An approach to the design of non-mutagenic azo dyes

Calogero, Frank; Freeman, Harold S.; Esancy, James F.; Whaley, Wilson M.; Dabney, Betty J.

doi:10.1016/0143-7208(87)85035-0

Cited by 30 publications

(13 citation statements)

References 36 publications

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“…The synthesis of poly[2,2'-bipyridine-5,5'-diyl(2,5-didecoxy-1,4-phenylene)] (PBP) began with the generation 5,5'-diiodo-2,2'-bipyridine (3), 11 as shown in Scheme 2. The commercially available 2-chloro-5-nitropyridine was iodinated and coupled to produce a dinitrobipyridine.…”

Section: Methodsmentioning

confidence: 99%

“…One such report is of poly[2,2'-bipyridine-5,5'-diyl(2,5-dihexyl-1,4-phenylene)] that had an emission maximum around 370 nm. 11 The absorbance maximum of PBP is 370 nm and the emission maximum is 430 nm, with a Stokes shift (∆) of 4300 cm -1 . Also, PBP has a broad shoulder at lower energies for both absorption and emission, as shown in Figures 2(b Photophysical information for polybenzophenones is rare.…”

Section: Polymer Photophysicsmentioning

confidence: 99%

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Triplet energy harvesting by lanthanides in conjugated polymers

2002

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We report the design, synthesis, and spectroscopic characterization of polyphenylene-type polymers that can be used to sensitize europium complexes. Although benzophenone is widely studied and characterized, polybenzophenones have not been widely used in photophysical studies. The properties of poly(4'-methyl-2,4-benzophenone) (MB), poly(4'-methyl-2,5-benzophenone) (PB) and poly[2,2'-bipyridine-5,5'-diyl(2,5-didecoxy-1,4-phenylene)] (PBP) are described in this paper. All three polymers have backbones that are similar to polyphenylene. PBP has a bipyridine unit that alternates with a phenyl ring. Benzophenone rings are polymerized with para or meta linkages in PB and MB, respectively. All three polymers have similar emission maxima at 430 nm, but PBP has a higher quantum efficiency of emission. The polymers studied in this paper proved to be of lower energy than what is needed to sensitize many europium complexes. In almost all of the lanthanide complexes the ligands played a major role in the emission properties. This was elaborated in studies done previously. Europium chelates of the two different ligands: di(2-thienoyl)methane (DTM) and di(2-naphthoyl)methane (DNM) proved to be of comparable energies with the polymers studied. Results showed that energy transfer did occur between the polymers and the europium chelates, but the energy transfer was not 100% because residual emission from the polymers was detected.

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Section: Methodsmentioning

confidence: 99%

Section: Polymer Photophysicsmentioning

confidence: 99%

Triplet energy harvesting by lanthanides in conjugated polymers

2002

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“…1,4-dibromobenzene, 1,3-dibromobenzene, 3,5-dibromobenzoic acid, 2-acetylthiophene, 2-acetylpyrazine and all reagents were purchased from Aldrich. 5,5'-diiodo-2,2'-bipyridine, 4 4'-(3,5-dibromophenyl)-2,2':6',2''-Terpyridine, 5 2,5-didecoylxyphenyl-1,3-bisboronic acid 6 were synthesized according to published procedures. 3,5-dibromobenzoic acid was esterified using ethanol prior to polymerization.…”

Section: Methodsmentioning

confidence: 99%

Efficient energy harvesting of conjugated polymers by direct coordination to novel low-energy complexes of europium

Padmaperuma

Harper

2003

Nanomaterials and Their Optical Applications

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Novel complexes based on europium(III) core surrounded by three β-diketonate ligands were synthesized. The diketonates were synthesized by condensations of ethyl-2-pyrazinecarboxylate with various aromatic ketones. The metal centered emissions of the europium complexes as well as the ligand centered emission of the gadolinium complexes were studied. The complexes based on gadolinium were studied to establish the singlet and triplet energy levels of the ligands. These europium complexes were used to harvest energy from conjugated polymers. PPP-type polymers with bipyridine moieties and terpyridine pendant groups were studied initially. The europium complex attached to the bipyridine and terpyridine moieties facilitated energy transfer from polymer to europium. A novel class of polymers with a β-diketonate pendant group was synthesized and studied. Each of the polymers were synthesized via Suzuki coupling of 1,4-phenylbisboronic acid with a dibromoarenecarboxylate. Ethyl 3,5-dibromobenzoate was used in the polymerization to synthesize alternating copolymers of phenyl groups. These polymers were then reacted with 2-acetylthiophene to obtain polymers with β-diketonate pendant groups. The photophysics of these polymers and their lanthanide complexes were determined.

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“…On ingestion, it produces gastrointestinal irritation with nausea, vomiting and diarrhea. CR is known to be toxic to aquatic and terrestrial ecosystems and is a suspected carcinogen and mutagen due to the generation of benzidine, a compound known to cause bladder cancer in humans [21,22]. Hence, removal of hazardous dye, CR, is significant.…”

Section: Introductionmentioning

confidence: 99%