Design of Photoactivated DNA Oxidizing Agents: Synthesis and Study of Photophysical Properties and DNA Interactions of Novel Viologen‐Linked Acridines

Joseph, Joshy; Eldho, Nadukkudy V.; Ramaiah, Danaboyina

doi:10.1002/chem.200304936

Cited by 51 publications

(18 citation statements)

References 56 publications

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“…In the case of dye 9 b , a similar transient absorption spectrum was observed with bands at λ =320 and 460 nm that formed upon excitation with λ =355 nm laser (Figure S28 in the Supporting Information). Triplet quantum yields of 9 a and 9 b were determined by using triplet–triplet energy transfer to β‐carotene with tris(bipyridyl)ruthenium(II) complex as a reference (Table ) …”

Section: Resultsmentioning

confidence: 99%

Carbazole‐Linked Near‐Infrared Aza‐BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep‐Tissue Imaging

Gawale

Adarsh

Kalva

et al. 2017

Chemistry A European J

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Four new N-ethylcarbazole-linked aza-boron-dipyrromethene (aza-BODIPY) dyes (8 a,b and 9 a,b) were synthesized and characterized. The presence of the N-ethylcarbazole moiety shifts their absorption and fluorescence spectra to the near-infrared region, λ≈650-730 nm, of the electromagnetic spectrum. These dyes possess strong molar absorptivity in the range of 3-4×10 m cm with low fluorescence quantum yields. The triplet excited state and singlet oxygen generation of these dyes were enhanced upon iodination at the core position. The core-iodinated dyes 9 a,b showed excellent triplet quantum yields of about 90 and 75 %, with singlet oxygen generation efficiency of about 70 and 60 % relative to that of the parent dyes. Derivatives 8 a,b showed dual absorption profiles, in contrast to dyes 9 a,b, which had the characteristic absorption band of aza-BODIPY dyes. DFT calculations revealed that the electron density was spread over the iodine and dipyrromethene plane of 9 a,b, whereas in 8 a,b the electron density was distributed on the carbazole group and dipyrromethene plane of aza-BODIPY. The uniqueness of these aza-BODIPY systems is that they exhibit efficient triplet-state quantum yields, high singlet oxygen generation yields, and good photostability. Furthermore, the photoacoustic (PA) characteristics of these aza-BODIPY dyes was explored, and efficient PA signals for 8 a were observed relative to blood serum with in vitro deep-tissue imaging, thereby confirming its use as a promising PA contrast agent.

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Section: Resultsmentioning

confidence: 99%

Carbazole‐Linked Near‐Infrared Aza‐BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep‐Tissue Imaging

Gawale

Adarsh

Kalva

et al. 2017

Chemistry A European J

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“…With the exception of methyl viologen, which is commercially available, all other paraquat and bis(pyridinium) citromide salts (G2•2Br-G14•2Br) were prepared by literature methods. 16b,33, 34 The hexafluorophosphate salts were precipitated from water by the addition of saturated aqueous NH 4 PF 6 and recrystallized before use.…”

Section: Methodsmentioning

confidence: 99%

Complex interactions of pillar[5]arene with paraquats and bis(pyridinium) derivatives

et al. 2010

Org. Biomol. Chem.

269

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The complexation behavior of a series of paraquats (G1.2PF(6)-G5.2PF(6)) and bis(pyridinium) derivatives (G6.2PF(6)-G14.2PF(6)) with pillar[5]arene (P5A) host has been comprehensively investigated by (1)H NMR, ESI mass and UV-vis absorption spectroscopy. It is found that P5A forms 2 : 1 external complexes with N,N'-dialkyl-4,4'-bipyridiniums (G1-G4.2PF(6)); while it forms 1 : 1 pseudorotaxane-type inclusion complexes with methylene [-(CH(2))(n)-] linked bis(pyridinium) derivatives possessing appropriate chain lengths (n = 3-6, G7-G10.2PF(6)). Host-guest association constants in dimethyl sulfoxide (DMSO) were determined, indicating G7-G10.2PF(6) axles form stable [2]pseudorotaxanes with P5A wheel in this very high polarity solvent and 1,4-bis(pyridinium)butane (G8.2PF(6)) was the most suitable axle unit. Meanwhile, the nature of the substituents attached to 1,4-bis(pyridinium)butane dramatically affects the molecular recognition behavior. The introduction of pyridyls (G13.2PF(6)) increases not only the K(a) value (4.5 x 10(2) --> 7.4 x 10(2) M(-1)), but also the charge transfer (CT) absorption (colorless --> yellow). Furthermore, the solvent effects have also been investigated, showing they significantly influence the association strength during the course of host-guest complexation. Particularly, the K(a) value of P5A-G13.2PF(6) in 1 : 1 (v:v) acetone-d(6)/DMSO-d(6) is enhanced by a factor of 7.3 compared with pure DMSO-d6 (7.4 x 10(2) --> 5.4 x 10(3) M(-1)).

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“…Of these systems, the imidazolium‐bridged derivatives CP‐1 and CP‐2 exhibited moderate fluorescence quantum yields in the range Φ f = 0.1–0.6, whereas the viologen‐bridged cyclophane CP‐3 showed significantly quenched fluorescence yields. The efficient quenching of fluorescence observed in the case of CP‐3 has been attributed to the existence of thermodynamically favorable photoinduced electron transfer process from the excited singlet state of the anthracene chromophore to the viologen moiety as characterized by laser flash photolysis studies (40–42). Compared with CP‐2 and CP‐3 , the symmetric cyclophane CP‐1 in the aqueous medium exhibited dual emission consisting of a structured band having λ max at 430 nm and a broad band centered at 550 nm with an I 550 / I 430 ratio of 0.8 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Effect of Bridging Units on Photophysical and DNA Binding Properties of a Few Cyclophanes

Neelakandan¹,

Sanju²,

Ramaiah³

2010

Photochem & Photobiology

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A few novel anthracene-based cyclophanes CP-1, CP-2 and CP-3 were synthesized and their interactions with DNA were investigated employing photophysical and biophysical techniques. In methanol and acetonitrile, these systems exhibited optical properties characteristic of the anthracene chromophore. However, in the aqueous medium, the symmetric cyclophane CP-1 showed a dual emission having lambda(max) at 430 and 550 nm, due to the monomer and excimer, respectively. In contrast, the cyclophanes CP-2 and CP-3 in the aqueous medium showed structured anthracene absorption and emission spectra similar to those obtained in methanol and acetonitrile. DNA binding studies indicate that CP-1 undergoes efficient nonclassical partial intercalative interactions with DNA resulting in the exclusive formation of a sandwich-type excimer having enhanced emission intensity and lifetimes. The cyclophane CP-2 having one anthracene moiety exhibited nonclassical intercalative binding with DNA, albeit with less efficiency compared with CP-1. In contrast, CP-3, having sterically bulky viologen bridging group showed DNA electrostatic as well as groove binding interactions. These results demonstrate that the nature of the bridging unit plays an important role in the binding mode of the cyclophanes with DNA and in the formation of the novel sandwich-type excimer.

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Design of Photoactivated DNA Oxidizing Agents: Synthesis and Study of Photophysical Properties and DNA Interactions of Novel Viologen‐Linked Acridines

Cited by 51 publications

References 56 publications

Carbazole‐Linked Near‐Infrared Aza‐BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep‐Tissue Imaging

Carbazole‐Linked Near‐Infrared Aza‐BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep‐Tissue Imaging

Complex interactions of pillar[5]arene with paraquats and bis(pyridinium) derivatives

Effect of Bridging Units on Photophysical and DNA Binding Properties of a Few Cyclophanes

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