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Pseudo-oxocarbon Anion
In chemistry, the term pseudo-oxocarbon anion is used to refer to a negative ion that is conceptually derived from an oxocarbon anion through replacement of one or more of the basic oxygen atoms by chemically similar elements or functional groups, such as sulfur (S), selenium (Se), or dicyanomethylene (=C(CN)2). Typical examples are the anions 2-(Dicyanomethylene)croconate, croconate violet, and croconate blue, derived from the croconate anion by replacing one, two, or three oxygen atoms by dicyanomethylene groups: These anions retain many of the properties of the parent, including the delocalized bond in the ring and the delocalized charge in the atoms attached to the ring. Alexander J. Fatiadi (1978), ''Synthesis of 1,3-(dicyanomethylene)croconate salts. New bond-delocalized dianion, "Croconate Violet"''. Journal of the American Chemical Society, volume 100 issue 8, pages 2586–2587. Alexander J. Fatiadi (1980), ''Pseudooxocarbons. Synthesis of 1,2,3-tris(dicyanom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth ( botany), the formation of igneous rocks ( geology), how atmospheric ozone is formed and how environmental pollutants are degraded ( ecology), the properties of the soil on the moon ( cosmochemistry), how medications work (pharmacology), and how to collect DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Croconate
Croconic acid or 4,5-dihydroxycyclopentenetrione is a chemical compound with formula or . It has a cyclopentene backbone with two hydroxyl groups adjacent to the double bond and three ketone groups on the remaining carbon atoms. It is sensitive to light, soluble in water and ethanol and forms yellow crystals that decompose at 212 °C. The compound is acidic and loses the protons from the hydroxyl groups (p''K''a1 = and p''K''a2 = at 25 °C). The resulting anions, hydrogencroconate and croconate are also quite stable. The croconate ion, in particular, is aromatic and symmetric, as the double bond and the negative charges become delocalized over the five CO units (with two electrons, Hückel's rule means this is an aromatic configuration). The lithium, sodium and potassium croconates crystallize from water as dihydrates but the orange potassium salt can be dehydrated to form a monohydrate. The croconates of ammonium, rubidium and caesium crystallize i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squarate
Squaric acid, also called quadratic acid because its four carbon atoms approximately form a square, is a diprotic organic acid with the chemical formula C4O2(OH)2. The conjugate base of squaric acid is the hydrogensquarate anion ; and the conjugate base of the hydrogensquarate anion is the divalent squarate anion . This is one of the oxocarbon anions, which consist only of carbon and oxygen. Squaric acid is a reagent for chemical synthesis, used for instance to make photosensitive squaraine dyes and inhibitors of protein tyrosine phosphatases. Chemical properties Squaric acid is a white crystalline powder. The onset of thermal decomposition depends on the different thermodynamic conditions such as heating rates. The structure of squaric acid is not a perfect square, as the carbon–carbon bond lengths are not quite equal. The high acidity with p''K''a = 1.5 for the first proton and p''K''a = 3.4 for the second is attributable to resonance stabilization of the anion. Because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Croconate Blue
Croconate blue or 1,2,3-tris(dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)3(C5O2)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of three oxygen atoms by dicyanomethylene groups =C(−C≡N)2. The term Croconate Blue as a dye name specifically refers to the dipotassium salt . History and synthesis The anion was synthesized and characterized by A. Fatiadi in 1978, together with croconate violet. He obtained the corresponding acid, croconate acid blue by treating croconic acid with malononitrile in water solution at 80–90 °C. Alexander J. Fatiadi (1978), "Synthesis of 1,3-(dicyanomethylene)croconate salts. New bond-delocalized dianion, Croconate Violet". ''Journal of the American Chemical Society'', volume 100 issue 8, pages 2586–2587. Alexander J. Fatiadi (1980), "Pseudooxocarbons. Synthesis of 1,2,3-tris(dicyanomet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anion
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Croconate Violet
Croconate violet or 1,3-bis(dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)2(C5O3)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of two oxygen atoms by dicyanomethylene groups =C(−C≡N)2. Its systematic name is 3,5-bis(dicyanomethylene)-1,2,4-trionate. The term croconate violet as a dye name specifically refers to the dipotassium salt . History and synthesis The anion was synthesized and characterized by Alexander Fatiadi in 1978. He obtained the potassium salt by treating dipotassium croconate with malononitrile in water solution at 80–90 °C. Alexander J. Fatiadi (1978), "Synthesis of 1,3-(dicyanomethylene)croconate salts. New bond-delocalized dianion, "Croconate Violet"". ''Journal of the American Chemical Society'', volume 100 issue 8, pages 2586–2587. The dipotassium salt crystallizes from water as a dihydrate in dee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-(Dicyanomethylene)croconate
2-(Dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)(C5O4)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of one oxygen atom by a dicyanomethylene group =C(−C≡N)2. The anion was synthesized and characterized by A. Fatiadi in 1980, by hydrolysis of croconate violet treated with potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which expl ....Alexander J. Fatiadi (1980), "Pseudooxocarbons. Synthesis of 1,2,3-tris(dicyanomethylene)croconate salts. A new bond-delocalized dianion, croconate blue". ''Journal of Organic Chemistry'' volume 45, pages 1338–1339. It gives an orange solution in water. See also * Croconate violet, 1,3-bis( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
