Hemispherical synthesis of dendritic poly(L-lysine) combining sixteen free-base porphyrins and sixteen zinc porphyrins

Maruo, Naoki; Uchiyama, Motonori; Kato, Tamaki; Arai, T.; Nishino, Norikazu; Akisada, Hideo

doi:10.1039/a906501f

Cited by 40 publications

(20 citation statements)

References 12 publications

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“…A poly(L-lysine) dendrimer that carries 16 free-base porphyrins in one hemisphere and 16 zinc porphyrins in the other one has been synthesized and studied in DMF solution [48]. In such a dendrimer, energy transfer from the Zn-porphyrin units to the free-base ones has been observed to occur with 43% efficiency.…”

Section: Dendrimersmentioning

confidence: 99%

Light‐Harvesting Antennae

2008

Molecular Devices and Machines

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An antenna for light harvesting (Figure 6.1) is an organized multicomponent system in which several chromophoric molecular species absorb the incident light and channel the excitation energy to a common acceptor component [1]. For artificial systems, the term antenna effect was first used [2] to discuss the case of strongly emitting but weakly absorbing lanthanide ions surrounded by strongly absorbing ligands, where the luminescence of the lanthanide ion was sensitized by excitation in the ligand-centered (LC) excited states. Research in this area is still very active [3]. Antenna systems are widely used by Nature to solve the problem of light-harvesting efficiency in the photosynthetic process, where light is converted into chemical energy [4]. Collecting light by an antenna system, however, may also be useful for other purposes, such as signal amplification in luminescence sensors [5], photodynamic cancer therapy [6], and upconversion processes [7]. A large system, where an array of chromophoric units absorb light and transfer energy to a luminescent center, can also be considered a spatial and spectral energy concentrator (molecular lens) [8].The antenna effect can only be obtained in supramolecular arrays suitably organized in the dimensions of time, energy, and space. Each molecular component has to absorb the incident light, and the excited state so obtained (donor) has to transfer electronic energy to a nearby component (acceptor), before undergoing radiative or nonradiative deactivation (organization in the time dimension). For energy transfer to occur, the energy of the acceptor excited state has to be lower or, at most, equal to the energy of the excited state of the donor (organization in the energy dimension). Finally, the successive donor-to-acceptor energy-transfer steps must result in an overall energy-transfer process leading the excitation energy toward a selected component of the array (organization in the space dimension).In the course of evolution, Nature has succeeded in building up antenna systems that fully satisfy the above requirements. In green plants, such natural antennae j135 Molecular Devices and Machines. Concepts and Perspectives for the Nanoworld. 2 nd Ed.

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Section: Dendrimersmentioning

confidence: 99%

Light‐Harvesting Antennae

2008

Molecular Devices and Machines

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“…This prompted the synthesis of dendritic poly( L ‐lysine) 12 , which bears two hemispherically segregated domains comprised of 16 free‐base porphyrin (P FB ) units and 16 zinc porphyrin (P Zn ) units on the exterior surface. A steady‐state fluorescence study has shown the occurrence of a two‐dimensional P Zn ‐to‐P FB energy transfer with a Φ ENT value of 43 % 30. Here, photoexcitation of a certain P Zn unit in compound 12 is followed by an energy migration within the P Zn domain, and then the excitation energy is transferred to a P FB unit at a boundary of the two domains.…”

Section: Dendritic Light‐harvesting Antennaementioning

confidence: 99%

Bioinspired Molecular Design of Light‐Harvesting Multiporphyrin Arrays

et al. 2003

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Recent progress in fundamental studies on multiporphyrin arrays has provided structural parameters for the molecular design of artificial light-harvesting antennae which mimic the wheel-like antenna complexes of photosynthetic purple bacteria. Covalent and noncovalent approaches have been employed for the construction of artificial light-harvesting multiporphyrin arrays. Such arrays are categorized into ring-shaped, windmill-shaped, star-shaped, and dendritic architectures. In particular, dendritic multiporphyrin arrays have been proven to be promising candidates for both providing a large absorption cross-section and enabling the vectorial transfer of energy over a long distance to a designated point. Such molecular and supramolecular systems are also expected to be potent components for molecular electronics and photonic devices.

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“…Dendrimers containing photoactive units [7][8][9][10][11][12][13][14][15][16][17] are particularly interesting for two reasons: (1) cooperation among the photoactive components can allow the dendrimer to perform specific functions, and (2) changes in the properties of photoactive components can be exploited to monitor the participation of dendrimers in chemical processes.…”

Section: -6mentioning

confidence: 99%

Synthesis of Poly(3,4,5-trihydroxybenzoate amide) and Poly(3,4,5-trihydroxybenzoate ester) Dendrimers from Polyphenols and Their Chemiluminescence

Lee¹,

Song²,

Lee³

et al. 2012

Bulletin of the Korean Chemical Society

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Dendrimer chemistry is rapidly expanding for fundamental reasons as well as due to requirements in technological applications.1 A recent interesting development in dendrimer chemistry concerns the coordination of metal ions by interior branches or exterior units. 2-6Dendrimers containing photoactive units 7-17 are particularly interesting for two reasons: (1) cooperation among the photoactive components can allow the dendrimer to perform specific functions, and (2) changes in the properties of photoactive components can be exploited to monitor the participation of dendrimers in chemical processes.Polyphenols such as pyrogallol and gallic acid (GA) produce a singlet oxygen in the presence of hydrogen peroxide in an alkaline medium and emit light. GA has also been utilized for selective Co 2+ detection using a chemiluminescence (CL) flow injection system. The CL intensities of polyphenols are considerably weaker than those of luminal and acridinium ester, which are representative CL compounds. Hence, trans-4-(3-propionic acid) phenylboronic acid and 4-biphenylboronic acid in the presence of peroxidase or 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide have been used as an enhancer for highly sensitive polyphenol CL determination. However, methods to derive polyphenols with strong CL intensity have not been reported yet. 18In recent times, after a new polymer, poly(amidoamine) dendrimer, was synthesized, dendrimers have been applied to material engineering based on optics in nanoscale science. The poly(propylene amine) family that was functionalized in the periphery with fluorescent dansyl units interacts with Co 2+. More recently, acridinium dendrimers have been conjugated with bovine serum albumin, and its CL was estimated to be six times that of the acridinium salt.In this paper, we report the design of new types of polyphenol dendrimers having an increased number of chemiluminophores for high CL intensity; they also have hydroxyl groups in their periphery to form hydrogen bonds with an analyte. Polyphenol dendrimers having GA in the periphery were synthesized, and their CL was measured. We synthesized first-generation polyphenol dendrimers with GA units in the periphery by employing a divergent method using phenol, pyrocatechol, resorcinol, hydroquinone, 1,2,4-trihydroxybenzene, 3,4,5-trihydroxybenzene aniline, 1,2-diaminobenzene, and 1,3-diaminobenzene as the core molecules (Supporting information, Schemes 1 and 2).Experimental methods and physical data from polyol 1a-f to first-generation esters 5a-f have been reported in our previous paper. 19The mass spectra of the zero-generation esters 3a-f and first-generation esters 5a-5f were obtained by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI TOF MS) using 2,5-dihydroxybenzoic acid as the matrix. The amide group has a rigid, planer structure as a consequence of resonance interactions that give the amide bond ~40% double bond character. The planer conformation maximizes π-bonding overlap, which accounts for the amide group's ri...

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Hemispherical synthesis of dendritic poly(L-lysine) combining sixteen free-base porphyrins and sixteen zinc porphyrins

Abstract: Dendritic poly(l-lysine) combining sixteen free-base porphyrins and sixteen zinc porphyrins hemispherically at the fifth generation was successfully synthesised and showed intramolecular fluorescence energy transfer in DMF.

Cited by 40 publications

References 12 publications

Light‐Harvesting Antennae

Light‐Harvesting Antennae

Bioinspired Molecular Design of Light‐Harvesting Multiporphyrin Arrays

Synthesis of Poly(3,4,5-trihydroxybenzoate amide) and Poly(3,4,5-trihydroxybenzoate ester) Dendrimers from Polyphenols and Their Chemiluminescence

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