Photoluminescence Properties Of Small Phenazine Derivatives And Their Influencing Factors

Phenazine is a kind of N-heteroacene derivative with a rigid planar.It has many excellent physical properties,such as luminescence,electrical conductivity,redox activity and stability.In the design of optoelectric functional materials,it becomes one of the most attractive building blocks.It can introduce various functional groups or combine with metal ions to produce functional materials with unique photoelectric properties.A series of phenazine derivatives with adjustable optical properties can be formed by introducing different substituents or the same substituents into different positions.In this thesis,a series of novel phenazine derivatives were synthesized,and their optical properties were characterized.Furthermore,the effects of substituent structures and substituent positions on the molecular stacking modes and photoelectric properties of phenazine derivatives were investigated and the effect of non-covalent bond interactions between molecules on the luminescence of phenazine derivatives were studied as well.Firstly,synthesis and characterization of novel phenazine derivatives.A series of phenazine derivatives with different modified groups were synthesized.The orbital energy levels and electronic structure of the phenazine skeleton were regulated by changing the electronic property and position of the substituents,and then the luminescence properties of the molecules are regulated.In this thesis,six different disubstituted positions（1,4-,1,5-,1,6-,1,8-,2,3-,2,6-）and two modified groups（phenyl and 4-hexyloxy phenyl）were considered to construct the phenazine derivaties.A total of 12 different phenazine derivatives were synthesized and their structures were characterized by ¹H-NMR,¹³C-NMR,MS and single crystal.Meantime,the optical properties such as UV absorption spectral,fluorescence spectral,quantum yields,and lifetimes were characterized.Based on the analysis of its optical properties,the effects of the substituent structures and positions on the luminescent properties were clarified,and the phenazine derivatives with high luminescent efficiencies were obtained.The solutions of 1,4-phenazine derivatives in DCM and the solid of 2,6-phenazine derivatives have relatively strong emissions.The liquid fluorescence quantum yield of1,4-dhpp was 62.84%.The fluorescence emission intensity of 4-hexyloxy phenyl compounds was stronger than that of phenyl phenazine derivatives at the same position.Through the analysis of optical properties,it was found that the phenyl substituted phenazine derivatives had aggregation-induced fluorescence enhancement（AIE）effect,and the hexyloxyphenyl substituted phenazine derivatives had aggregation fluorescence quenching（ACQ）effect.Secondly,exploration of the influence factors for the luminescence properties of phenazine molecules.The luminescence properties of phenazine derivatives were regulated by changing the non-covalent bond interactions between the molecules:1)the influence of solvents.The phenazine derivatives exhibited a distinct solvatochromic effect,and their luminescence colour changed significantly with the increase of the solvent polarity.2)The influence of organic acids.The phenazine derivatives formed hydrogen bonds with the organic acids as hydrogen bond receptors,which affected their luminescence colour,and their luminescence wavelength gradually redshifted with the increase of the organic acidity.3)The influence of porous silica gel supports.The luminescence wavelength of phenazine derivatives loaded on the silica gel all redshifted,and the influence of different types of silica gel（100 mesh,200 mesh,300 mesh）on the optical properties of phenazine derivatives was different.4)Mixing two molecules.Two phenazine derivatives with different luminescence wavelengths were mixed in order to study the influence of the molar ratio of the two phenazine derivatives on the luminescence colour of the mixed solution.The results show that:1)the product of 1,8-dpp has a white-light coordinate CIE of（0.30,0.34）when embedded on 300 mesh silica gel,and the product of 2,6-dpp has a white-light coordinate of（0.33,0.37）in DCM solution mixed with trifluoroacetic acid.The above research results show that the optical properties of phenazine derivatives can be regulated by changing the electronic property and substitution position of the modifying groups.Their optical properties are sensitive to changes in the external environment,and the emission wavelength changes significantly,which can be used in the development of fluorescent sensors.