1,2-Bis(dicyanomethylene)squarate is a
divalent
anion with
chemical formula C
10N
4O2−
2 or ((N≡C−)2C=)2(C4O2)2−. It is one of the
pseudo-oxocarbon anions, as it can be described as a derivative of the
squarate
oxocarbon anion C
4O2−
4 through the replacement of two adjacent
oxygen atoms by
dicyanomethylene
groups =C(−C≡N)2.
The anion can be obtained by reacting
squaric acid with
n-butanol to obtain the
diester
1,2-dibutyl squarate (an oily orange liquid) and treating the latter with metallic
sodium and
malononitrile (N≡C−)2CH2 to give the
trihydrated disodium salt 2Na+·C
10N
4O2−
2·3H2O, a yellow water-soluble solid. The hydrated salt loses the water below 100 °C, but the resulting anhydrous salt is stable up to 400 °C.
[1] Reaction of the sodium salt with the
chlorides of other
cations in ethanol affords the following salts:
[1]
Nuclear magnetic resonance shows that the aromatic character of the squarate core is retained. [1]
1,2-Bis(dicyanomethylene)squarate is a
divalent
anion with
chemical formula C
10N
4O2−
2 or ((N≡C−)2C=)2(C4O2)2−. It is one of the
pseudo-oxocarbon anions, as it can be described as a derivative of the
squarate
oxocarbon anion C
4O2−
4 through the replacement of two adjacent
oxygen atoms by
dicyanomethylene
groups =C(−C≡N)2.
The anion can be obtained by reacting
squaric acid with
n-butanol to obtain the
diester
1,2-dibutyl squarate (an oily orange liquid) and treating the latter with metallic
sodium and
malononitrile (N≡C−)2CH2 to give the
trihydrated disodium salt 2Na+·C
10N
4O2−
2·3H2O, a yellow water-soluble solid. The hydrated salt loses the water below 100 °C, but the resulting anhydrous salt is stable up to 400 °C.
[1] Reaction of the sodium salt with the
chlorides of other
cations in ethanol affords the following salts:
[1]
Nuclear magnetic resonance shows that the aromatic character of the squarate core is retained. [1]