| Photodynamic therapy is an effective method for therapy cancer and non-cancer diseases.The photosensitizers are key to photodynamic therapy.Phthalocyanine photosensitizers are a promising second-generation photosensitizer.However,the hydrophobic planar structure of phthalocyanine makes its easy to aggregation leading to the fluorescence quench.The absorption of phthalocyanine is maily existed in the range of 640-690nm,whose tissue penetration depth is limited,and it cannot destroyed the deep tumors.Near-infrared(NIR-Ⅰ)region(700-850nm)light could be less absorbed and scattered by tissues,not only could significantly,increased the penetration depth,but also lower the background signal,which is expected to enhance the photodynamic therapy efficacy However,there are few examples on the substituted zinc phthalocyanine photosensitizers in the NIR-Ⅰ region.In this paper,a series of zinc phthalocyanine with anilinate substituted groups complexes were synthesized by introducing halogenated aniline groups and triphenylamine/benzocarbazole groups to the peripheral/non-peripheral position of zinc the phthalocyanine ring.On the one hand,the donor aniline group directly connected with the zinc phthalocyanine,which makes the Q-band absorption peak of zinc phthalocyanine red shifted to the NIR-Ⅰ region.On the other hand,the triphenylamine/benzocarbazole structure is further coupled with halogenated aniline group leading to futher expand the conjugation system,which lead the Q-band absorption of zinc phthalocyanine further red shifted.At the same time,the spatial hindrance of triphenylamine/benzocarbazole groups could improve the aggregation behavior of phthalocyanine to some extend.The main contents are as follows:(1)A series of precursors were synthesized using nitrophthalonitrile and halogenated phenylboronic acid as substrates,through molybdenum-catalyzed carbon-nitrogen coupling reaction.These precursors are 4-(p-bromoaniline)phthalonitrile,3-(p-bromoaniline)phthalonitrile and 4-(3,4,5-trifluoroaniline)phthalonitrile.Then,three haloanilinated zinc phthalocyanines were obtained by cyclozation of precursors using nitrobenzene as solven.Three haloanilinated zinc phthalocaynines are tetra-β-4-bromoaniline zinc phthalocyanine(4-Br),tetra-α-4-bromoaniline zinc phthalocyanine(3-Br)and tetra-β-(3,4,5-trifluoroaniline)zinc phthalocyanine(4-3F).The structure of these phthalocaynines were characterized by FT-IR,~1H-NMR,ESI-MS as well as MALDI-TOF-MS.The photophysical and photochemical properties of the haloanilinated zinc phthalocyanines were also compared:Q-band absorption peak and emission peak of zinc phthalocyanine(4-Br,3-Br,4-3F)were located in the NIR-Ⅰ region,and the Q-band absorption peaks of 4-Br,3-Br,4-3F were located at 719nm,767nm,709nm,respectively,with high molar absorption coefficient and wide half wave width.The emission spectra of4-Br,3-Br,4-3F were also appeared in the NIR-Ⅰ region,at 729nm,785nm,719nm,respectively.The fluorescence quantum yield,fluorescence lifetime and singlet oxygen quantum yield of three phthalocyanines are compared.3-Br has the highest fluorescence quantum yield and singlet oxygen quantum yield,but shortest fluorescence lifetime.Compared withβ-substituted phthalocyanine(4-Br),the Q-band absorption and emission peaks ofα-substituted phthalocyanine 3-Br are further red shifted,which may be related to the intramolecular hydrogen bond formed betweenα-substituted anilinated proton and nitrogen atom on the phthalocyanine ring,which enhances the interaction between aniline group and the central ring and gives stronger electron donor conjugation effect.(2)Six triphenylamine/benzocarbazole substituted amino zinc phthalocyanine were synthesized by introducing three triphenylamine/benzocarbazole substituents intoαorβposition of zinc phthalocyanine via reductive molybdenum catalyzed coupling reaction.The six triphenylamine/benzocarbazole substituted amino zinc phthalocyanine are tetra-β-triphenylamine zinc phthalocyanine(A1),tetra-α-p-triphenylamine zinc phthalocyanine(A2),tetra-β-phenylcarbazole-3-amino zinc phthalocyanine(B1),tetra-α-9-phenylcarbazole-3-aminozincphthalocyanine(B2),tetra-β-(m-carbazole)aniline phthalocyanine(C1),tetra-α-(m-carbazole)aniline phthalocyanine(C2).The structures of these compounds were also determined by~1H-NMR,ESI-MS,MALDI-TOF-MS and FT-IR.(3)The photophysical properties,singlet oxygen quantum yield and aggregation induced emission of triphenylamine/benzocarbazole substituted amino zinc phthalocyanine were studied by UV-vis,steady-state/transient fluorescence and chemical capture mothed.The Q-band absorption peak of triphenylamine/benzocarbazole substituted amino zinc phthalocyanines were further red shifted after introducing the triphenylamine/benzocarbazole substituents to the 4-Br and 3-Br structures.The Q-band absorption peak and emission peak of the A1-C2 were located in the NIR-Ⅰ region.The position of Q-band absorption peak showed substituent position and substituent structure dependence:compared withβ-amino substituted phthalocyanine,Q-band absorption peak position ofα-amino substituted phthalocyanine red-shift obviously,which is related to the formation of intramolecular hydrogen bond between the amino matrix ofα-position substituted phthalocyanine and the nitrogen atom of phthalocyanine ring,which could expand the conjugation system.With the same substitution position,the 9-benzocarbazole-3-groups conjugated with the phthalocyanine ring formed the largest conjugation system for B2 possesed,which lead to the most obviously red-shift of Q band;the conjugation system between triphenylamine and phthalocyanine ring in A2 is realtively small,which is mainly due to the freedom rotation of the triphenylamine molecule,the redshift of Q-band is smaller to B2.For C2,carbazolphenyl rings is easy to rotate freely,m-carbazolphenyl and phthalocyanine conjugation system is smaller.Thereby,the red shift of Q-band is the smallest.The maximum emission peaks of the A1-C2 are all in the NIR-Ⅰ region.The position of fluorescence emission also shows substituent position and structure dependence,and they exhibited a mirror relationship with UV-Vis spectrum.Comparing the fluorescence quantum yield,fluorescence lifetime and singlet oxygen quantum yield of A1-C2,it is found that C2 has the highest fluorescence quantum yield,fluorescence lifetime and singlet oxygen quantum yield,B2can produce singlet oxygen under 808nm laser irradiation.Therefore,B2 and C2 are promising NIR-Ⅰ photosensitizers.At last,the aggregation induced luminescence effect of A1 and A2 was studied. |
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