Tetrakis(dimethylamido)titanium

Tetrakis(dimethylamino)titanium (TDMAT) is a chemical compound. The compound is generally classified as a metalorganic species, meaning that its properties are strongly influenced by the organic ligands but the compound lacks metal-carbon bonds. It is used in chemical vapor deposition to prepare titanium nitride (TiN) surfaces and in atomic layer deposition as a titanium dioxide precursor. The prefix "tetrakis" refers the presence of four of the same ligand, in this case dimethylamides.

Tetrakis(dimethylamino)titanium
(IV)
Names
Preferred IUPAC name
Tetrakis(dimethylamino)titanium(IV)
Systematic IUPAC name
Dimethyl[tris(dimethylamino)titanio]amine
Other names
Titanium(IV) dimethylamide
Identifiers
3D model (JSmol)
Abbreviations TDMAT
ChemSpider
ECHA InfoCard 100.019.914
EC Number
  • 221-904-3
UN number 2924

3398

Properties
C8H24N4Ti
Molar mass 224.19 g/mol
Appearance yellow liquid
Density 0.947 g/cm³
Boiling point 50 °C (122 °F; 323 K) at 0.05 mmHg
reacts with water
Hazards
R-phrases (outdated) 11-14-34
S-phrases (outdated) 16 - 26 - 36/37/39 - 43 - 45
NFPA 704 (fire diamond)
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineHealth code 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasReactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
3
3
2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Preparation and properties

Tetrakis(dimethylamino)titanium is a conventional Ti(IV) compound in the sense that it is tetrahedral and diamagnetic. Unlike the many alkoxides, the diorganoamides of titanium are monomeric and thus at least somewhat volatile. It is prepared from titanium tetrachloride (which is also tetrahedral, diamagnetic, and volatile) by treatment with lithium dimethylamide:[1]

TiCl4 + 4 LiNMe2 → Ti(NMe2)4 + 4 LiCl

Like many amido complexes, TDMAT is quite sensitive toward water, and its handling requires air-free techniques. The ultimate products of its hydrolysis is titanium dioxide and dimethylamine:

Ti(NMe2)4 + 2 H2O → TiO2 + 4 HNMe2

In a related reaction, the compound undergoes exchange with other amines, evolving dimethylamine.

See also
  • Metalorganic chemical vapor deposition (MOCVD), general process which includes using TDMAT but also uses many other gases to layer other substances.

References
  1. D. C. Bradley and I. M. Thomas, "Part I. Metallo-organic Compounds containing Metal-Nitrogen bonds. Some Dialkylamino-derivatives of Titanium and Zirconium" J. Chem. Soc. 1960, 3857-3861. doi:10.1039/JR9600003857.
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