Cyclic Trimeric Hydroxy, Amido, Phosphido, and Arsenido Derivatives of Aluminum and Gallium. X-ray Structures of [t-Bu2Ga(µ-OH)]3 and [t-Bu2Ga(µ-NH2)]3

David A. Atwood, Alan H. Cowley, Paul R. Harris, Richard A. Jones, Stefan U. Koschmieder, Christine M. Nunn, Jerry L. Atwood, Simon G. Bott

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61 Scopus citations


Reaction of t-Bu3Al with PH3 or AsH3 produces cyclic trimeric complexes of formula [t-Bu2Al(µ-EH2)]3 (E = P (1), As (2), which were identified by their IR, NMR, and mass spectra. From infrared data the ∠H-P-H and ∠H-As-H angles are calculated to be 97 (3) and 105 (3)°, respectively. The adduct t-Bu3GaNH3 (3) may be isolated from mixtures of t-Bu3Ga and NH3 at room temperature. Heating 3 to 160 °C results in the formation of [t-Bu2Ga(µ-NH2)]3 (4), whose cyclic trimeric structure was confirmed in the solid state by X-ray crystallography. The analogous µ-ND2 complex 5 can be prepared by substituting ND3 for NH3. Reaction of t-Bu3Ga with H2O in pentane solution at 25 °C gives the cyclic trimer [t-Bu2Ga(µ-OH)]3 (6) in 90% yield. The deuterium-labeled compound [t-Bu2Ga(µ-OD)]3 (7) may be prepared in a similar fashion using D2O. Compound 6 is also formed by the hydrolysis of [t-Bu2Ga(µ-PH2)]3, [t-Bu2Ga(µ-AsH2)]3, and [t-Bu2Ga(µ-As(t-Bu)H)]3. The cyclic trimeric structure of 6 was confirmed by X-ray crystallography, which showed a planar Ga3O3 ring with t-Bu groups extending above and below the plane. Crystal data for 4: C24H60N3Ga3; Mn = 600.03; rhombohedral space group R3̅c; a = 10.443 (2) Å; c = 50.836 (13) Å; V = 4801 (5) Å3; Z = 6, Dcalc = 1.250 g cm−3; µ(Cu Kε) = 11.26 cm−1; 932 unique reflections over the range of 2 < 2θ < 110° (ω/2θ scan mode) were measured; 652 unique observed reflections were used in the refinement with I > 3σ(I); R and Rw = 0.0310 and 0.0329, respectively. Crystal data for 6: C24H57Ga3; Mn = 602.17; rhombohedral space group R3̅c; a = 10.362 (2) Å; c = 50.927 (10) Å; V = 4735.89 (15) Å3; Z = 6, Dcalc = 1.262 g cm−3; µ(Mo Kα) = 13.4 cm−1, 1117 reflections over the range 3.0 < 2θ < 50.0° (θ/2θ scan mode) were measured; 610 reflections with I > 3σ(I) were used in the refinement; R and Rw = 0.044 and 0.0548, respectively.

Original languageEnglish
Pages (from-to)24-29
Number of pages6
Issue number1
StatePublished - 1993

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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