Synthesis And Luminescent Properties Of Phenothiazine Derivatives/Metal-Organic Framework Composites

Luminescent organic small molecules are widely used in light-emitting diodes,lasers,sensors,biological imaging and other fields due to their easy modification,unique electronic structure and optical properties.However,the strong interaction between the molecules leads to a decrease in luminescence performance,which limits their development as solid-state luminescent materials.In this paper,a series of novel small molecule phenothiazine(PTZ)derivatives were designed and synthesized,and their luminescence properties were studied.In order to effectively disperse and space the organic molecules and avoid their agglomeration,a composite luminescent materials of host-guest metal organic framework materials(MOFs)based on PTZs small molecules were prepared and their luminescent properties were studied.In the chapter 2,four kinds of D-A phenothiazine derivatives with different molecular lengths and sizes PZCO,PZCN,PZCH,and PZCOO were designed and synthesized.Their photophysical behavior was studied.With the increasing of the solvent polarity,a slightly red shift was observed in the absorption and a huge red shift was observed in the emission spectra.The emission peaks of PZCO,PZCN,PZCH,and PZCOO in solids not only have a larger red shift than their emission peaks in n-hexane,but also the emission spectrum are broaden.This phenomenon indicates that the accumulation of such molecules in the solid state causes serious changes of the luminesce.In order to disperse the luminescent small molecules effectively,ZIF-8 was used as the host material and the phenothiazine derivative were assembled in ZIF-8 to obtain composite materials PZCO/ZIF-8,PZCN/ZIF-8,PZCH/ZIF-8,in which the larger PZCOO guest failed to obtain its host-guest composite.Compared with the solid emission spectra of PZCO,PZCN,and PZCH,a very obvious blue shift was observed in the emission spectra of composite materials PZCO/ZIF-8,PZCN/ZIF-8,and PZCH/ZIF-8.In the chapter 3,two naphthalimide-phenothiazine derivatives,PZONI and PZON4,were designed and synthesied.Theoretical calculations showed that the Naphthalimide(NA)unit and phenothiazine unit in both PZONI and PZON4 molecules have a large twist state.Due to the different substituents in the NA part,a larger twisted structure was observed in PZONI.So in the solid state,compared with PZON4,π-π interaction between PZONI molecules is weaker.As the polarity of the solvent increases,the absorption spectra of PZONI and PZON4 are less red shifted and the emission spectra are more red shifted.The emission peak of PZONI in a solid is only red shifted by 8 nm compared to its emission peak in n-hexane.PZONI has a weaker intermolecular π-π interaction in a solid.A similar comparison shows that the spectral red shift of PZON4 is larger(38 nm),indicating that PZON4 is more heavily packed than PZONI in the solid state.ZIF-8 was used as the host material and the phenothiazine derivative were assembled in ZIF-8 to obtain composite materials PZONI/ZIF-8.Compared with the emission spectrum of PZONI in the solid state,the emission peak of the composite PZONI/ZIF-8 is blue shifted.In the Chapter 4,two anthracene-phenothiazine derivatives PZO9 A and PZO2 A were designed and synthesized.Theoretical calculations showed that in the PZO9 A molecule,showing a "ten" structure,the anthracene(A)unit and the phenothiazine unit have a large degree of twist state,so in the solid state,PZO9 A has weaker intermolecular π-π interaction.Due to the different connection positions of the A part,for PZO2 A,the anthracene unit extends from the molecule,which is conducive to the formation of a strong π-π interaction between the anthracene unit planes in the solid state.With the increasing of the solvent polarity,a red shift was observed in the absorption and the emission spectra of the two compounds,but the red shifted degree of the emission spectrum of PZO9 A is larger.The emission peak of PZO9 A in the solid is smaller than that in n-hexane,the emission spectrum of PZO2 A is obviously red shifted and broadened,indicating that the interaction between PZO2 A molecules in the solid state is stronger.ZIF-8 was used as the host material and the phenothiazine derivative were assembled in ZIF-8 to obtain composite materials PZO9A/ZIF-8,which had a deep blue light emission.