Photochemistry of azide-moiety containing inorganic compounds

Šíma, Jozef

doi:10.1016/j.ccr.2006.03.004

Cited by 40 publications

(36 citation statements)

References 51 publications

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“…This can arise from loss of N 2 from the {Pt-N 3 } fragment upon irradiation with UVA. [6] Two electrons are transferred from guanine to the nitrene, and the guanine itself is oxidized to give 8-OH-G on addition of H 2 O. The nitrene is reduced and finally forms the ammine adduct {Pt-NH 3 }.…”

Section: Methodsmentioning

confidence: 99%

“…A reasonable source of the NH 3 is the {Pt-N 3 } fragment, which can lose N 2 upon irradiation with light to form a {Pt-N} nitrene intermediate. [6] This postulation was verified by using 1*, azide trans,trans,- Figure S5 in the Supporting Information. The molecular weight of compound 1 a* was 1 Da larger than 1 a, thus suggesting that it has an intact N 3 * À ligand.…”

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confidence: 99%

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De Novo Generation of Singlet Oxygen and Ammine Ligands by Photoactivation of a Platinum Anticancer Complex

Zhao

Farrer

et al. 2013

Angewandte Chemie

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

De Novo Generation of Singlet Oxygen and Ammine Ligands by Photoactivation of a Platinum Anticancer Complex

Zhao

Farrer

et al. 2013

Angewandte Chemie

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“…[2] Metal azido complexes are poised to be exploited in a similar manner [3] and NMR spectroscopy has the potential to play a central role in characterising and understanding their rich chemical [4] and photochemical [5] properties. Whereas main-group azides are used primarily as detonators, [6] azido coordination compounds with stabilising ligands, large counterions [7] and an overall low reactive nitrogen content are stabilised to the point where they can be considered for a wider range of applications.…”

Section: Introductionmentioning

confidence: 99%

Probing Platinum Azido Complexes by ¹⁴N and ¹⁵N NMR Spectroscopy

Farrer

Gierth

Sadler

2011

Chemistry A European J

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Metal azido complexes are of general interest due to their high energetic properties, and platinum azido complexes in particular because of their potential as photoactivatable anticancer prodrugs. However, azido ligands are difficult to probe by NMR spectroscopy due to the quadrupolar nature of (14)N and the lack of scalar (1)H coupling to enhance the sensitivity of the less abundant (15)N by using polarisation transfer. In this work, we report (14)N and (15)N NMR spectroscopic studies of cis,trans,cis-[Pt(N(3))(2)(OH)(2)(NH(3))] (1) and trans,trans,trans-[Pt(N(3))(2)(OH)(2)(X)(Y)], where X=Y=NH(3) (2); X=NH(3), Y=py (3) (py=pyridine); X=Y=py (4); and selected Pt(II) precursors. These studies provide the first (15)N NMR data for azido groups in coordination complexes. We discuss one- and three-bond J((15)N,(195)Pt) couplings for azido and am(m)ine ligands. The (14)N(α) (coordinated azido nitrogen) signal in the Pt(IV) azido complexes is extremely broad (W(1/2)≈2124 Hz for 4) in comparison to other metal azido complexes, attributable to a highly asymmetrical electric field gradient at the (14)N(α) atom. Through the use of anti-ringing pulse sequences, the (14)N NMR spectra, which show resolution of the broad (14)N(α) peak, were obtained rapidly (e.g., 1.5 h for 10 mM 4). The linewidths of the (14)N(α) signals correlate with the viscosity of the solvent. For (15) N-enriched samples, it is possible to detect azido (15)N resonances directly, which will allow photoreactions to be followed by 1D (15)N NMR spectroscopy. The T(1) relaxation times for 3 and 4 were in the range 5.7-120 s for (15)N, and 0.9-11.3 ms for (14)N. Analysis of the (1)J((15)N,(195)Pt) coupling constants suggests that an azido ligand has a moderately strong trans influence in octahedral Pt(IV) complexes, within the series 2-pic

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“…HSA damage was enhanced in D 2 To determine the contribution of 1 O 2 generation and ET mechanism, a scavenger effect on HSA damage was investigated. HSA photodamage by Cl 2 P(V)TPP was partially inhibited by sodium azide (NaN 3 ) (Figure 4), a physical quencher of 1 O 2 [13], supporting the contribution of 1 O 2 mechanism to HSA damage. However, HSA damage was not completely inhibited by an excess amount of NaN 3 (10 mM), suggesting that the ET mechanism is partly responsible for HSA photodamage, as is the 1 O 2 mechanism.…”

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confidence: 62%

Photosensitized oxidative damage of human serum albumin by water-soluble dichlorophosphorus(V) tetraphenylporphyrin

Ouyang¹,

Hirakawa²

2015

Rapid Communication in Photoscience

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Biomolecular photo-damaging activity of a watersoluble cationic porphyrin was examined using human serum albumin (HSA), a water-soluble protein as a target biomolecule model by a fluorometry. Dichlorophosphorus(V) tetraphenylporphyrin (Cl 2 P(V)TPP), was synthesized and used as a photosensitizer. This porphyrin could bind to HSA and cause the photosensitized oxidation of HSA through the singlet oxygen generation and the oxidative photo-induced electron transfer (ET). Near infrared emission spectroscopy demonstrated the photosensitized singlet oxygen generation by this porphyrin. Decrement of the fluorescence lifetime of Cl 2 P(V)TPP by HSA supported the ET mechanism. Furthermore, the estimated Gibb's energy indicated that the ET mechanism is possible in the terms of energy. Because oxygen concentration in cancer cell is relatively low, ET mechanism is considered to be advantageous for photosensitizer of photodynamic therapy.Porphyrins have been used as the drugs for photodynamic therapy (PDT), which is a less invasive treatment of cancer [1,2]. The oxidation of biomolecules is the major mechanism of PDT. It is triggered by singlet oxygen ( 1 O 2 ) generation or photo-induced electron transfer (ET). Biomolecule oxidation by 1 O 2 is considered as the main mechanism of PDT, however, the low concentration of oxygen in cancer cells restricts the PDT effect [3,4]. Therefore, ET mechanism might become a more important mechanism of PDT in the future. The ET mechanism requires highly oxidative activity (a lower reduction potential) in the photoexcited state of the photosensitizer. Larger excitation energy is advantageous for the lower reduction potential of the photosensitizer in the photoexcited state. Indeed, ultra-violet photosensitizers mainly induce biomolecule photodamage through the ET mechanism, whereas a visible-light photosensitizer is not appropriate for this mechanism [5]. Therefore, an appropriate molecular design to achieve ET mediated biomolecule damage using a visible-light photosensitizer is important. Since highvalent porphyrin complexes demonstrate a lower reduction potential in their photoexcited state than free-base or low-valent metal complexes, these porphyrins are advantageous for the oxidative ET reaction [5][6][7]. For example, in this research, a synthesized porphyrin, Cl 2 P(V)TPP (Figure1) was used.

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Photochemistry of azide-moiety containing inorganic compounds

Cited by 40 publications

References 51 publications

De Novo Generation of Singlet Oxygen and Ammine Ligands by Photoactivation of a Platinum Anticancer Complex

De Novo Generation of Singlet Oxygen and Ammine Ligands by Photoactivation of a Platinum Anticancer Complex

Probing Platinum Azido Complexes by ¹⁴N and ¹⁵N NMR Spectroscopy

Photosensitized oxidative damage of human serum albumin by water-soluble dichlorophosphorus(V) tetraphenylporphyrin

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Photochemistry of azide-moiety containing inorganic compounds

Cited by 40 publications

References 51 publications

De Novo Generation of Singlet Oxygen and Ammine Ligands by Photoactivation of a Platinum Anticancer Complex

De Novo Generation of Singlet Oxygen and Ammine Ligands by Photoactivation of a Platinum Anticancer Complex

Probing Platinum Azido Complexes by 14N and 15N NMR Spectroscopy

Photosensitized oxidative damage of human serum albumin by water-soluble dichlorophosphorus(V) tetraphenylporphyrin

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Probing Platinum Azido Complexes by ¹⁴N and ¹⁵N NMR Spectroscopy