A design strategy for (porphinato)zinc-based fluorophores that possess large near infrared fluorescence quantum yields is described. These fluorophores are based on a (5,15-diethynylporphinato)zinc(II) framework and feature symmetric donor or acceptor units appended at the meso-ethynyl positions via benzo[c][1,2,5]thiadiazole moieties. These (5,15-bis(benzo[c][1′,2′,5′]thiadiazol-4′-ylethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (4), (5,15-bis[4′-(N,N-dihexylamino) benzo[c][1′,2′,5′]thiadiazol-7′-ylethynyl]-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (5), (5,15-bis([7′-(4″-n-dodecyloxyphenylethynyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (6), (5,15-bis([7′-([7″-(4″ ′-n-dodecyloxyphenyl)benzo[c][1″,2″,5″]thiadiazol-4″-yl]ethynyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (7), 5,15-bis ([7′-(4″-N,N-dihexylaminophenylethynyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (8), and (5,15-bis([7′-(4″-N,N-dihexylaminophenylethenyl)benzo[c][1′,2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-dimethyl-1″-butyloxy)phenyl]porphinato)zinc(II) (9) chromophores possess red-shifted absorption and emission bands that range between 650 and 750 nm that bear distinct similarities to those of the chlorophylls and structurally related molecules. Interestingly, the measured radiative decay rate constants for these emitters track with the integrated oscillator strengths of their respective x-polarized Q-band absorptions, and thus define an unusual family of high quantum yield near infrared fluorophores in which emission intensity is governed by a simple Strickler–Berg dependence.
本文介绍了一种具有较大近红外荧光量子产率的(卟吩)
锌基荧光团的设计策略。这些荧光团以(5,15-二
乙炔基卟吩基)
锌(II)框架为基础,通过苯并[c][1,2,5]
噻二唑分子在中
乙炔基位置附加对称的供体或受体单元。这些(5,15-双(苯并[c][1′,2′,5′]
噻二唑-4′-
乙炔基)-10,20-双[2′,6′-双(3″,3″-二甲基-1″-丁氧基)苯基]卟吩)
锌(II)(4)、(5、15-双[4′-(N,N-二己基
氨基)苯并[c][1′,2′,5′]
噻二唑-7′-
乙炔基]-10,20-双[2′,6′-双(3″,3″-二甲基-1″-丁酰氧基)苯基]卟吩)
锌(II) (5), (5、15-双([7′-(4″-正
十二烷氧基苯乙炔基)苯并[c][1′,2′,5′]
噻二唑-4′-基]
乙炔基)-10,20-双[2′,6′-双(3″,3″-二甲基-1″-丁酰氧基)苯基]卟吩)
锌(II) (6)、(5,15-双([7′-([7″-(4″′-正
十二烷氧基苯基)苯并[c][1″,2″,5″]
噻二唑-4″-基]
乙炔基)苯并[c][1′,2′,5′]
噻二唑-4′-基]
乙炔基)-10、20-双[2′,6′-双(3″,3″-二甲基-1″-丁酰氧基)苯基]卟吩)
锌(II)(7)、5,15-双([7′-(4″-N,N-二己基
氨基
苯乙炔基)苯并[c][1′,2′、5′]
噻二唑-4′-基]
乙炔基)-10,20-双[2′,6′-双(3″,3″-二甲基-1″-丁酰氧基)苯基]卟吩)
锌(II) (8),以及 (5,15-双([7′-(4″-N,N-二己基
氨基
苯乙炔基)苯并[c][1′、2′,5′]thiadiazol-4′-yl]ethynyl)-10,20-bis[2′,6′-bis(3″,3″-二甲基-1″-丁酰氧基苯基]卟吩)
锌(II)(9)发色团具有红移吸收带和发射带,波长在 650 纳米到 750 纳米之间,与叶绿素和结构相关分子的吸收带和发射带非常相似。有趣的是,这些发射体的辐射衰减速率常数与它们各自的 x 偏振 Q 波段吸收的集成振荡器强度相一致,从而定义了一个不寻常的高量子产率近红外荧光团家族,其中的发射强度受简单的斯特里克勒-伯格依赖关系支配。