dicarbonaatit

Dicarbonaatit, in chemische context often referred to as dicarboxylates, are salts or esters derived from dicarboxylic acids that contain two carboxylate groups. In their deprotonated form, they exist as dianions with the general structure [−OOC–R–COO−], where R is a hydrocarbon chain or hydrogen. When only one proton remains, the species is a monoanionic carboxylate, and the neutral parent is the dicarboxylic acid.

Common examples include malonate (propane-1,3-dioate), succinate (butane-1,4-dioate), and the geometric isomers fumarate and maleate (but-2-ene-1,4-dioate). These ligands can appear in different protonation states depending on pH: H2A, HA−, or A2−. The carboxylate groups typically coordinate metals in a bidentate fashion or bridge between multiple metal centers, forming diverse coordination geometries.

In coordination chemistry, dicarbonaatit ligands are valued for their ability to chelate metal ions and to link metal centers, which supports the formation of complexes, clusters, and metal-organic frameworks. Their flexibility, predictable binding modes, and availability from simple precursors make them common building blocks in inorganic synthesis, crystallography studies, and materials science.

Biologically, dicarboxylates such as succinate are intermediates in metabolic pathways, notably the Krebs cycle, linking energy production to other cellular processes. Industrially, they are prepared by neutralizing dicarboxylic acids with bases or by enzymatic methods and serve as versatile starting materials in organic synthesis and polymer chemistry.