Two close structurally related isomers of nonaromatic meso‐fused dicarbahexaphyrins were synthesized by condensing one equivalent of fluorene based tripyrrane with one equivalent of pentafluorobenzaldehyde in CH2Cl2 under BF3.OEt2 catalyzed conditions. The cis and trans isomers of meso‐fused dicarbahexaphyrins were separated by preparative thin‐layer chromatography and isolated pure macrocycles as green solids in 6–7% yields. NMR spectra of cis and trans isomers are quite distinct from each other and trans isomer was very symmetric and showed fewer resonances than cis isomer in NMR. The NMR study supported the nonaromatic nature of both cis and trans isomers of meso‐fused dicarbahexaphyrins. DFT optimized structures revealed that the cis isomer adopted a singly twisted puckered conformation whereas the trans isomer displayed a saddle like conformation. Both cis and trans isomers almost showed similar nonaromatic absorption features with slight differences in their peak maxima. However, the protonated derivative of cis isomer showed absorption bands in visible‐NIR region with bands extended upto 1000 nm whereas the trans isomer showed strong bands in the visible region. Both cis and trans macrocycles were easier to oxidize and reduce and TD‐DFT studies corroborated with the experimental findings.
Diethyl chlorophosphate (DCP), an organophosphate, is utilized as a pesticide, herbicide, and for various other applications. Despite many uses of organophosphates, the organophosphates are noxious and harmful substances, and their selective detection is a critical concern in the context of the environment, physiology, and social security. In a methodological quest, here we have synthesized two Schiff base compounds 1 and 2 by introducing the hydroxyl group at the α-position of 3-pyrrolyl BODIPY either directly as hydroxylamine 1 or at the ortho position of aryl ring as 2-aminophenol 2. Both compounds 1 and 2 exhibited high selectivity and high sensitivity for DCP over other pesticides in the aqueous-alcoholic medium at physiological pH. This occurs via nucleophilic phosphorylation of the hydroxyl group, which resulted in both compounds exhibiting two different optical signals following the structurefunction correlation of the pyrrolyl BODIPY systems. Upon binding DCP, compound 1 showed a quenching in the optical spectrum because of phosphorylation of hydroxyl group whereas compound 2 exhibited enhancements in both absorption and fluorescence spectra because of hydroxyl phosphorylation followed by intramolecular cyclization. Furthermore, the fluorescent microscopy experiments also indicated that the compound could be used as a fluorescent compound for sensing DCP in plant tissues.
A new dye called the [Formula: see text]-perimidinyl 3-pyrrolyl BODIPY(PPyBODIPY) was synthesized readily by treating [Formula: see text]-formyl 3-pyrrolyl BODIPY with 1,8-diamino naphthalene in ethanol at reflux. The PPyBODIPY was thoroughly characterized and studied by HR-MS, 1D n 2D NMR, absorption, fluorescence and DFT/TDDFT techniques. The PPyBODIPY absorbs strongly in the 500-600 nm region and emits weakly in the region of 550–650 nm with low quantum yield. DFT optimized structure of PPyBODIPY revealed that the 3-pyrrolyl BODIPY unit was almost planar and the perimidinyl moiety was oriented at 78.88[Formula: see text] relative to appended pyrrole of 3-pyrrolyl BODIPY unit. The photophysical studies revealed that the PPyBODIPY acts as AIEgen and showed aggregation-induced emission behavior in a 60% H2O-THF mixture.
A series of cis-difunctionalized 21-telluraporphyrins containing two functionalized meso-aryl groups such as [Formula: see text]-iodophenyl, [Formula: see text]-bromophenyl, [Formula: see text]-cyanophenyl, [Formula: see text]-nitrophenyl and [Formula: see text]-trimethylsilyl ethynylphenyl groups in cis-fashion were synthesized by condensing one equivalent of 16-telluratripyrrin with two equivalents of functionalized benzaldehyde and three equivalents of pyrrole in CH2Cl2 under acid catalyzed porphyrin forming conditions. The cis-difunctionalized 21-telluraporphyrins were thoroughly characterized by HR-MS, 1D and 2D NMR, and absorption spectroscopic techniques. To show the use of cis-difunctionalized 21-telluraporphyrin building blocks, the covalently linked (BODIPY)2-telluraporphyrin triad was synthesized by coupling cis-diiodophenyl 21-telluraporphyrin with meso-ethynylphenyl BODIPY under Pd(0) coupling conditions and afforded (BODIPY)2-telluraporphyrin triad in 24% yield. The NMR and absorption studies of the triad indicated that the telluraporphyrin and BODIPY moieties interact weakly in the (BODIPY)2-telluraporphyrin triad and retain their individual characteristic features. The steady-state fluorescence and DFT studies indicated a possibility of charge transfer between 21-telluraporphyrin and BODIPY units in the triad.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.