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Ligações hidrogênio fortes em ácidos dicarboxílicos e diaminas aromáticas

2000; Brazilian Chemical Society; Volume: 23; Issue: 6 Linguagem: Inglês

10.1590/s0100-40422000000600015

1678-7064

José Augusto R. Rodrigues,

Chemical Reaction Mechanisms

AROMATICS DIAMINES.A very short-strong hydrogen bond ( 20kcal/mol) is found in the monoanion of certain dicarboxylic acids derived from maleic and dialkylmalonic acids.Certain aromatic diamines that are known as proton sponge have exceptionally high basicity (pK a ) and are only monoprotonated with strong acids like percloric acid.The closed proximity between the two basic centers provokes a strong steric interaction that is relieved upon protonation.Similar effects are found in dicarboxylic acids (hydrogen maleate and hydrogen dialkylmalonates) that present a very short distance between the two oxygens and a short-strong hydrogen bond.