Photoreduction of aminobenzophenones. Effects of solvent on intersystem crossing.

Cohen, Saul G.; Saltzman, Martin D.; Guttenplan, Joseph B.

doi:10.1016/s0040-4039(01)88685-8

Cited by 10 publications

(12 citation statements)

References 8 publications

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“…Triethylamine (pK 10.7) is a much stronger base than is pyridine (pK 5.2). The tri-n-butyl amine and the 4The same effect has been noted for fluorenone (8)(9)(10) quinuclidine also cause a rise in the benzoin and a fall off in the benzoin benzoate similar to that caused by triethylamine. The pyridine however, shows no increase in the benzoin nor any fall in the benzoin benzoate.…”

Section: Resultsmentioning

confidence: 68%

“…There has been much recent work on the photolysis of various benzophenones and of fluorenone using tertiary amines as solvents and hydrogen donors (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). This work has shown that those ketones which do not undergo photoreduction in 2-propanol because the lowest lying excited state is unreactive toward hydrogen abstraction, are photoreduced in triethylamine and other tertiary amines.…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively the second carbonyl group might perturb the excited carbonyl enough so that intersystem crossing is a facile process even in polar solvents. Cohen et al (10) have shown 'Address until August 1972: Chemistry ~epartment, that p-aminobenzophenone is not reduced in tallized from methanol. 4-Hydroxybenzi13 and 4,4'-dihydroxybenzil were prepared from their corresponding benzoins (Aldrich) by oxidation with cupric sulfate, pyridine, and water (13), then cleaving the methoxy group with pyridine hydrochloride at 190-200' (14).…”

Section: Introductionmentioning

confidence: 99%

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The Photolysis of 4-Hydroxybenzil and the Effect of Triethylamine on the Photolysis of Benzil and 4-Hydroxybenzil

Bunbury¹,

Chan²

1972

Can. J. Chem.

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Benzil is photoreduced in neat triethylamine and mixtures of triethylamine and 2-propanol. In neat 2-propanol the principal products are; benzil pinacol, 20%; benzoin benzoate, 19%; benzoin, 18%; and benzoic acid, 12%. When the amine concentration is as low as 0.2 mM the benzil pinacol formation is almost completely suppressed. At amine concentrations higher than 0.36 mM the principal product is benzoin, 80%. At intermediate amine concentrations benzoin benzoate is important. The rate of benzil disappearance reaches a maximum and then declines as either the benzil concentration in triethylamine is increased or the amine concentration in 2-propanol is increased.4-Hydroxybenzil is not photoreduced by 2-propanol. It is reduced by triethylamine. The quantum yield of disappearance is 0.04 at a concentration of 47.8 mM and in solutions containing at least 0.36 M of amine. 4-Hydroxybenzoin is the principal product but at low starting 4-hydroxybenzil concentrations 4,4′-dihydroxybenzil is important. A rate maximum is also observed in this case.4,4′-Dihydroxybenzil is not photoreduced by 2-propanol. It does undergo photoreaction in neat triethylamine but no products were isolated.Triethylamine also appears to suppress biacetyl pinacol formation in the photoreaction of biacetyl with 2-propanol.

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Section: Resultsmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Photolysis of 4-Hydroxybenzil and the Effect of Triethylamine on the Photolysis of Benzil and 4-Hydroxybenzil

Bunbury¹,

Chan²

1972

Can. J. Chem.

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“…Even though several reports are available on the growth aspect of 4-ABP, growth of high quality, inclusion free bulk crystal of 4-ABP is still remaining as a difficult task due to its growth related issues. Moreover, it is difficult to grow 4-ABP single crystal from solution, because it is readily photo-oxidized [5] in solution which results pink colored impurity and it can be easily incorporated into growth sectors of the transparent crystal [5]. For the growth of 4-ABP, several organic solvents such as ethanol, methanol, dimethyl formamide (DMF) were used as the growth medium in the literature [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, it is difficult to grow 4-ABP single crystal from solution, because it is readily photo-oxidized [5] in solution which results pink colored impurity and it can be easily incorporated into growth sectors of the transparent crystal [5]. For the growth of 4-ABP, several organic solvents such as ethanol, methanol, dimethyl formamide (DMF) were used as the growth medium in the literature [5,6]. Pan et al [6] investigated the effect of ethanol, methanol and DMF solvents on the growth of 4-ABP crystals.…”

Section: Introductionmentioning

confidence: 99%

Solubility Studies and Growth of 4-aminobenzophenone Single Crystal: a Potential Organic NLO Material

Natarajan¹,

Usharani²,

Arivanandhan³

et al. 2013

IJSEA

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The solubility and growth aspects of 4-aminobenzophenone (4-ABP) was investigated with an intention to grow bulk and good quality crystal. The solubility of 4-ABP in various organic solvents such as ethyl acetate, ethanol and O-xylene were studied. From the investigation, it was realized that the 4-ABP material has highest solubility in ethyl acetate whereas it has the lowest solubility in pure Oxylene solvent. Single crystals of 4-ABP were grown by solution growth using ethanol as a growth medium which has the moderate solubility when compared to other solvents. The structural and optical properties of the grown 4-ABP samples were studied. The lattice parameters of the 4-ABP were calculated using X-ray diffraction analysis which confirmed the monoclinic structure of the grown material. The optical transmission study showed that the 4-ABP has about 70% of transparency in the visible and near infrared region _______________________________________________________________________________________________________________

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Intermolecular photoreductions of ketones

Scaiano

1973

Journal of Photochemistry

253

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Photoreduction of aminobenzophenones. Effects of solvent on intersystem crossing.

Cited by 10 publications

References 8 publications

The Photolysis of 4-Hydroxybenzil and the Effect of Triethylamine on the Photolysis of Benzil and 4-Hydroxybenzil

The Photolysis of 4-Hydroxybenzil and the Effect of Triethylamine on the Photolysis of Benzil and 4-Hydroxybenzil

Solubility Studies and Growth of 4-aminobenzophenone Single Crystal: a Potential Organic NLO Material

Intermolecular photoreductions of ketones

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