Synthesis Of 4a-Indacene Essay
The syntheses of 8-(4-(decyloxy) phenyl)-1, 3, 5, 7-tetramethyl-2, 6 dibromo-4-bora, 3a, 4a-diaza-s-indacene and 8-(4-(decyloxy) phenyl)-1, 3, 5, 7-tetramethyl-2, 6 diiodo-4-bora, 3a, 4a-diaza-s-indacene both commence with the synthesis of 4-(decyloxy) benzaldehyde. Following standard procedures and using the resulting aldehyde, along with 2,4-dimethylpyrole, a BODIPY dye was obtained [36]. To facilitate intersystem crossing, the 2- and 6- positions of the boradiazaindacene ring system were iodinated with an iodic acid-iodine mixture [37]. Bromination at the same positions was performed via N-bromosuccinamide (NBS) [38]. 8-Palmitoyl-1, 3, 5, 7-tetramethyl-2, 6 diiodo-4-bora, 3a, 4a-diaza-s-indacene was obtained by the iodination of 8-palmitoyl-1, 3, 5,
…show more content…
7-tetramethyl-4-bora, 3a, 4a-diaza-s-indacene which was synthesized from 4-decyloxy benzaldehyde and 2,4-dimethylpyrole [36] (Scheme 1). Hydrophobic moieties were provided by long alkyl chains and amphiphilic units by Chromophore EL. All products are water soluble. Photo-induced singlet oxygen generation was determined by the photobleaching of the chemical probe 9, 10-anthracenediyl-bis(methylene)dimalonic acid (ABMDMA), a water- soluble derivative of anthracene that can be photobleached by singlet oxygen to its corresponding endoperoxide. The reaction was monitored spectrophotometrically by recording the decrease in absorbance at 377 nm. In a typical experiment, ABMDMA in a water solution with a maxium absorbance of 1 was mixed with M3, M4, or M6 to give a final concentration of 1 μM.
The control experiment involved using ABMDMA with a maximum absorbance of 1 in water. The solutions were irradiated in an open quartz cuvette by continuous stirring. The absorbance measurements followed by irradiation were taken every 5 min. A 520 nm green LED lamp was used as the light source.The absorbance spectrum of ABMDMA in water showed that the absorbance stayed constant for 30 minutes (Figure 2). Figure 3 shows the absorbance changes of 9,10-anthracenediyl bis(methylene)dimalonic acid alone and M3 with 9,10-anthracenediyl bis(methylene)dimalonic acid in an aqueous solution as a function of irradiation time. No change in the absorbance occurred in the trap molecule either in light or dark, though the absorbance of the M3-trap molecule solution decreased under light due to the interaction of trap molecule with singlet oxygen at 377 nm. It is well known that photosensitizers used in PDT can be photobleached, followed by the loss of absorbance, fluorescence and photoactivity. As shown, M3 is clearly photo-stable with only a minor change in absorbance (16
%).
The absorbance of M4 with the trap molecule solution at 377 nm shows a sharp decrease after 20 minutes (Figure 4.). The better performance of M4 can be explained by iodine substitutions at the 2 and 6 positions which display a heavy atom effect.
As shown in Figure 5, measurements using ABMDMA showed a significant decrease in absorbance at 377 nm for M6 with ABMDMA following irradiation which suggests high efficiency in the generation of reactive singlet oxygen.
7-tetramethyl-4-bora, 3a, 4a-diaza-s-indacene which was synthesized from 4-decyloxy benzaldehyde and 2,4-dimethylpyrole [36] (Scheme 1). Hydrophobic moieties were provided by long alkyl chains and amphiphilic units by Chromophore EL. All products are water soluble. Photo-induced singlet oxygen generation was determined by the photobleaching of the chemical probe 9, 10-anthracenediyl-bis(methylene)dimalonic acid (ABMDMA), a water- soluble derivative of anthracene that can be photobleached by singlet oxygen to its corresponding endoperoxide. The reaction was monitored spectrophotometrically by recording the decrease in absorbance at 377 nm. In a typical experiment, ABMDMA in a water solution with a maxium absorbance of 1 was mixed with M3, M4, or M6 to give a final concentration of 1 μM.
The control experiment involved using ABMDMA with a maximum absorbance of 1 in water. The solutions were irradiated in an open quartz cuvette by continuous stirring. The absorbance measurements followed by irradiation were taken every 5 min. A 520 nm green LED lamp was used as the light source.The absorbance spectrum of ABMDMA in water showed that the absorbance stayed constant for 30 minutes (Figure 2). Figure 3 shows the absorbance changes of 9,10-anthracenediyl bis(methylene)dimalonic acid alone and M3 with 9,10-anthracenediyl bis(methylene)dimalonic acid in an aqueous solution as a function of irradiation time. No change in the absorbance occurred in the trap molecule either in light or dark, though the absorbance of the M3-trap molecule solution decreased under light due to the interaction of trap molecule with singlet oxygen at 377 nm. It is well known that photosensitizers used in PDT can be photobleached, followed by the loss of absorbance, fluorescence and photoactivity. As shown, M3 is clearly photo-stable with only a minor change in absorbance (16
%).
The absorbance of M4 with the trap molecule solution at 377 nm shows a sharp decrease after 20 minutes (Figure 4.). The better performance of M4 can be explained by iodine substitutions at the 2 and 6 positions which display a heavy atom effect.
As shown in Figure 5, measurements using ABMDMA showed a significant decrease in absorbance at 377 nm for M6 with ABMDMA following irradiation which suggests high efficiency in the generation of reactive singlet oxygen.