SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF BARIUM COMPLEXES CONTAINING THE BULKY AMINO SILOXIDE HYBRID LIGAND (OSI)-O--((T)BU)(2)((CH2)(3)NME(2))

The bulky amino-siloxide hybrid ligand (OSi)-O--((t)Bu)(2)((CH2)(3)NMe (2)) allows isolation of dinuclear, hydrocarbon-soluble barium complex es. The structures of two mono(ligand) complexes, {Ba[OSi((1)Bu)(2) (( CH2)(3)NMe(2))][N(SiMe(3))(2)]}(2) (1) and (t)Bu)(2)((CH2)(3)NMe(2))][ N(SiMe(3))(2)][THF]}(2) (3), have been determined by X-ray diffraction (crystal data: 1, monoclinic, C2/c, a = 20.451(4) Angstrom, b = 14.27 7(3) Angstrom, c = 22.258(5) Angstrom, beta = 101.14(2)degrees, V = 63 76.1(2) Angstrom(3), Z = 4 (dimers), R = 0.069, R(w) = 0.100; 3, monoc linic, P2(1)/c, a = 11.025(4) Angstrom, b = 22.414(3) Angstrom, c = 13 .925(2) Angstrom, beta = 104.05(2)degrees, V = 3338.0(1) Angstrom(3), Z = 2 (dimers), R = 0.090, R(w) = 0.117). Complex 1 is stable towards ligand redistribution in d(6)-benzene or d(8)-toluene, but in d(8)-THF both 1 and 3 exist in equilibrium with the ligand redistribution prod ucts Ba[N(SiMe(3))(2)](2)[THF](2) and Ba[OSi((t)Bu)(2)((CH2)(3)NMe(2)) ](2) (2). Complex 2 was prepared independently and appears to exist as a monomer-dimer equilibrium in d(6)-benzene solution. Complexes 1-3 d o not sublime when heated under high vacuum (200 degrees C, 10(-4) Tor r).