The Synthesis And Characterization Of Biradical Magnetic Materials Based On Perylene Derivatives

In the past few decades,biradical magnetic materials have received extensive attention.Due to their special electronic structure,excellent electron transport properties,and excellent optoelectronic properties,it can be used as the basic structural unit of materials such as organic light-emitting diodes,organic conductors,organic transistors,organic memory materials,and solar photovoltaic panels.Although the development prospect of biradical magnetic molecules is very good,the conditions for the preparation and characterization of biradical materials are very harsh,which limits the application of biradical magnetic molecules in the field of electromagnetism.However,with the vigorous development of society and the increasing demand for organic magnetic materials,the development and preparation of new materials with excellent properties are urgently expected by scientists and researchers.Perylene derivatives are a series of compounds with special structures,which have excellent thermal stability,photostability and chemical stability.Therefore,it is widely used in electron transport materials,organic electroluminescent materials,solar cells,organic photoconductors and other fields.Therefore,scientists and researchers have carried out a lot of research on perylene derivatives.On this basis,this paper prepared and characterized two perylene derivatives,2Per-2N and DA-Per,and studied their optical,electrical and magnetic properties.The main contents are as follows:1.Synthesis and isolation of stable nitrogen-centered bis(imino)perylene dimers in the form of crystals through reactions such as Suzuki-Miyaura coupling reaction and Sonogashira coupling reaction Diradical(2Per-2N).Unlike closed-shell bis(imino)tetrarylene(QR-2N),this single-bond-linked dimer exhibits a larger biradical character due to steric repulsion between quinoid-adjacent perylene units.It is quite stable due to its bulky electronwithdrawing group and large sterically hindered group: 2,4,6-dichlorophenyl group and kinetic blocking effect of efficient electron spin delocalization to the whole perylene unit.On the other hand,it has a small band gap and also exhibits amphiphilic redox and paramagnetism.It is a stable nitrogen free radical conjugated molecule with double radical characteristic index.2.A new push-pull quinoid perylene biradical compound was synthesized: DA-Per,whose first singlet excited state has a larger dipole moment than the ground state,so it shows a negative solvatochromic effect.Notably,its diradical character also exhibits solvent dependence,exhibiting closed-shell properties in strongly polar solvents(dimethyl sulfoxide,methanol,acetone),while in less polar solvents(chloroform,dichloromethane,tetrahydrofuran)showed open-shell properties.Therefore,the delicate balance between the three resonance forms can be manifested in different solvents.DA-Per is a rare solvent polarity-dependent diradical molecule.This provides a new direction and guidance for our future design and characterization of novel molecules.