CN-121974933-A - Multi-wavelength excitation near-infrared resonance Raman probe molecule, preparation method thereof, nano-particle and application

Abstract

The invention belongs to the technical field of detection, in particular to a multi-wavelength excited near-infrared resonance Raman probe molecule, a preparation method thereof, nano particles and application, the invention designs and synthesizes two donor-acceptor-donor Raman probes BTA1 and BTA2, the probe has a planarized molecular structure, is highly conjugated along the alkynyl direction, and the donor-acceptor-donor structure effectively promotes intramolecular charge transfer, so that the absorption spectrum is red-shifted to a near infrared region, and meanwhile, the molecular fluorescence is obviously reduced. In addition, the planar molecular configuration enhances intermolecular pi-pi stacking effect, induces strong aggregation-induced fluorescence quenching effect, and further inhibits fluorescence emission. The synergistic effect of pi electron delocalization and aggregation-induced fluorescence quenching of the molecular skeleton is benefited, and BTA1 and BTA2 have strong Raman signals under 488, 532, 633 and 785 nanometer excitation, and show excellent compatibility with commercial laser light sources.

Inventors

• LI MENGYANG
• LIN XIAOBIN

Assignees

• 西北农林科技大学

Dates

Publication Date

20260505

Application Date

20260127

Claims (10)

1. 1. A multi-wavelength excited near-infrared resonance Raman probe molecule is characterized in that the molecule is obtained by Stille cross-coupling reaction of a thiophene stannane derivative and a benzobisthiadiazole derivative; the structural formula of the thiophene stannane derivative is shown as formula I or formula II, wherein formula I is Formula II is ; The structural formula of the benzobisthiadiazole derivative is shown as a formula III, wherein the formula III is 。
2. 2. The multi-wavelength excited near infrared resonance raman probe molecule according to claim 1, wherein the structural formula is shown in formula IV or formula V: Formula IV is ; V is 。
3. 3. A method of preparing a multi-wavelength excited near-infrared resonance raman probe molecule according to claim 1, comprising the steps of: In a nitrogen atmosphere, tetrahydrofuran is used as a solvent, butyl lithium is used as alkali, and an alkynyl thiophene derivative and tributyl tin chloride are subjected to a stannation reaction to obtain a thiophene stannane derivative; in a nitrogen atmosphere, chlorobenzene is used as a solvent, bis (triphenylphosphine) palladium dichloride and cuprous iodide are used as catalysts, and Stille cross-coupling reaction is carried out on the thiophene stannane derivative and the benzobisthiadiazole derivative, so that the multi-wavelength excited near infrared resonance Raman probe molecule is obtained.
4. 4. The preparation method according to claim 3, wherein the alkynyl tin alkylation reaction is carried out under the conditions that the temperature is 85 ℃ to 70 ℃ and the temperature is 15 ℃ to 25 ℃ and the mixture is stirred for 6 hours to 15 hours.
5. 5. The preparation method according to claim 3, wherein the Stille cross-coupling reaction is carried out under the condition of 60-80 ℃ and stirring for 8-15 h.
6. 6. The method according to claim 3, wherein the molar ratio of the alkynylthiophene derivative to the tributyl tin chloride is 2.8-3.3:3.5-3.8.
7. 7. The method according to claim 3, wherein the molar ratio of the benzobisthiadiazole derivative to the alkynylthiophene derivative is 0.8-1.3:2.8-3.3.
8. 8. A nanoparticle prepared by using the multi-wavelength excited near-infrared resonance raman probe molecule according to claim 1, wherein the nanoparticle is obtained by wrapping the multi-wavelength excited near-infrared resonance raman probe molecule with an amphiphilic copolymer DSPE-PEG2000 by a nano precipitation method.
9. 9. Use of the nanoparticle of claim 8 in raman imaging.
10. 10. The use according to claim 9, wherein the nanoparticle is used for imaging of a staining marker of apple tree canker.

Description

Multi-wavelength excitation near-infrared resonance Raman probe molecule, preparation method thereof, nano-particle and application Technical Field The invention belongs to the technical field of detection, and particularly relates to a multi-wavelength excitation near-infrared resonance Raman probe molecule, a preparation method thereof, nanoparticles and application thereof. Background As a characteristic vibrational scattering spectrum of molecules, raman spectrum can provide detailed information on the molecular level, and has become a powerful tool in the fields of bioimaging, analysis and information storage. To fully exploit this potential, the development of molecular probes with raman activity is a key research direction. However, the inherent raman scattering cross section of the vibrating probe is extremely small, which severely restricts the application of spontaneous raman scattering imaging. In order to break through the limitation, research is mainly advanced along two parallel paths, namely, a signal amplification platform such as stimulated Raman scattering, coherent anti-Stokes Raman scattering and surface-enhanced Raman scattering is developed, and a Raman molecule with a strong intrinsic signal is designed. Although nonlinear optical technology (stimulated raman scattering/coherent anti-stokes raman scattering, etc.) brings about revolutionary improvement in imaging speed and signal intensity, the device popularity is limited, while surface-enhanced raman scattering technology is limited by inherent factors such as sensitivity reproducibility challenges, larger nanoparticle size, biocompatibility problems, etc. Therefore, the current research focus is increasingly turned to the construction of novel raman probes, which can be independently used for high-sensitivity spontaneous raman imaging and can be seamlessly integrated with the aforementioned enhancement platform to realize unprecedented signal amplification. Resonance raman scattering, which realizes intrinsic signal amplification (102-10 6 times) by matching excitation wavelength with electron transition of a reporter group, is a powerful signal enhancement strategy. However, the development of resonant raman probes suitable for excitation by visible or near infrared light requires strong donor-acceptor conjugated systems, which often produce strong fluorescent background under resonance excitation, which tend to drown out the target raman signal. Disclosure of Invention In order to solve the technical problems, the invention provides a multi-wavelength excitation near-infrared resonance Raman probe molecule, a preparation method thereof, nano particles and application. A multi-wavelength excited near-infrared resonance Raman probe molecule is obtained by Stille cross-coupling reaction of a thiophene stannane derivative and a benzobisthiadiazole derivative; the structural formula of the thiophene stannane derivative is shown as formula I or formula II, wherein formula I is Formula II is; The structural formula of the benzobisthiadiazole derivative is shown as a formula III, wherein the formula III is。 The invention synthesizes two donor-acceptor-donor Raman probes BTA1 and BTA2, the probes have a flattened molecular structure and are highly conjugated along the alkynyl direction. The donor-acceptor-donor structure effectively promotes intramolecular charge transfer, so that the absorption spectrum is red-shifted to a near infrared region, and meanwhile, the molecular fluorescence is obviously reduced. In addition, the planar molecular configuration enhances intermolecular pi-pi stacking effect, induces strong aggregation-induced fluorescence quenching effect, and further inhibits fluorescence emission. The synergistic effect of pi electron delocalization and aggregation-induced fluorescence quenching of the molecular skeleton is benefited, and BTA1 and BTA2 have strong Raman signals under 488, 532, 633 and 785 nanometer excitation, and show excellent compatibility with commercial laser light sources. Specifically, the alkynyl vibration signal of the raman silence region can be efficiently excited by visible light, while the double bond vibration signal can realize resonance enhancement under 785 nm excitation. Preferably, the structural formula of the multi-wavelength excited near-infrared resonance Raman probe molecule is shown as formula IV or formula V: Formula IV is ; V is。 The preparation method of the multi-wavelength excited near-infrared resonance Raman probe molecule comprises the following steps: In a nitrogen atmosphere, tetrahydrofuran is used as a solvent, butyl lithium is used as alkali, and an alkynyl thiophene derivative and tributyl tin chloride are subjected to a stannation reaction to obtain a thiophene stannane derivative; In a nitrogen atmosphere, chlorobenzene is used as a solvent, bis (triphenylphosphine) palladium dichloride and cuprous iodide are used as catalysts, and the thiophene stannane derivative and