312260-71-2Relevant academic research and scientific papers
Trans beta substituted chlorins and methods of making and using the same
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, (2008/06/13)
Trans beta substituted chlorins and methods of making the same are disclosed, along with polymers formed from or containing such trans beta substituted chlorins as one or more monomeric units therein, light harvesting rods formed from such polymers, and e
Rational synthesis of β-substituted chlorin building blocks
Balasubramanian,Strachan,Boyle,Lindsey
, p. 7919 - 7929 (2007/10/03)
Chlorins bearing synthetic handles at specific sites about the perimeter of the macrocycle constitute valuable building blocks. We previously developed methodology for preparing meso-substituted chlorin building blocks and now present methodology for preparing several complementary β-substituted chlorin building blocks. The chlorins bear one or two β substituents, one meso substituent, a geminal dimethyl group to lock in the chlorin hydrogenation level, and no flanking meso and β substituents. The synthesis involves convergent joining of an Eastern half and a Western half. New routes have been developed to two β-substituted bromo-dipyrromethane monocarbinols (Eastern halves). A new β-substituted Western half was prepared following the method for preparing an unsubstituted Western half (3,3-dimethyl-2,3-dihydrodipyrrin). Chlorin formation is achieved by a two-flask process of acid-catalyzed condensation followed by metal-mediated oxidative cyclization, β-Substituted chlorins have been prepared in 18-24% yield bearing a 4-iodophenyl group at the 8-position, a 4-iodophenyl group or a 4-[2-(trimethylsilyl)ethynyl]phenyl group at the 12-position, and a 4-iodophenyl group and a 4-[2-(trimethylsilyl)ethynyl]phenyl group at diametrically opposed β-positions (2, 12). The latter building block makes possible the stepwise construction of linear multi-chlorin architectures. The chlorins exhibit typical absorption and fluorescence spectra. A systematic shift in the absorption maximum (637-655 nm for the free base chlorins, 606-628 nm for the zinc chlorins) and intensity of the chlorin Q(y) band (ε up to 79 000 M-1 cm-1) is observed depending on the location of the substituents. The characteristic spectral features and location of substituents in defined positions make these chlorins well suited for a variety of applications in biomimetic and materials chemistry.
