions were collected and the organic solvent was removed by rotary evaporation. Then using thin layer chromatography silica gel as a stationary phase, using a mixed solvent of dichloromethane and petroleum ether (volume ratio is 1:3) as an eluent to carry out gradient elution, and removing the solvent under a reduced pressure condition to obtain a yellow oily target product 3, namely 5,5 '-bis (phenyl-2-pyrryl methyl) -2,2' -bithiophene.

In the step (2), the dosage relationship of 5,5 '-diphenylhydroxy-2, 2' -bithiophene, 1, 2-dichloroethane, pyrrole and boron trifluoride diethyl etherate is 3 mmol: 40mL of: 10mL of: 1.6 mL.

(3) Respectively adding the 5,5 '-bis (phenyl-2-pyrrylmethyl) -2,2' -bithiophene prepared in the step (2) and aromatic aldehyde as raw materials into a reactor, adding dichloromethane as a solvent under the condition of nitrogen protection, adding trifluoroacetic acid, stirring at room temperature in a dark place for 11-12 h, adding 2, 3-dichloro-5, 6-dicyan p-benzoquinone (DDQ), removing nitrogen protection, continuing stirring for 3-4 h, quenching with a saturated sodium bicarbonate solution, extracting with dichloromethane, washing with saturated salt water, drying, removing the solvent in a rotary evaporator under reduced pressure, purifying the compound by silica gel column chromatography, gradient eluting with a mixed solvent of dichloromethane and petroleum ether as an eluent, removing the solvent under reduced pressure by using the rotary evaporator, recrystallizing the obtained compound, obtaining a target product 4, namely an octatomic porphyrin crystal connected by using a cis-bithiophene ring as a construction unit.

In the step (3), the dosage ratio of the 5,5 '-bis (phenyl-2-pyrrylmethyl) -2,2' -bithiophene, the aromatic aldehyde, the trifluoroacetic acid and the DDQ is as follows: 0.38 mmol: 0.4 mmol: 90 μ L of: 0.86 mmol.

The aromatic aldehyde is pentafluorobenzaldehyde, p-nitrobenzaldehyde or p-formylmethyl benzoate.

The octa-porphyrin prepared by the invention and connected by using cis-bithiophene ring as a construction unit is used for detecting Hg in solution²⁺The use of (1).

The octa-porphyrin prepared by the invention is used for detecting Hg in solution²⁺When the ion is used, the octaporphyrin needs to be prepared into 5 multiplied by 10 firstly^-5The solution was in mol/L, at which time the solution was red in color. When the solution to be prepared containing mercury ions is added dropwise into the prepared octa-porphyrin solution, the color of the solution is changed, and the solution is changed from red to blue. The invention has the advantages that:

(1) the purification method of the invention is simple, the experimental process is easy to control, the by-products in the reaction are less, the separation and purification are easy, and the yield is moderate.

(2) The octatomic porphyrin prepared by the invention and connected by taking the cis-bithiophene ring as a construction unit has higher selectivity on metal ions, can be used for pertinently detecting mercury ions in a solution and is not influenced by other metal cations, can be used as a high-efficiency mercury ion sensor, and has better application prospect.

Drawings

FIG. 1 is a MALDI-TOF-Ms mass spectrum of octaporphyrin 4a, the target product in example 1.

FIG. 2 is a MALDI-TOF-Ms mass spectrum of octaporphyrin 4b as a target product in example 2

FIG. 3 is a MALDI-TOF-Ms mass spectrum of octaporphyrin 4c, the target product in example 3

FIG. 4 is the UV-VIS absorption spectra of the target octaporphyrins 4a, 4b, 4c of examples 1,2, 3.

FIG. 5 shows the UV-Vis spectrum change of octaporphyrin 4a of example 1 after different metal cations are added.

FIG. 6 shows the UV-Vis spectrum change of octaporphyrin 4a (mix. times.Ni.) as the target product of example 1 after addition of mixed metal cation solution²⁺+Co²⁺+Cu²⁺+Mg²⁺+Ca²⁺+Zn²⁺+Pb²⁺+K⁺+Na⁺)。

FIG. 7 shows the color of the solution of the target octaporphyrin 4a in example 1 in the presence of different metal cations.

FIG. 8a is the first step in the UV-Vis spectrum change of example 1 after titration of a solution of the target octaporphyrin 4a with a solution of mercury perchlorate in dichloromethane; FIG. 8b is the second step in the UV-Vis spectral change of example 1 after titration of a solution of the target octaporphyrin 4a with a solution of mercury perchlorate in dichloromethane.

Detailed Description

The invention will be further illustrated by the following examples