Regulation Of The Spin Density Distribution In Conjugated Diradicals

In recent years,organic radical materials have attracted more and more interest in the fields of organic electronics and spintronics due to their unique properties of unpaired electron(s).The characteristics of diradicals,such as reversible redox,low energy band gap and strong secondary polarizability,make it important in the application of electronics,nonlinear optics and energy storage.For radical based materials,their properties can be heavily influenced by spin density distribution.Therefore,the regulation of spin distribution is an important means to alter the material properties.Until now,several methods to regulate the spin distribution of free radicals have been reported.For example,by extending or shortening the conjugate length of molecules,introducing heteroatoms,and using topological symmetry.but the related research is still rare.Moreover,to the best of our knowledge,no studies have been conducted to regulate the spin distribution through external stimuli(such as temperature,light and magnetic field.).Therefore,we have designed diradicals with the well-known azobenzene,which not only can realize cis-trans transformation under irradiation,but also the azobenzene has bicycle pedal motion in the solid state under thermal treatment.Overall,we have studied the relationship between temperature,irradiation and the spin distribution of radicals.1.Diradicals was prepared by the combination of azobenzene core with phenoxy radical.By measuring the single crystal structure of designed molecule at temperatures from 130 to 340 K,two different conformational transition processes were found.With the help of advanced theoretical calculations,it was confirmed that the bicycle pedal motion of azobenzene in the solid state had a regulatory effect on the spin distribution of the molecule.In addition,the UV-vis absorption spectra,electrochemical properties,spin properties and solid Raman spectra were characterized respectively.2.The effect of photoisomerization on the spin distribution of diradicals have been studied by designing molecule with the combination of an azobenzene part with two phenoxyl moieties,which connected via a nitrogen atom.The molecule has been full characterized by UV-vis spectroscopy,cyclic voltammetry and spin related spectroscopy.