Organometallic access to intermetallic θ-CuE2 (E = Al, Ga) and Cu1-xAlx phases

Mirza Cokoja, Balaji R. Jagirdar, Harish Parala, Alexander Birkner, Roland A. Fischer

Publikation: Beitrag in FachzeitschriftArtikelBegutachtung

15 Zitate (Scopus)

Abstract

In this work, we compare different precursor approaches for the mild decomposition to copper-aluminum and -gallium powder materials in nonaqueous solution. Referring to previous work on the preparation of Cu-Al alloy materials from [(AlCp*)4] and [CpCu(PMe3)], the amine-stabilized metal trihydrides [(Me3N)AlH3] and [(quinuclidine)GaH3] were used as alternative sources for Al and Ga. In a comparative study, [(Me3N)AlH3] and [(AlCp*)4] were treated with the Cu precursors [CpCu(PMe 3)] and [{Cu(mesityl)}5] in mesitylene solution in various molar ratios at 150°C and 3 bar H2 to give metallic precipitates of the composition Cu1-xAlx (x = 0.67, 0.50, 0.31). Whereas the combination [(AlCp*)4] with [{Cu(mesityl)} 5] did not yield an intermetallic phase, all other Cu/Al precursor combinations led to alloyed Cu-Al materials. For x = 0.67, the θ-CuAl 2 phase formed, as shown by X-ray powder diffraction (XRD) and solid-state magic-angle-spinning (MAS)NMR spectroscopic studies. Similarly, the reaction of [{Cu(mesityl)}5] with [(quinuclidine)GaH3] immediately led to the precipitation of a gray powder, without the addition of hydrogen. The powder was identified by means of XRD as θ-CuGa2. At x = 0.50 and below, the reactions were less phase selective depending on the precursor combination. [CpCu(PMe3)] combined with both Al precursors afforded a mixture of several Cu-Al phases, whereas [{Cu(mesityl)}5] was treated with [(Me3N)AlH3] to yield a material whose X-ray signature was assigned to the monoclinic Cu0.51Al 0.49 phase. The γ-Cu9Al4 phase could not be obtained from [CpCu(PMe3)]; instead, solid solutions of α-Cu were obtained. The treatment of [{Cu(mesityl)}5] with [(Me 3N)AlH3] in the Cu/Al molar ratio of 9:4 (x = 0.31) gave a gray powder, which could be identified by XRD as γ-Cu9Al 4.

OriginalspracheEnglisch
Seiten (von - bis)3330-3339
Seitenumfang10
FachzeitschriftEuropean Journal of Inorganic Chemistry
Ausgabenummer21
DOIs
PublikationsstatusVeröffentlicht - Juli 2008
Extern publiziertJa

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