Dimethylammonium iodide
[CAS# 51066-74-1]

Identification

• Classification: Chemical reagent >> Organic reagent >> Amine salt (ammonium salt)
• Name: Dimethylammonium iodide
• Synonyms: N-methylmethanamine hydroiodide
• Molecular Formula: C₂H₈IN
• Molecular Weight: 173.00
• CAS Registry Number: 51066-74-1
• EC Number: 256-945-6
• SMILES: CNC.I

Properties

• Melting point: 153.85 °C (Expl.)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovery and Applications

Dimethylammonium iodide is a simple organic salt formed by the protonation of dimethylamine with hydroiodic acid. The resulting compound consists of a dimethylammonium cation (–NH(CH₃)₂⁺) and an iodide anion. This salt is typically obtained as a crystalline solid that is stable under ambient conditions, readily soluble in water, and serves as a convenient source of the dimethylammonium cation in various chemical applications.

The development of dimethylammonium salts, including the iodide, stems from the broader history of simple ammonium salts in organic and inorganic chemistry. Ammonium salts have long been employed for their stability, ease of handling, and utility as reagents or intermediates. Dimethylammonium iodide, in particular, provides a non-volatile, easily measured form of dimethylamine that can be used in aqueous or polar organic media.

A primary application of dimethylammonium iodide is in the field of hybrid perovskite materials, especially in photovoltaic devices. Organic–inorganic halide perovskites are typically described by the formula ABX₃, where A is a cation, B is a metal cation (commonly Pb²⁺), and X is a halide anion. Dimethylammonium can act as the A-site cation in two-dimensional or mixed-dimensional perovskites, stabilizing the lattice and influencing the optoelectronic properties of the material. Compared to methylammonium, the dimethylammonium cation is bulkier, which can lead to layered structures with enhanced moisture resistance and tunable bandgaps. These characteristics make it useful in designing perovskite solar cells with improved environmental stability and potentially reduced ion migration.

In addition to materials science, dimethylammonium iodide is employed as a reagent in organic synthesis. The salt can serve as a source of the dimethylammonium cation in phase-transfer catalysis or in reactions requiring controlled introduction of an amine group. Its crystalline, non-volatile form makes it easier to handle than the free amine, and the iodide counterion can participate in substitution reactions or facilitate halide exchange processes.

The iodide salt also finds utility in research on ionic liquids and deep eutectic solvents, where small ammonium cations and halide anions are combined to generate liquids with low melting points, high ionic conductivity, and strong solvation properties. Dimethylammonium iodide, due to its small size and solubility, can be incorporated into such systems to modulate viscosity, hydrogen-bonding interactions, and electrochemical properties.

Overall, dimethylammonium iodide is a versatile organic salt whose discovery and use are tied to the broader study of ammonium salts in chemistry. Its main applications lie in perovskite solar cell research, where it stabilizes and modifies hybrid structures, as well as in synthetic and ionic liquid chemistry. Its stability, solubility, and ease of handling make it a valuable reagent for both laboratory studies and advanced materials development.

References

2021. Healing the defects in CsPbI3 solar cells by CsPbBr3 quantum dots. Nano Research.
DOI: 10.1007/s12274-021-3737-9

2023. Recent progress in the development of high-efficiency inverted perovskite solar cells. NPG Asia Materials.
DOI: 10.1038/s41427-023-00474-z

2024. Efficient and stable perovskite solar cells using low-cost dimethylammonium iodide additive. Journal of Materials Chemistry A.
DOI: 10.1039/D4TA01234B