Ueber chinoïde Derivate des Diphenyls. II

Willstätter, Richard; Kalb, Ludwig

doi:10.1002/cber.190503801226

Cited by 23 publications

(12 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Representative comparisons are provided in the Supporting Information. These observations provide no evidence that diphenoquinone 2 can exist in the red and gold forms reported earlier. , …”

Section: Resultscontrasting

confidence: 81%

“…Other methods of attempted crystallization were thwarted by decomposition of compound 2 . The initial 1905 paper of Willstätter and Kalb reported that diphenoquinone 2 could be obtained in two forms, one red and the other gold, and a similar observation was made later by Detroit and Hart . However, we have not noted a gold polymorph of diphenoquinone 2 in our own work.…”

Section: Resultssupporting

confidence: 79%

“…Parent diphenoquinone 2 was not described until 1905, when Willstätter and Kalb reported it as a reactive compound that could be made by oxidizing 4,4′-dihydroxybiphenyl with PbO 2 . Subsequent researchers have typically resorted to other methods to make the compound, and the original procedure has been reported to be unreliable, to give low yields of product, or to fail altogether. − Diphenoquinone 2 remains elusive, and many aspects of its chemistry have not been explored, such as its structure and the nature of its reactivity.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Diphenoquinones Redux

et al. 2022

View full text Add to dashboard Cite

Benzoquinones can undergo reversible reductions and are attractive candidates for use as active materials in green carbon-based batteries. Related compounds of potential utility include 4,4′-diphenoquinones, which have extended quinonoid structures with two carbonyl groups in different rings. Diphenoquinones are a poorly explored class of compounds, but a wide variety can be synthesized, isolated, crystallized, and fully characterized. Experimental and computational approaches have established that typical 4,4′-diphenoquinones have nearly planar cores in which two cyclohexadienone rings are joined by an unusually long interannular CC bond. Derivatives unsubstituted at the 3,3′,5,5′-positions react readily by hydration, dimerization, and other processes. Association of diphenoquinones in the solid state normally produces chains or sheets held together by multiple C–H···O interactions, giving structures that differ markedly from those of the corresponding 4,4′-dihydroxybiphenyls. Electrochemical studies in solution and in the solid state show that diphenoquinones are reduced rapidly and reversibly at potentials higher than those of analogous benzoquinones. Together, these results help bring diphenoquinones into the mainstream of modern chemistry and provide a foundation for developing redox-active derivatives for use in carbon-based electrochemical devices.

show abstract

Section: Resultscontrasting

confidence: 81%

Section: Resultssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Diphenoquinones Redux

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Willstatter and Kalb first showed that mild oxidation of benzidine produced a green substance and that upon oxidation with silver oxide or lead peroxide a deep yellow quinonoid substance was formed (19,20). Willstatter and Kalb first showed that mild oxidation of benzidine produced a green substance and that upon oxidation with silver oxide or lead peroxide a deep yellow quinonoid substance was formed (19,20).…”

Section: Nature Of Ortho-tolidine Reactionsmentioning

confidence: 99%

The Determination of Free Chlorine

1934

View full text Add to dashboard Cite

A number of reagents have been proposed for determination of free chlorine or chloramine in water. Phelps suggested the use of 0tolidine in acetic acid (1) and Ellms and Hauser devised a method for estimation of chlorine based upon the use of o-tolidine in hydrochloric acid (2). The starch iodide test has been used for some time by certain workers. More recent suggestions are the use of dimethylp-phenylenediamine hydrochloride as a reagent for chlorine (3) and methyl orange for the estimation of chlorine in the absence of chloramine.The chief interfering substances in the accurate determination of chlorine by o-tolidine have been found to be manganese, nitrites and iron (1,5,6,7,8). At an earlier date Boruff and Buswell showed that there was no interference from nitrites and iron under the conditions necessary for making the o-tolidine test for free chlorine (9). But with the present general use of chloramine instead of chlorine longer reaction time must be allowed for the development of full color. Where this long reaction time is used, nitrites and iron, as well as manganese, interfere in the test. Obviously, the o-tolidine reagent is not entirely satisfactory and attempts have been made to adapt the reagent to the purpose by making corrections or eliminating the cause of interference either mechanically or chemically (4).In the o-tolidine test, each of the following would exert an effect: concentration of chlorine, oxidation potential of the chlorine or chloramine, pH and HCl concentration, concentrations of manganese and iron and the degree of oxidation of each, concentration of nitrite, concentration of the reagent and reaction time. With these things in mind work has been carried on in an attempt to find a reagent which would eliminate part of the difficulties experienced with 0tolidine. This investigation has been divided into three parts, involving (I) the application of the principle of oxidation-reduction potentials to the problem (II) nitrite interference in the o-tolidine test and (III) the nature of o-tolidine reactions. 1645

show abstract

“…According to Torrey and Hunter, the coinposition of the product is CGC1402 CGC14(01\ITa)2 The sodium salt was also prepared by a similar method. Oxidation of biphenol with ferricyanide in allraline mediunl gave sodium salt of biphenoquinhydrone as described by IVillstatter and Icalb (5). Biphenol was used in excess to avoid overoxidation.…”

Section: Introductionmentioning

confidence: 99%

The Electron Spin Resonance Absorption Spectra of Semiquinone Ions: Part Iii. Free Radical Salts of Quinhydrones

Matsunaga¹

1960

Can. J. Chem.

View full text Add to dashboard Cite

Electron spin resonance absorption was observed in alkali salts of tetrachloro-p-benzoquinhydrone, p-biphenoq~~inhydrone, and its tetrachloro and tetrabromo derivatives. 'I'he magnitude of g-value was found to be in the order of unsirbstituted < chloro derivative < bromo derivative, and benzoquinhydrone salt < the corresponding p-biphenoquinhydror~e salt. The frequency of C-0 stretching vibration was observed in the range 1525 to 1550 crn-1. Based on these freq~~encies the estimation of the parameters which are necessary for the molecular orbital treatment of serniquinone ions was attempted. A set of no = n+(1/3,-1/2)P and PC" = P were derived. Independently values of no = n+2/3P and PC" = 0 were e s t~~n a t e d ~rsing the hyperline s t r~~c t i~r e of the electron spin resonance spectrum of the n-naphthoserniquinone ion. I N T R O D U C T I O NA number of u~lstable salts of quinhydrones have been described by organic chemists (1). I t is well known that quinhydrones, which have no unpaired electron, dissociate into free radical ions in alkaline solution. Therefore, it seemed to be of interest to study the electronic structure of alkali salts of qui~lhydro~les in the solid state. Electron spin resonance (e.s.r.) absorption has been detected in the quinhydrones adsorbed on barium hydroxide octahydrate (2). The highly colored reaction products of tetrahalogeno-pbenzoquinones with alkali iodides have been examined by the magnetic resonance method and found to be free radical salts (3). Here we wish to present the results of the e.s.r. and the infrared absorption measurements on sodium salts of p-biphenoquinhydrone and its halogeno derivatives. E X P E R I M E N T A LMaterials.-Potassium salt of tetrachloro-p-benzoquinhydrone was prepared by the method of Torrey and Hunter (4). Chloranil was dissolved in cold, dry acetone and treated with crystals of potassiuill iodide. The grass gr'een precipitate was filtered and washed with ether. According to Torrey and Hunter, the coinposition of the product is CGC1402 CGC14(01\ITa)2 The sodium salt was also prepared by a similar method. Oxidation of biphenol with ferricyanide in allraline mediunl gave sodium salt of biphenoquinhydrone as described by IVillstatter and Icalb (5). Biphenol was used in excess to avoid overoxidation. The blue product was quicltly filtered and dried without washing. This salt decomposes quickly in contact with water. Tetrachloro-p-biphenol, \\~hich was obtained by chlorinatio~l of biphenol suspended in acetic acid ( G ) , was dissolved in aqueous solution of sodium hydroxide and oxidized to sodium salt of quinhydrone using ferricyanide. The precipitate changes its color fro111 violet to blue by washing with water. This free radical salt is so stable as to be prepared in the presence of a large excess of the oxidizing reagent. The dark blue salt of tetrabromo-9-biphenoquinhydrone was prepared similarly (7). Bromination of biphenol was carried out as described by Magatti (6).Magnetic measurements.-Electroll spin resonance absorption was lnea...

show abstract

Ueber chinoïde Derivate des Diphenyls. II

Cited by 23 publications

References 15 publications

Diphenoquinones Redux

Diphenoquinones Redux

The Determination of Free Chlorine

The Electron Spin Resonance Absorption Spectra of Semiquinone Ions: Part Iii. Free Radical Salts of Quinhydrones

Contact Info

Product

Resources

About