Synthesis Of Aromatic Amine Ferrocene Salts And Study On Its Photoinitiated Epoxy System

Aromatic ferrocene salt is a kind of metal complex that absorbs in the visible light region.Because it will undergo photolysis under light,the aromatic hydrocarbon is removed and Fe²⁺ is exposed.This ion is a strong Lewis acid and can be used as a cation.Type photoinitiator initiates the photopolymerization of vinyl and epoxy monomers.However,the molar absorption coefficient above 300 nm is low,and the matching effect with the commonly used LED lamp source is poor,and the polymerization conversion rate of initiating epoxy monomer is low.The performance of aromatic ferrocene salt is mainly affected by the aromatic ligand coordinated with its cyclopentenyl iron ion.As small aromatic amine molecules,triphenylamine and carbazole not only have good electron donating properties and good charge Transmission capacity,also showed excellent optical performance.Therefore,this work designs the combination of electron-rich carbazole and triphenylamine groups with CpFe+,which can not only enhance the charge transfer ability of the ferrocene salt,but also make it have more excellent optical properties and high initiation activity.In this thesis,a carbazole-triphenylamine coupling product 4,4’-（9H-carbazole-3,6-diyl）bis（N,N-diphenylamine）was first synthesized by Suzuki coupling reaction,and then passed The nucleophilic substitution reaction of chlorophenylferrocene,a ferrocene salt[（η⁶-（4,4’-（9 phenyl-carbazole-3,6-diyl）bis（N,N-diphenylamine）））-Iron-（η5-cyclopentadienyl）)]hexafluorophosphate（TPACzFc）,which conforms to the structural design of D（donor molecule）-A（acceptor molecule）.In order to further study the effect of aromatic amine ligands on the properties of ferrocene salts,four ferrocene salts containing aromatic amine ligands were synthesized,namely[（η⁶-triphenylamine）-iron-（η5-cyclopentadienyl）))]hexafluorophosphate（TPAFc）,[（η⁶-（N-ethylcarbazole））-iron-（η5-cyclopentadienyl）)]hexafluorophosphate（NECzF c）,[（η⁶（N-phenylcarbazole））-iron-（η5-cyclopentadienyl）)]hexafluorophosphate（NPCzF c）,[（η⁶-（1,4-bis（9H-carbazole-9-yl））Benzene）)-iron-（η5-cyclopentadienyl）)]hexafluorophosphate（DCzFc）.The structure of the synthesized compound was characterized by FTIR and ¹H-NMR.In order to study the photophysical properties of the arylamine ferrocene salt,the UV-vis absorption spectra of the five synthesized ferrocene salt compounds were tested,and the results showed that the triphenylamine and carbazole coupling ligand was introduced into the aryl ferrocene salt structure Among them,TPACzFc exhibits higher optical performance.Compared with the other four ferrocene salts,the maximum absorption wavelength of TPACzFc is red-shifted to 332 nm,and the corresponding molar absorption coefficient has increased.This thesis also discusses five aromatic amines.The fluorescence emission spectra of the ferrocene salt compound was tested,The fluorescence emission peak of TPACzFc has a more red shift Obviously,the main absorption peak can reach 415 nm;and its fluorescence quantum yield has also increased compared with the other four ferrocene salts.In order to further explore the optical activity of ferrocene salts,UV-vis absorption spectroscopy and fluorescence emission spectroscopy were used to study the photolysis behavior of five aromatic amine ferrocene compounds synthesized under a mercury nail lamp.The results showed that the five ferrocene salts All have a faster photolysis rate,among which TPACzFc is almost completely photodegraded in about 15 s.Through Density functional Theory,the optimal spatial structure and molecular frontier orbitals of the synthesized ferrocene salts were calculated,and It is verified that five ferrocene salts are easily excited by light and have certain intramolecular charge transfer.With 365 nm LED light source as the light source,the cationic photopolymerization of the synthesized five aromatic amine ferrocene salts on the bifunctional ERL4221 epoxy monomer was investigated by RT-FTIR method.The five kinds of ferrocene salts have high photo initiating activity and have good performance as a cationic photoinitiator.Among them,TPACzFc can reach 75%epoxy conversion rate in 80s.Adding a certain amount of BPO in the process of ferrocene salt-initiated epoxy polymerization can effectively increase the polymerization rate and degree of polymerization.Studies have shown that BPO will oxidize Fe²⁺into Fe3+during the ferrocene salt initiation stage,making it have more empty orbitals.It is more conducive to coordinate with the epoxy monomer,thereby accelerating the photopolymerization rate of ERL4221 initiated by it and increasing the epoxy conversion rate of the epoxy monomer initiated by the ferrocene salt.