1,4-Phenylenedimethanamine dihydroiodide
[CAS# 2304829-65-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Amine salt (ammonium salt)
• Name: 1,4-Phenylenedimethanamine dihydroiodide
• Synonyms: [4-(aminomethyl)phenyl]methanamine dihydroiodide
• Molecular Formula: C₈H₁₄I₂N₂
• Molecular Weight: 392.02
• CAS Registry Number: 2304829-65-8
• SMILES: C1=CC(=CC=C1CN)CN.I.I

Discovory and Applicatios

1,4-Phenylenedimethanamine dihydroiodide is the dihydroiodide salt of 1,4-phenylenedimethanamine, also known as p-xylylenediamine. This compound consists of a benzene ring substituted at the para positions with two aminomethyl groups (–CH₂NH₂). When treated with hydroiodic acid, each of the amino groups is protonated, resulting in the formation of a stable crystalline salt with two equivalents of iodide counterions.

The preparation of the hydroiodide salt of p-xylylenediamine fits into a long-standing practice in organic and medicinal chemistry of converting amines into their corresponding hydrohalide salts to improve stability, solubility, and handling. The free base, p-xylylenediamine, is a colorless to pale yellow liquid that is reactive, strongly basic, and prone to oxidation, whereas the dihydroiodide salt is more stable and can be readily crystallized, stored, and transported.

The discovery of p-xylylenediamine itself dates back to the early 20th century, during investigations into aromatic diamines as potential monomers and intermediates for polymers, resins, and dyes. Conversion to the hydroiodide salt would have been a straightforward process for characterization and purification, allowing researchers to study its chemical properties under controlled conditions.

In terms of applications, p-xylylenediamine and its salts are useful as intermediates in the synthesis of polymers and crosslinking agents. The diamine structure enables reactions with diacids, diisocyanates, or other multifunctional reagents to form polyamides, polyureas, and epoxy curing agents. The hydroiodide salt provides a stable precursor that can be converted back into the free amine in situ during synthetic processes.

Another application lies in the study of structure–activity relationships of aromatic diamines in both chemical and biological contexts. While p-xylylenediamine is not a natural metabolite, its structural resemblance to biologically relevant diamines and polyamines makes it of interest in biochemical research. The hydroiodide form, with its increased solubility in aqueous systems, has been used in controlled studies of amine–receptor interactions and enzyme activity involving aromatic amine substrates.

Additionally, aromatic diamines such as p-xylylenediamine have been studied for their role as ligands in coordination chemistry. The presence of two amino groups in fixed positions on an aromatic ring provides a rigid binding framework for metal ions. The hydroiodide salt serves as a convenient form for storage and preparation of such ligands, with the iodide ions acting solely as counterions without interfering significantly in coordination processes once the free base is regenerated.

In summary, 1,4-phenylenedimethanamine dihydroiodide is a stable crystalline salt form of p-xylylenediamine, prepared to improve handling and solubility relative to the free base. It has been applied primarily as a precursor in polymer chemistry, a tool in biochemical investigations of amine interactions, and a starting material in coordination studies. Its preparation and use reflect the general utility of hydrohalide salts of diamines in both fundamental and applied chemistry.