Application of chemically induced dynamic nuclear polarization to a kinetic study of phenyl radical reactions

Kasukhin, L. F.; Ponomarchuk, M. P.; Бучаченко, А. Л.

doi:10.1016/0301-0104(74)80084-4

Cited by 16 publications

(5 citation statements)

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“…Subsequently, there are two different possible interactions between substrates and excited triplet Ru. Path I is an oxidative quenching process, in which diazonium salt 1 obtains an electron from 3 *[Ru(bpy) 2 (bpy .− )Cl 2 ] and generates the phenyl diazonium radical A (lifetime about 10 −7 s) 19. Then, radical A couples with the thiosulfate electrophilic radical B , which originated from 2 .…”

Section: Resultsmentioning

confidence: 99%

“…Not only substitut-ed benzylt hiosulfates (15)(16), but also alkyl ones with diverse functional groups (17-18)c ould afford the desired products. In addition, the sp 2 -thiosulfates (19)(20)c ould also be utilized to synthesize diphenyl sulfide structures. Af ree combination of both parts was investigated as well (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31).…”

Section: Synthetic Compatibilityinvestigationmentioning

confidence: 99%

“…Path Ii sa no xidativeq uenching process, in which diazonium salt 1 obtains an electron from 3 *[Ru(bpy) 2 (bpyC À À )Cl 2 ]a nd generates the phenyl diazonium radical A (lifetime about 10 À7 s). [19] Then, radical A couples with the thiosulfate electrophilic radical B,w hich originatedf rom 2.O nt he other hand, path II is ar eductiveq uenching process. Benzylt hiosulfate could deliver an electron to the excited tripletR u, which generates benzylt hiosulfate cationic radical B and Ru + .T hen, Ru + is oxidized by the phenyld iazonium salt and regenerates the Ru 2 + species.…”

Section: Mechanistic Studymentioning

confidence: 99%

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Mechanistic Study of a Photocatalyzed CS Bond Formation Involving Alkyl/Aryl Thiosulfate

Xie

Jiang

2015

Chemistry A European J

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This study presents thioether construction involving alkyl/aryl thiosulfates and diazonium salt catalyzed by visible-light-excited [Ru(bpy)3 Cl2 ] at room temperature in 44-86 % yield. Electron paramagnetic resonance studies found that thiosulfate radical formation was promoted by K2 CO3 . Conversely, radicals generated from BnSH or BnSSBn (Bn=benzyl) were clearly suppressed, demonstrating the special property of thiosulfate in this system. Transient absorption spectra confirmed the electron-transfer process between [Ru(bpy)3 Cl2 ] and 4-MeO-phenyl diazonium salt, which occurred with a rate constant of 1.69×10(9) M(-1) s(-1) . The corresponding radical trapping product was confirmed by X-ray diffraction. The full reaction mechanism was determined together with emission quenching data. Furthermore, this system efficiently avoided the over-oxidation of sulfide caused by H2 O in the photoexcited system containing Ru(2+) . Both aryl and heteroaryl diazonium salts with various electronic properties were investigated for synthetic compatibility. Both alkyl- and aryl-substituted thiosulfates could be used as substrates. Notably, pharmaceutical derivatives afforded late-stage sulfuration smoothly under mild conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Synthetic Compatibilityinvestigationmentioning

confidence: 99%

Section: Mechanistic Studymentioning

confidence: 99%

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Mechanistic Study of a Photocatalyzed CS Bond Formation Involving Alkyl/Aryl Thiosulfate

Xie

Jiang

2015

Chemistry A European J

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“…The transfer of an electron from C6H5N=Ntd (1)+ results in the reduction of (1)+ to (1) and the oxidation of the anionic ligand to a neutral radical. The displacement of C6H5N=N' is essentially irreversible, because this radical is extremely unstable, with a mean life of only 10-7 s (Kasukhin et al, 1974). The transfer of an electron in the reverse direction, from an iron porphyrin to its ligand, occurs in the formation of ferrihaemogloin (Hb+) from oxyhaemoglobin (HbO2) in the presence of an anionic ligand of Hb+ (Wallace et al, 1982):…”

Section: Discussionmentioning

confidence: 99%

Formation of aryl and aryldiazenyl complexes in reactions of arylhydrazines and aryldiazenes with a synthetic model compound of haemoprotein

Kinuta¹,

Matteson²,

Itano³

1986

Biochemical Journal

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The anaerobic reaction of chelated protohaemin, a synthetic model compound of ferrihaemoglobin, with phenyldiazene produced a compound with the visible-absorption spectrum of a ferrihaemochrome. The compound reacted with CN-, which is a ligand of both ferric and ferrous porphyrins, to produce the complex of the synthetic ferrihaemoglobin with CN-. Though the spectrum of the compound formed by the addition of phenyldiazene to chelated protohaemin is characteristic of a ferric porphyrin complex, this compound reacted with both toluene-p-sulphonylmethyl isocyanide and CO, which are strong ligands of ferrous porphyrins, to produce the corresponding ferrous complexes. These ligand-binding reactions indicated that the complex of chelated protohaem with phenyldiazene can behave either as a complex of a ferric porphyrin with phenyldiazenyl anion (C6H5N = N-) or a complex of a ferrous porphyrin with phenyldiazenyl radical (C6H5N = N.). Para substituents on phenyldiazene were without effect on the formation of 4-substituted phenyldiazenyl complexes with chelated protohaem. Ortho substituents resulted in less-stable complexes. The phenyl complex of chelated protohaem was prepared by the aerobic reaction of phenylhydrazine with chelated protohaemin, and its structure was confirmed by its n.m.r. spectrum. The ligand-binding properties, n.m.r. spectrum and absorption spectrum of this complex differed from those of the phenyldiazenyl complex. The phenyl complex also was produced when the phenyldiazenyl complex was exposed to O2.

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“…Phenyldiazene (C6H5N:NH) reacts rapidly with oxygen to become phenyldiazenyl radical (21), which immediately decomposes to phenyl radical and N2 (22). C6H5N:NH + 02 -_ C6H5N:N' + H + 02- [2] C6H5N:N---C6H5-+ N2 [3] Eqs.…”

Section: Discussionmentioning

confidence: 99%

beta-meso-Phenylbiliverdin IX alpha and N-phenylprotoporphyrin IX, products of the reaction of phenylhydrazine with oxyhemoproteins.

Saito¹,

Itano²

1981

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

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Oxyhemoglobin and oxymyoglobin were allowed to react aerobically with phenylhydrazine and p-tolylhydrazine. The chloroform extract of each reaction mixture, after treatment with H2SOdmethanol, yielded a blue pigment and a.green pigment, which were identified by electronic absorption, mass, and proton NMR spectroscopy as the dimethyl esters of -mao-arylbiliverdin IXa and N-arylprotoporphyrin IX, respectively. NPhenyiprotoporphyrin IX dimethyl ester formed complexes, with Zn2+, Cd'+, and Hg'+ but not with other cations. The proton NMR spectrum of the zinc complex suggested binding of the phenyl group to one ofthe two pyrrole rings ofprotoporphyrin IX with a propionic acid substitutent. The effectiveness of phenylhydrazine as an inducer of Heinz body formation may be due to destabilization of the hemoglobin. molecule by the replacement of heme with phenyl adducts of biliverdin and protoporphyrin.The green hemoglobin produced in the reaction ofhemoglobin with phenylhydrazine was found by Kiese and Seipelt (1) to differ from verdoglobins produced by other reagents. Lemberg and Legge (2) showed that biliverdin production was increased in the erythrocytes ofrabbits treated with phenylhydrazine, and they concluded that this in vivo result of phenylhydrazine activity corresponded to the in vitro formation ofbiliverdin in the coupled oxidation ofhemoglobin and ascorbic acid. Beaven and White (3), on the other hand, did not obtain biliverdin in the in vitro reaction of phenylhydrazine with oxyhemoglobin; instead they isolated a green pigment with an absorption band in the Soret region suggestive of an intact porphyrin ring.Studies from this laboratory indicated that substituents on the benzene ring affected the hemolytic activity of substituted phenylhydrazine and the binding ofsubstituted phenyldiazenes to methemoglobin in parallel fashion (4). Subsequent studies showed, however, that the hemolytic activity of ring-substituted nitrosobenzenes was not related to their affinities as ligands of deoxyhemoglobin (5).A two-electron transfer to oxyhemoglobin was suggested as the initial step in the degradation ofheme mediated by ascorbic acid (6), and the same transfer was postulated in the reaction of phenylhydrazine with oxyhemoglobin (4). Although the processes may be initiated in the same way, different reported products, biliverdin with ascorbic acid (2) and an intact porphyrin with phenyihydrazine (3), indicate that subsequent steps are different. We therefore undertook to isolate and characterize the products of heme degradation when hemoglobin is treated with arylhydrazines, and we found two types of compounds: one is a biliverdin IXa derivative with an aryl group on a meso carbon, and the other is a protoporphyrin IX derivative with an aryl group on a pyrrole nitrogen.EXPERIMENTAL PROCEDURES Materials and Methods. To a solution of metmyoglobin (5 g, type III from horse heart, Sigma) in potassium phosphate buffer (pH 7.4, 0.01 M, 200 ml), a 50-fold excess of powdered Na2S204 was added under N2. This mixture wa...

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Application of chemically induced dynamic nuclear polarization to a kinetic study of phenyl radical reactions

Cited by 16 publications

References 9 publications

Mechanistic Study of a Photocatalyzed CS Bond Formation Involving Alkyl/Aryl Thiosulfate

Mechanistic Study of a Photocatalyzed CS Bond Formation Involving Alkyl/Aryl Thiosulfate

Formation of aryl and aryldiazenyl complexes in reactions of arylhydrazines and aryldiazenes with a synthetic model compound of haemoprotein

beta-meso-Phenylbiliverdin IX alpha and N-phenylprotoporphyrin IX, products of the reaction of phenylhydrazine with oxyhemoproteins.

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