1,3-Bis(dicyanomethylene)squarate
Encyclopedia
1,3-Bissquarate is a divalent
anion with chemical formula
or ((N≡C-)2C=)2(C4O2)2−. It is one of the pseudo-oxocarbon anion
s, as it can be described as a derivative of the squarate
oxocarbon anion
through the replacement of two opposite oxygen
atoms by dicyanomethylene group
s =C(-C≡N)2.
The anion can be obtained by reacting squaric acid
with aniline
to obtain the diester 1,3-dianiline squarate (a yellow solid) and treating the latter with malononitrile
(N≡C-)2CH2 and sodium ethanolate to give the tetrahydrated
disodium salt 2··4H2O, an orange water-soluble solid. The hydrated salt loses the water below 100°C but the resulting anhydrous salt is stable up to 400°C. Reaction of the sodium salt with salts of other cations in ethanol affords the following salts:
Nuclear magnetic resonance
shows that the aromatic character of the squarate core is retained.
Valence (chemistry)
In chemistry, valence, also known as valency or valence number, is a measure of the number of bonds formed by an atom of a given element. "Valence" can be defined as the number of valence bonds...
anion with chemical formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
or ((N≡C-)2C=)2(C4O2)2−. It is one of the pseudo-oxocarbon anion
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 , selenium , or dicyanomethylene...
s, as it can be described as a derivative of the squarate
Squaric acid
Squaric acid, also called quadratic acid, because its four carbon atoms approximately form a square, is an organic compound with chemical formula 424....
oxocarbon anion
Oxocarbon anion
In chemistry, an oxocarbon anion is a negative ion consisting solely of carbon and oxygen atoms, and therefore having the general formula CxOyn− for some integers x, y, and n....
through the replacement of two opposite oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
atoms by dicyanomethylene group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
s =C(-C≡N)2.
The anion can be obtained by reacting squaric acid
Squaric acid
Squaric acid, also called quadratic acid, because its four carbon atoms approximately form a square, is an organic compound with chemical formula 424....
with aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...
to obtain the diester 1,3-dianiline squarate (a yellow solid) and treating the latter with malononitrile
Malononitrile
Malononitrile, also propanedinitrile, is a nitrile, with formula CH22. Malononitrile is relatively acidic, with an pKa of 11 in water...
(N≡C-)2CH2 and sodium ethanolate to give the tetrahydrated
Hydrate
Hydrate is a term used in inorganic chemistry and organic chemistry to indicate that a substance contains water. The chemical state of the water varies widely between hydrates, some of which were so labeled before their chemical structure was understood....
disodium salt 2··4H2O, an orange water-soluble solid. The hydrated salt loses the water below 100°C but the resulting anhydrous salt is stable up to 400°C. Reaction of the sodium salt with salts of other cations in ethanol affords the following salts:
- dipotassiumPotassiumPotassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
sodium chloride 2K+·Na+···0.5CH3CN, orange - rubidiumRubidiumRubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group. Its atomic mass is 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1, such as very rapid...
sodium chloride 7Rb+·Na+·2·3·, orange, loses 1 ethanol at 96°C, stable to 361°C - magnesiumMagnesiumMagnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
disodium nitrate, ·2Na+··6H2O·, orange, loses 1 ethanol and 6 H2O at 78°C, stable to 482°C - calciumCalciumCalcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
, ··6H2O, purple, dehydrates at 63–102°C, stable to 468°C - bariumBariumBarium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with...
, ··4H2O, orange, dehydrates at 71–96°C, stable to 457°C - tetra-n-butylammonium sodium, 24N+·2Na+·2·2·, orange, loses 1 ethanol and 2 TBA at 111°C, stable to 238°C
Nuclear magnetic resonance
Nuclear magnetic resonance
Nuclear magnetic resonance is a physical phenomenon in which magnetic nuclei in a magnetic field absorb and re-emit electromagnetic radiation...
shows that the aromatic character of the squarate core is retained.