Cationic porphyrins bearing diazolium rings: synthesis and their interaction with calf thymus DNA

Tjahjono, Daryono Hadi; Akutsu, Takehiro; Yoshioka, Naoki; Inoue, Hidenari

doi:10.1016/s0304-4165(99)00139-7

Cited by 86 publications

(52 citation statements)

References 35 publications

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“…The cobalt-porphyrin precursor, Co(II)-5,10,15,20-tetrakis-(1,3-dimethylimidazolium-2-yl) porphyrin tetrachloride (Co II -TDMImP; Scheme 1) was prepared by metallation of the corresponding free base (29) and characterized by UV-vis, EPR, and mass spectroscopies. The UV-vis spectrum of Co II -TDMImP showed a Soret band at 407 nm and two Q bands at 527 nm and 558 nm (SI Appendix, Fig.…”

Section: Resultsmentioning

confidence: 99%

Efficient water oxidation catalyzed by homogeneous cationic cobalt porphyrins with critical roles for the buffer base

Wang

Groves

2013

Proc. Natl. Acad. Sci. U.S.A.

332

306

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A series of cationic cobalt porphyrins was found to catalyze electrochemical water oxidation to O 2 efficiently at room temperature in neutral aqueous solution. 10,15,porphyrin, with a highly electron-deficient meso-dimethylimidazolium porphyrin, was the most effective catalyst. The O 2 formation rate was 170 nmol·cm −2 ·min −1 (k obs = 1.4 × 10 3 s −1 ) with a Faradaic efficiency near 90%. Mechanistic investigations indicate the generation of a Co IV -O porphyrin cation radical as the reactive oxidant, which has accumulated two oxidizing equivalents above the Co III resting state of the catalyst. The buffer base in solution was shown to play several critical roles during the catalysis by facilitating both redox-coupled proton transfer processes leading to the reactive oxidant and subsequent O-O bond formation. More basic buffer anions led to lower catalytic onset potentials, extending below 1 V. This homogeneous cobalt-porphyrin system was shown to be robust under active catalytic conditions, showing negligible decomposition over hours of operation. Added EDTA or ion exchange resin caused no catalyst poisoning, indicating that cobalt ions were not released from the porphyrin macrocycle during catalysis. Likewise, surface analysis by energy dispersive X-ray spectroscopy of the working electrodes showed no deposition of heterogeneous cobalt films. Taken together, the results indicate that Co-5,10,15,20-tetrakis-(1,3-dimethylimidazolium-2-yl)porphyrin is an efficient, homogeneous, single-site water oxidation catalyst.ater oxidation is a key step in photosynthesis that efficiently harvests and stores solar energy (1). The oxidation of H 2 O to O 2 is a four-electron, four-proton process in which O-O bond formation is the key chemical step. In photosystem II, these proton-coupled electron transfers (PCETs) occur via a tyrosine at the Mn 4 Ca oxygen-evolving complex (2). An important thermodynamic aspect of photosynthesis is the efficient conversion of photonic energy to electrical potential, thus providing 99% of the driving force required to convert CO 2 to carbohydrates (Eqs. 1 and 2):andThe development of synthetic catalysts that can mediate water oxidation under mild conditions with a minimal energy cost has become an appealing challenge for chemists (3-7). Among various approaches, homogeneous molecular catalysts have shown attractive features such as controllable redox properties, ease of investigating reaction mechanisms, and strategies for the characterization of reactive intermediates (8,9). Recently, such efforts have resulted in the development of a significant number of systems based on single-site and multinuclear transition metal complexes including Mn, Fe, Co, Cu, Ru, and Ir (9-15). Examples of cobalt-based molecular catalysts include a cobalt phthalocyanine (16), a cobalt "hangman" corrole (17), multipyridine cobalt complexes (18, 19), a dinuclear Co-peroxo species (20), and most recently, Co-porphyrins (21). Determining if these molecular complexes retain their homogenous nature during catalysis or ...

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Section: Resultsmentioning

confidence: 99%

Efficient water oxidation catalyzed by homogeneous cationic cobalt porphyrins with critical roles for the buffer base

Wang

Groves

2013

Proc. Natl. Acad. Sci. U.S.A.

332

306

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“…Because the relative viscosity of CTDNA with addition of TMPyP in the presence of 0.1 M NaCl increased (data not shown), TMPyP must be actually intercalated. 48,49) In contrast to TMPyP, the conservative asymmetric ICD signal of 1 in the presence of 0.1 M NaCl became more symmetric in the absence of NaCl (Fig. 5b).…”

Section: Discussionmentioning

confidence: 91%

Solution Properties and Photonuclease Activity of Cationic Bis-porphyrins Linked with a Series of Aliphatic Diamines.

Yamakawa

Ishikawa

Uno

2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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The development of efficient photo-induced DNA cleavage agents has been of particular interest for biomedical applications such as cancer photodynamic therapy (PDT). Toward this objective, we synthesized a series of cationic bis-porphyrins with various lengths of diamino alkyl linkage, N,N-bis{4-[10,15,20-tris(1-methylpyridinium-4-yl)porphyrin-5-yl]benzoyl}oligomethylenediamine hexaiodide. They were expected to show more efficient photocleavage of DNA than unichromophore meso-tetrakis(4-N-methylpyridiniumyl)porphine (TMPyP), which is well known to cleave DNA effectively on illumination. The cationic bis-porphyrins were found to self-aggregate in aqueous solution, and the aggregation property was accounted for by the formation of an intermolecular dimer. Because conservative-type circular dichroism spectra of the bis-porphyrins were induced in the Soret region on binding to calf thymus DNA, we assigned their binding mode to outside self-stacking on the DNA surface. Their photonuclease activity using plasmid DNA decreased as the number of their linker hydrocarbons increased, and was well correlated with their tendency for dimerization. The inhibitory effect of azide anion, N 3 ؊ , and the enhancement effect of D 2 O suggest that singlet oxygen was probably involved in the photocleavage of DNA.Key words porphyrin; DNA; photocleavage; aggregation; singlet oxygen plex DNA, and photonuclease activity. We show that these cationic bis-porphyrins formed intermolecular dimers in aqueous solution, and bound to calf thymus DNA (CTDNA) with outside self-stacking. Their photocleavage efficiency of plasmid DNA diminished as the number of their linker hydrocarbons increased, and correlated with their tendency for dimerization. ExperimentalInstrumentation The 1 H-NMR spectra were recorded on a JEOL GX-400 or JNM-A-500 spectrometer. The MALDI-TOF (matrix-assisted laser desorption/ionization time-of-flight) mass spectra (MS) were measured on a Bruker REFLEX TM . The UV-visible absorption measurement was performed on a Beckman DU650 spectrophotometer. The CD spectra were recorded on a JASCO J-720 spectropolarimeter. Elemental analyses were performed at the Analytical Center, Kumamoto University. Materials and MethodsReagents for the synthesis of cationic bis-porphyrins were purchased from Tokyo Kasei Chemical Co. Thionyl chloride was distilled before use. Hexane, methylene chloride, and triethylamine were distilled in the presence of P 2 O 5 .24) 5-(4-methoxycarbonylphenyl)-10,15,20-tris(4-pyridyl)porphine (TPyPCOOCH 3 ) and 5-(4-carboxyphenyl)-10,15,20-tris(4-pyridyl)porphine (TPyPCOOH) were synthesized according to the previous method.25) CTDNA was purchased from Sigma Chemical Co., and the solution was quantitated spectrophotometrically using e 260 ϭ13200 M (base pairs) Ϫ1 · cm Ϫ1 . The tosylate salt of TMPyP was purchased from Dojin Chemical Co.General Procedure for the Synthesis of Non-charged Bis-porphyrins Linked with a Series of Aliphatic Diamines TPyPCOOH (250 mg, 0.378 mmol) was dissolved in 35 ml of thionyl chloride unde...

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“…The synthesis of the new porphyrins derivative studied herein was carried out under Adler-Longo conditions [23] and is detailed reported in Ref. [24].…”

Section: Methodsmentioning

confidence: 99%

Excited-state absorption investigation of a cationic porphyrin derivative

Maximiano

Piovesan

Zílio

et al. 2010

Journal of Photochemistry and Photobiology A: Chemistry

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Cationic porphyrins bearing diazolium rings: synthesis and their interaction with calf thymus DNA

Cited by 86 publications

References 35 publications

Efficient water oxidation catalyzed by homogeneous cationic cobalt porphyrins with critical roles for the buffer base

Efficient water oxidation catalyzed by homogeneous cationic cobalt porphyrins with critical roles for the buffer base

Solution Properties and Photonuclease Activity of Cationic Bis-porphyrins Linked with a Series of Aliphatic Diamines.

Excited-state absorption investigation of a cationic porphyrin derivative

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