Homoleptic zirconium amidates: single source precursors for the aerosol-assisted chemical vapour deposition of ZrO₂

Abstract

We report the development of a true single source precursor for the growth of zirconia thin films by aerosol-assisted chemical vapour deposition using an original family of zirconium(iv) amidate derivatives.

Chemical Vapor Deposition of Phase‐Pure Uranium Dioxide Thin Films from Uranium(IV) Amidate Precursors

“…[26] We also observed slow formation of the same products by heating solutions of 7 and 8 to 150 8 8Ci n [D 8 ]toluene over the course of multiple days. These products are consistent with an alkene elimination mechanism (Scheme 3), as reported previously for related homoleptic Zr IV amidates.…”

“…These products are consistent with an alkene elimination mechanism (Scheme 3), as reported previously for related homoleptic Zr IV amidates. [26] We also observed slow formation of the same products by heating solutions of 7 and 8 to 150 8 8Ci n [D 8 ]toluene over the course of multiple days.…”

“…[14,[16][17][18][19][20][21][22] In contrast to the myriad quantity of CVD precursors that have been described for these metals,o nly as mall handful of uranium oxide CVD precursors have ever been reported. [24] We sought to develop aclass of volatile,non-fluorinated precursors with an easily-accessible thermal decomposition pathway to UO 2 , thereby minimizing the heat required to form phase-pure UO 2 films.B ased on previous research in our group [25] and promising results from related transition-metal systems, [26][27][28] we turned to uranium amidate complexes to meet these requirements.A midate ligand substituents can be readily varied to cover aw ide range of steric and electronic properties,e nabling control over the geometry,t hermal stability, volatility,a nd decomposition mechanisms of the resulting metal complexes.U sing new U IV amidate precursors with aw ell-defined decomposition mechanism, we synthesized crystalline,phase-pure UO 2 films via CVD. [23] In am ore recent single-source process,f ilms containing am ixture of uranium oxides were synthesized via thermal CVD from fluorinated uranium heteroarylalkenolate precursors.…”

“…[23] In am ore recent single-source process,f ilms containing am ixture of uranium oxides were synthesized via thermal CVD from fluorinated uranium heteroarylalkenolate precursors. [24] We sought to develop aclass of volatile,non-fluorinated precursors with an easily-accessible thermal decomposition pathway to UO 2 , thereby minimizing the heat required to form phase-pure UO 2 films.B ased on previous research in our group [25] and promising results from related transition-metal systems, [26][27][28] we turned to uranium amidate complexes to meet these requirements.A midate ligand substituents can be readily varied to cover aw ide range of steric and electronic properties,e nabling control over the geometry,t hermal stability, volatility,a nd decomposition mechanisms of the resulting metal complexes.U sing new U IV amidate precursors with aw ell-defined decomposition mechanism, we synthesized crystalline,phase-pure UO 2 films via CVD.Thea mide proligands N-tert-butylisobutyramide (H-(ITA)) (1)a nd N-tert-butylpivalamide (H(TTA)) (2)w ere synthesized according to literature methods [29] and purified by sublimation. Deprotonation of 1 and 2 with KN(SiMe 3 ) 2 in THF generated the corresponding potassium amidates K-(ITA) (3)and K(TTA) (4)inhigh yield.…”

Aerosols: A Sustainable Route to Functional Materials

“…The use of metal alkoxides, amidates and derivatives as precursors has been successfully demonstrated for the synthesis of metal oxide thin films, such as TiO 2 , WO 3 , VO 2 , ZnO, ZrO 2 , and In 2 O 3 . As these metal precursors are soluble in a large range of solvents, there is a greater ability to control the incorporation of dopants.…”