Preparation,Structure-activity And Biological Application Of Pyridine Triphenylamine Fluorescent Probes

Compared with single photon absorption,two-photon absorption is a process of long-wave absorption short-wave emission.The excitation light is in the biological window period(600 nm?900 nm),which can effectively reduce the dissipation and damage caused by the absorption of excitation light by the medium.In addition,two-photon absorption has superior application prospects in the fields of optical information processing,optical computer and laser medicine.Triphenylamine has a unique propeller-type non-planar molecular structure.The nitrogen atom contains three benzene rings of the same physical environment,which facilitates the formation of branches and flexibly changes the number of branches on the aromatic ring,and thus is a good signal group.It is widely used in new organic light-emitting materials and two-photon materials.In this thesis,triphenylamine is used as the parent,and the secondary photon Schiff base or secondary amine derivative with different recognition effects is obtained by functional group modification such as formylation,nucleophilic substitution and addition reduction,and the long-wavelength region is obtained.Strong luminescence ability and suitable two-photon absorption cross section(5)resulting two-photon fluorescence probes were used for corresponding cell development studies.1.The compound W5-W8 was synthesized by using triphenylamine as the electron-donating group and the styrene group as the ? bridge extension conjugated system.The addition of-C=N-or-NH-and the pyridine ring or the o-hydroxybenzene ring were introduced by addition reduction.For the purpose of water solubility,the compound W1-W2 was prepared by introducing an ether bond by a substitution reaction and introducing an addition reaction to-C=N-.We confirmed their structure using nuclear magnetic resonance spectroscopy,infrared spectroscopy and mass spectrometry.At the same time,we studied their properties using UV and fluorescence visible spectra and theoretical calculations.Among them,the compound W5-W8 provides a clear idea for understanding the structural and functional relationship.In the mixed aqueous solution,the probes W1-W4 have an enhanced fluorescence response to GSH,but different recognition mechanisms.Among them,W1-W2 is hydrolyzed by glutathione to form an amino derivative to emit different fluorescence to complete the recognition behavior,and W3-W4 detects glutathione by in situ substitution method by means of metal ions.Considering toxicity and biocompatibility,W1-W4 take advance for detecting GSH endogenously and exogenously in living cells.2.The triphenylamine is used as the electron donating group,the styryl group is a ?bridge extended conjugated system,and then 1-bromo-2-methylpyridine and 4-diethyl-2-aminosalicylaldehyde are separately introduced to synthesize a novel triphenylamine adjacent hydroxyl group multi-functional probe Y.The structure was characterized by NMR,IR and MS.The identification mechanism of the probe was studied by nuclear magnetic titration and mass spectrometry.The results show that the probe Y can selectively recognize Zn2+ in DMSO solution,and in the mixed solution of water,we also unexpectedly found that probe Y can detect Zn2+/P2O74-in a secondary manner.Furthermore,probe Y also exhibits a two-photon fluorescence"on-off" response with a large effective two-photon absorption cross section of 240 GM,which combines low toxicity with moderate light stability,making Y a two-photon fluorescence probe.A good candidate for the microscope to monitor fluctuations in exogenous Zn2+.3.The triphenylamine is used as the electron-donating group,the styryl group is a?-bridge extended conjugated system,and a plurality of recognition sites such as a secondary amine or an ether bond are obtained by nucleophilic substitution and reduction reaction,and a triphenylaminopyridine fluorescent probe L is synthesized.The structure was characterized by NMR,IR and MS.The photochemical properties and recognition mechanism of the probe were analyzed by UV and fluorescence spectroscopy.The results show that the probe L can visually detect copper ions in a mixed solution of tetrahydrofuran and selectively recognize homocysteine(Hcy)with high selectivity,forming an "on-off-on" type recognition mode.At the same time,the probe L has good biocompatibility and a suitable two-photon absorption cross section,which can be applied to two-photon fluorescence confocal microscopy and monitor Cu2+ and Hcy in living cells.