The NMR Spectroscopic Evaluation of Immobility of a Crowd of Porphyrin Rings Combined with Dendritic Poly(l-lysine)s

Abstract

Since the dendritic poly(l-lysine)s combining eight to thirty-two free base-porphyrins showed split circular dichroism at the Soret band in toluene/N,N-dimethylformamide (9/1, v/v), the immobility of porphyrin rings was evaluated by 1H NMR measurements in terms of the peak width at half-height and spin-lattice relaxation time.

Synthesis of Multiporphyrin Containing Hyperbranched Polymers

“…Furthermore, work within our group developed a noncovalent system using a dendrimer as a scaffold to support a large number of external porphyrins . Other examples include a number of symmetrical porphyrin arrays, − such as the aromatic polyether porphyrin dendrimer prepared by Aida et al − These types of multiporphyrin architectures have been shown to exhibit energy transfer efficiencies of over 90%; however, they are limited by the time-consuming nature of the synthesis involved.…”

Formation of Submicron Scale Particles of Narrow Size Distribution from a Water-Soluble Dendrimer with Links to Porphyrins and a Fullerene

“…Synthesis of a Water-Soluble Dendrimer with a Porphyrin − Fullerene System. An l -lysine dendrimer was chosen to attach to the porphyrin−fullerene system in this study because it is a typical and well-characterized dendrimer and can easily be incorporated with various functional groups. , We have synthesized both the porphyrin-linked l -amino acid, ( N -α-( tert -butoxycarbonyl)- N ‘ -ε-(4-(tritolylporphyrin-5-yl)benzoyl)- l -lysine), 27a, and the fullerene-linked l -amino acid, ( l -2-( tert -butoxycarbonylamino)-8-(fulleropyrrolidinyl)octanoic acid), in enantiomeric pure forms to be used as monomers for the l -amino acid dendrimers. Mimicking the recent report on the porphyrin−fullerene system,13c we adopted a system with a pair of porphyrins and a fullerene (Scheme ).…”

“…Scheme outlines the synthesis of a water-soluble dendrimer 6 . The core is the fullerene-containing l -amino acid 1 , which connected NH−(CH 2 ) 6 −NHCO 2 CH 2 Ph at the C-terminal as a potential linker to a certain functional group in the future.…”

“…Compound 1 (0.11 g, 84 μmol) was treated with TFA−CH 2 Cl 2 (1:1, by volume, 10 mL) at 0 °C for 1 h. After evaporation, ether was added to solidify the Boc-removed derivative of 1 (TFA salt). This sample and Boc-Lys(Boc)-OH (42 mg, 0.12 mmol) , were dissolved in 10 mL of DMF with the aid of sonication. The mixture was ice-chilled, HOBt·H 2 O (18 mg, 0.12 mmol), HBTU (45 mg, 0.12 mmol), and DIEA (21 μL, 0.12 mmol) were added, and the mixture was stirred overnight at room temperature, when the unreacted Boc-removed derivative of 1 disappeared on a silica gel TLC (CHCl 3 −5% MeOH).…”

Dendrimer Porphyrins and Phthalocyanines

“…[121][122][123][124][125][126] In addition, more complex system 29a has been reported (Chart 11), which possesses 16 zinc porphyrin (P Zn ) units on one hemisphere and 16 free-base porphyrin (P FB ) units on the other hemisphere of a fifthgeneration poly(L-lysine) dendrimer. 127,128 Photoexcitation of the P Zn units results in energy transfer to the P FB units with an efficiency of 43%. As a reference compound, dendrimer 29b, which contains randomly mixed P Zn and P FB units on the dendrimer surface, shows a much higher energy transfer efficiency (85%).…”