Photoketonization of dibenzoylmethane in polar solvents

Yankov, P.; Saltiel, S.; Петков, Иван

doi:10.1016/0009-2614(86)80665-0

Cited by 12 publications

(4 citation statements)

References 6 publications

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“…The DNA binding of AVBH and 1 – 6 was investigated by UV–visible spectroscopy, and the absorption spectra were recorded in the presence of increasing amounts of calf thymus DNA (ct-DNA) (Figure S11 in the Supporting Information). The spectrum of avobenzone possesses a wide band near 370 nm, due to a π–π* transition of the enol form, with a shoulder near 380 nm and a weak band near 270 nm corresponding respectively to the n−π* and π–π* transitions of the keto form. − Complexes 1 – 6 display intense absorptions due to the enol form of bonded avobenzone, shifted in the range 330–350 nm, together with a week band at 280–290 nm and a shoulder at 380 nm. Moreover, in the case of 1 and 2 a hypochromism is observed, accompanied by a small red shift of the band at 330–350 nm, whereas for 3 – 6 there is negligible hypochromism without any red shift.…”

Section: Resultsmentioning

confidence: 99%

From Sunscreen to Anticancer Agent: Ruthenium(II) Arene Avobenzone Complexes Display Potent Anticancer Activity

Pettinari¹,

Marchetti²,

Petrini³

et al. 2016

Organometallics

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A series of ruthenium(II) arene derivatives (arene = cymene (cym), hexamethylbenzene (hmb)) containing avobenzone (1-(4-tert-butylphenyl)-3-(4-methoxyphenyl)propane-1,3-dione, AVBH) and PTA (1,3,5-triaza-7-phosphaadamantane) or PTA-Me (N-methyl-1,3,5-triaza-7-phosphaadamantane cation) have been synthesized and fully characterized. Three types of complexes have been obtained: i.e., neutral [Ru(arene)(AVB)Cl] (1, arene = cym; 2, arene = hmb), monocationic [Ru(arene)(AVB)(PTA)][SO3CF3] (3, arene = cym; 4, arene = hmb), and dicationic [Ru(arene)(AVB)(PTA-Me)][SO3CF3][BF4] (5, arene = cym; 6, arene = hmb). The solid-state structures of 1 and 2 were determined by single-crystal X-ray diffraction. The cytotoxicity of the complexes has been evaluated in vitro against human ovarian carcinoma cells, A2780 and A2780cisR, as well as against nontumorous Human Embryonic Kidney (HEK293) cells. The ionic complexes with hydrophilic PTA and PTA-Me ligands in 3–6 are considerably more active than the neutral complexes 1 and 2

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Section: Resultsmentioning

confidence: 99%

From Sunscreen to Anticancer Agent: Ruthenium(II) Arene Avobenzone Complexes Display Potent Anticancer Activity

Pettinari¹,

Marchetti²,

Petrini³

et al. 2016

Organometallics

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“…The second observation is that in PEAA, in contrast to previous our results in solution, 6 the pho- been known. [2][3][4][5] It is sure that such isomerization The figures show the decrease in absorbance under direct UV irradiation proceeds at the excited singlet state. 10 The basic requirement for such process is the possibility the excited enol molecule to rotate around C|C double bond.…”

Section: Resultsmentioning

confidence: 99%

Photochemical behavior of poly(ethylacryloylacetate) and poly(acryloylacetone) films

Masuda

Sertova

Петков

1997

J. Polym. Sci. A Polym. Chem.

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“…79 Several examples of photoketonization have also been reported in the literature. [75][76][77][78] For example, Yankov et al have shown that the keto form of dibenzoylmethane (Fig. 3.6), which is unstable in the ground state, is formed upon photoexcitation.…”

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confidence: 99%

“…Since the tautomeric equilibria in excited states can be very different from those in the ground state, it is in many cases possible to induce an isomerization between two tautomeric forms by light. [72][73][74][75][76][77][78][79] Already in 1961, Yang and Rivas showed that the keto form of ortho-methylbenzophenone (Fig. 3.6) can undergo excited-state tautomerism into the corresponding enol form in alcohol solutions.…”

mentioning

confidence: 99%

Computational Studies of Photobiological Keto-Enol Reactions and Chromophores

Falklöf¹

2015

Linköping Studies in Science and Technology. Dissertations

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This thesis presents computational chemistry studies of keto-enol reactions and chromophores of photobiological significance.The first part of the thesis is concerned with two protein-bound chromophores that, depending on the chemical conditions, can exist in a number of different ketonic and enolic forms. The first chromophore is astaxanthin, which occurs in the protein complex responsible for the deep-blue color of lobster carapace. By investigating how different forms of astaxanthin absorb UV-vis radiation of different wavelengths, a model is presented that explains the origin of the dramatic color change from deep-blue to red upon cooking of live lobsters.The second chromophore is the oxyluciferin light emitter of fireflies, which is formed in the catalytic center of the enzyme firefly luciferase. To date, there is no consensus regarding which of the possible ketonic and enolic forms is the key contributor to the light emission. In the thesis, the intrinsic tendency of oxyluciferin to prefer one particular form over other possible forms is established through calculation of keto-enol and acid-base excited-state equilibrium constants in aqueous solution.The second part of the thesis is concerned with two families of biological photoreceptors: the blue-light-absorbing LOV-domain proteins and the red-lightabsorbing phytochromes. Based on the ambient light environment, these proteins regulate physiological and developmental processes by switching between inactive and active conformations. In both families, the conversion of the inactive into the active conformation is triggered by a chemical reaction of the respective chromophore.The LOV-domain proteins bind a flavin chromophore and regulate processes such as chloroplast relocation and phototropism in plants. An important step in the activation of these photoreceptors is a singlet-triplet transition between two electronically excited states of the flavin chromophore. In the thesis, this transition is used as a prototype example for illustrating, for the first time, the ability of first-principles methods to calculate rate constants of inter-excited state phosphorescence events.Phytochromes, in turn, bind bilin chromophores and are active in the regulation of processes like seed germination and flowering time in plants. Following two systematic studies identifying the best way to model the UV-vis absorption iii iv and fluorescence spectra of these photoreceptors, it is demonstrated that steric interactions between the chromophore and the apoprotein play a decisive role for how phytochromes are activated by light. Populärvetenskaplig sammanfattningSolljusär en förutsättning för liv på jorden. Växter använder solljus som energikälla för att kunna bilda näring till sig själva ochäven syre till andra organismer. Iögonen hos människor och djur finns specialdesignade celler som omvandlar ljus till elektriska impulser, som sedan tolkas till en bild av syncentrat i hjärnan. Djur har utvecklat mekanismer för att med hjälp av ljus kunna kamouflera sig, locka till s...

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Photoketonization of dibenzoylmethane in polar solvents

Cited by 12 publications

References 6 publications

From Sunscreen to Anticancer Agent: Ruthenium(II) Arene Avobenzone Complexes Display Potent Anticancer Activity

From Sunscreen to Anticancer Agent: Ruthenium(II) Arene Avobenzone Complexes Display Potent Anticancer Activity

Photochemical behavior of poly(ethylacryloylacetate) and poly(acryloylacetone) films

Computational Studies of Photobiological Keto-Enol Reactions and Chromophores

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