SYNTHESES AND CHARACTERIZATION OF THE GALLIUM PHOSPHORUS CAGES ((ET2O)2LI)(T-BUGA)(P(T-BU))2(GA(T-BU)2) AND ((T-BU)2GA)(T-BUGA)(P(T-BU))2(GA(T-BU)2)

The novel cage compounds {(Et2O)2Li}{t-BuGa}{P(t-Bu)}2{Ga(t-BU)2}(1) a nd {(t-BU)2Ga}{t-BuGa}{P(t-Bu)}2{Ga(t-BU)2} (2) were synthesized in Et 2O solution by the reaction of Li2P(t-Bu) with 1 or 2 equiv of (t-Bu)2 GaCl. They were characterized by X-ray crystallography and variable te mperature (VT) H-1 and P-31 NMR spectroscopy. In the crystal, 1 and 2 have a distortedtrigonal-bipyramidal LiGa2P2 or Ga3P2 core structure. Each compound contains four-coordinate phosphorus and both three- and four-coordinate gallium centers. A proposed mechanism for the formatio n of 1 and 2 and related compounds is also discussed. Crystal data wit h Mo Kalpha radiation (lambda = 0.710 69 angstrom) at 130 K: 1, C28H65 Ga2LiO2P2, a = 10.277(5) angstrom, b = 17.439(7) angstrom, c = 11.212( 5) angstrom, beta = 115.12(3)-degrees, monoclinic, space group P2(1) Z = 2, R = 0.059; 2, C28H63Ga3P2, a = 17.236(4) angstrom, b = 11.970(3) angstrom, c = 16.958(4) angstrom, beta = 91.98(2)-degrees, monoclinic , space group C2/c, Z = 4, R = 0.063.