Cyclic polyhydroxy ketones. I. Oxidation products of hexahydroxybenzene (benzenehexol)

Fatiadi, Alexander J.; Isbell, Horace S.; Sager, W. F.

doi:10.6028/jres.067a.015

Cited by 49 publications

(26 citation statements)

References 7 publications

(7 reference statements)

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“…Rhodizonic acid was synthesized from glyoxal in two steps according to the method of Fatiadi. 24 RA was thermally evaporated onto the surfaces held at room temperature in a home-built Knudsen cell evaporator.…”

Section: Experimental Methodsmentioning

confidence: 99%

Rhodizonic Acid on Noble Metals: Surface Reactivity and Coordination Chemistry

Kunkel

Hooper

Simpson

et al. 2013

J. Phys. Chem. Lett.

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A study of the two-dimensional crystallization of rhodizonic acid on the crystalline surfaces of gold and copper is presented. Rhodizonic acid, a cyclic oxocarbon related to the ferroelectric croconic acid and the antiferroelectric squaric acid, has not been synthesized in bulk crystalline form yet. Capitalizing on surface-assisted molecular selfassembly, a two-dimensional analogue to the well-known solution-based coordination chemistry, two-dimensional structures of rhodizonic acid were stabilized under ultrahigh vacuum on Au(111) and Cu(111) surfaces. Scanning tunneling microscopy, coupled with first-principles calculations, reveals that on the less reactive Au surface, extended twodimensional islands of rhodizonic acid are formed, in which the molecules interact via hydrogen bonding and dispersion forces. However, the rhodizonic acid deprotonates into rhodizonate on Cu substrates upon annealing, forming magic clusters and metal−organic coordination networks with substrate adatoms. The networks show a 2:1 distribution of rhodizonate coordinated with 3 and 6 Cu atoms, respectively. The stabilization of crystalline structures of rhodizonic acid, structures not reported before, and their transition into metal−organic networks demonstrate the potential of surface chemistry to synthesize new and potential useful organic nanomaterials.

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Section: Experimental Methodsmentioning

confidence: 99%

Rhodizonic Acid on Noble Metals: Surface Reactivity and Coordination Chemistry

Kunkel

Hooper

Simpson

et al. 2013

J. Phys. Chem. Lett.

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“…Croconic acid and its potassium salt were prepared according to the procedure described by Fatiadi et al (17).…”

Section: Methodsmentioning

confidence: 99%

A photo-oxidation of croconic acid into oxalic acid

Fabre¹,

Castan²,

Deguenon³

et al. 1995

Can. J. Chem.

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Croconic acid, H2C5O5. is readily oxidized. This may be attested by decolorization of the solutions and by observation of oxalic acid complexes. The oxidation products are identified by I3C NMR spectroscopy as oxalic and mesoxalic acids, and experimental conditions are specified. The oxidation process requires dioxygen and photons. In parallel, the electrochemical oxidation of croconic acid is studied in aqueous media and in acetonitrile. A potential-pH diagram is drawn. 4,5-Dihydroxycyclopentenetrione 1, commonly known as "croconic" acid, H2C505, and the croconate anion [C,O,]~-have received considerable attention from both a theoretical and an experimental point of view (1-6). Croconate, like squarate or rhodizonate ions, is a member of the oxocarbon ring system, [cn0,12-, a new class of aromatic substances with planar structure containing only carbon and oxygen atoms. Both croconic and squaric acids are strong acids in aqueous solution, having pK,, values of 0.80 (7) and 0.54 (8), respectively.During the course of our investigations concerning transition metal complexes of croconic acid we attempted to prepare a manganese croconate complex. In the presence of croconic acid, 2,2'-bipyridine, and Mn(I1) salt, the complex [Mn(CloHsN2)(C204)], was unexpectedly obtained, and was structurally identified (9). This synthesis requires the oxidation of croconic acid into oxalic acid.Oxidation of croconic acid and of other polyketo compounds by molybdenum(V1) in acidic media has already been described by ; a transient 111 complex between Mo(V1) and the ionized acid was shown. 0xalic and mesoxalic acids were identified among the oxida-

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“…Croconic acid (Z), croconic acid sodium salt and diethyl croconate (2c). The preparation of croconic acid (Z), its sodium salt (22-) and of diethyl croconate (2c) followed the reaction schemes as horked out by Sager et al [18] and Malachowsky & Prebendowsky [19]. The conversion of croconic acid barium salt to the free acid (2) has been changed with respect to Sager's original procedure.…”

Section: Experimental Partmentioning

confidence: 99%

“…Dimethyl syuarate (3c) was obtained according to the procedure given by Cohen & Cohen [20]. The polyhydrated species, 'octahydrate' 5, leuconic acid (pentahydrate) (6) and octahydroxycyclobutane (7) were obtained by nitric acid oxydation of tetrahydroxy-p-benzoquinone (9), croconic acid (2) and squaric acid (3) respectively [18].…”

Section: Experimental Partmentioning

confidence: 99%

¹³C‐NMR. Spectra, Structure and Reactivity of Cyclic Oxocarbons

Städeli

Hollenstein

Philipsborn

1977

Helvetica Chimica Acta

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SummaryThe structures of cyclic polyketones, their hydrates and reduction products were studied in different solvents by 13C-NMR. spectroscopy. In dimethylsulfoxide solution rhodizonic acid (l), croconic acid (2) and squaric acid (3) exhibit signal averaging. In anhydrous tetrahydrofuran 1 and 2 could be observed as non-dynamic species. The spontaneous reactions of dodecahydroxycyclohexane (5) and decahydroxycyclopentane ('leuconic acid') (6) and the sequence of formation of ring-contracted products were investigated. Key intermediates could be clearly identified which support the mechanism proposed earlier involving a benzylic acid type rearrangement followed by decarboxylation and subsequent redox reactions.

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Cyclic polyhydroxy ketones. I. Oxidation products of hexahydroxybenzene (benzenehexol)

Cited by 49 publications

References 7 publications

Rhodizonic Acid on Noble Metals: Surface Reactivity and Coordination Chemistry

Rhodizonic Acid on Noble Metals: Surface Reactivity and Coordination Chemistry

A photo-oxidation of croconic acid into oxalic acid

¹³C‐NMR. Spectra, Structure and Reactivity of Cyclic Oxocarbons

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Cyclic polyhydroxy ketones. I. Oxidation products of hexahydroxybenzene (benzenehexol)

Cited by 49 publications

References 7 publications

Rhodizonic Acid on Noble Metals: Surface Reactivity and Coordination Chemistry

Rhodizonic Acid on Noble Metals: Surface Reactivity and Coordination Chemistry

A photo-oxidation of croconic acid into oxalic acid

13C‐NMR. Spectra, Structure and Reactivity of Cyclic Oxocarbons

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¹³C‐NMR. Spectra, Structure and Reactivity of Cyclic Oxocarbons