Acid salts of citric acid can be prepared by careful adjustment of the pH before crystallizing the compound, for example, sodium citrate.

The citrate ion forms complexes with metallic cations. The stability constants for the formation of these complexes are quite large because of the chelate effect. Consequently, it forms complexes even with alkali metal cations. However, when a chelate complex is formed using all three carboxylate groups, the chelate rings have 7 and 8 members, which are generally less stable thermodynamically than smaller chelate rings. In consequence, the hydroxyl group can be deprotonated, forming part of a more stable 5-membered ring, as in ammonium ferric citrate.

Citric acid can be esterified at one or more of its three carboxylic acid groups to form any of a variety of mono-, di-, tri-, and mixed esters.

Chelate: Geology

In earth science, chemical weathering is attributed to organic chelating agents (e.g., peptides and sugars) that extract metal ions from minerals and rocks. Most metal complexes in the environment and in nature are bound in some form of chelate ring (e.g., with a humic acid or a protein). Thus, metal chelates are relevant to the mobilization of metals in the soil, the uptake and the accumulation of metals into plants and microorganisms. Selective chelation of heavy metals is relevant to bioremediation (e.g., removal of 137Cs from radioactive waste).

chloride choline salt acid synthesis, choline can be prepared by methylation of dimethylethanolamine with methyl chloride.

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Ligands
Chelate
Chelants
Chelators
Chelating Agents
Sequestering Agents
Reducing Agents
Peptides
Glycine / Sugars
Glutamate
Protease
Ions
Amino Acids
EDTA
Dithiothreitol
Ethylenediaminetetraacetic
Bleomycin
Hydrophilic
ATP-Binding Cassette Transporter
Thiamine Tetrahydrofurfuryl Disulfide (TTFD)
Bifidobacterium longum
GABA
BDNF (Abrineurin)
DHA (Carboxylic Acid)
Lithium
Choline
Progesterone
Acetylcholine
Corticosteroids
Neurosteroid

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https://en.m.wikipedia.org/wiki/Citric_acid

https://en.m.wikipedia.org/wiki/Chelation

https://en.m.wikipedia.org/wiki/Chelation_therapy

https://en.m.wikipedia.org/wiki/Ethylenediaminetetraacetic_acid

https://en.m.wikipedia.org/wiki/Glutamate_(neurotransmitter)

https://en.m.wikipedia.org/wiki/Protease

Glutamates in Magnesium Chelates (Danger)

https://drcarolyndean.com/2011/01/glutamates-in-magnesium-chelates/

Balancing Glutamate and GABA for Anxiety and Depression

https://nutritiongenome.com/glutamates-role-in-depression-and-anxiety/