COORDINATION CHEMISTRY OF N-METHYLIMIDAZOLE WITH YTTRIUM AND CERIUM

Abstract YCl3 crystallizes in the presence of N-methylimidazole (N-MeIm) to form [YCl2(N-MeIm)5]+ [YCl4(N-MeIm)2]−, 1 or [YCl2(N-MeIm)5]+[C1]-, 2, depending upon crystallization conditions. The bromide analog of 2, [YBr2(N-MeIm)5]+[Br]−, 3, has been obtained from YBr3(THF)3 and N-MeIm. Both 1 and 2 contain seven coordinate pentagonal bipyramidal [YCl2(N-MeIm)5]+ cations which have chloride atoms in the axial ligand positions. The anion in 1 has a trans octahedral geometry. Ceric ammonium nitrate crystallizes from N-MeIm to form Ce(NO3)3(N-MeIm)4, 4, which contains a formally ten-coordinate cerium center. 4 is best described as a seven coordinate distorted pentagonal bipyramid with the NO3 ligands occupying one axial and two equatorial sites. 1 crystallized from N-MeIm in the space group P1 with a = 8.1435 (10) Å, b = 9.0448(8) Å, c = 15.103(2) Å, α = 93.872 (10)°, β = 94.117(11)°, γ = 107.288(9)°, V = 1054.8(2) Å3 and Dcalcd = 1.520 Mg/m−3 for Z = 1. Least squares refinement of the model based on 3375 reflections (|F0| > 2.0σ (|F0|)) converged to a final RF = 3.7%. 2 crystallized from a mixture of YCl3 and trimethylaluminum in N-MeIm in the space group P1 with a = 9.462 (3) Å, b = 12.201 (4) Å, c = 13.087(4) Å, α = 77.53(3)°, β = 73.13(2)°, γ = 76.39(2)°, V = 1387.5(7)Å3 and Dcalcd = 1.450 Mg/m−3 for Z = 2. Least squares refinement of the model based on 3909 reflections (|F0| > 3.0σ (|F0|)) converged to a final RF = 4.7%. 3 crystallized from N-MeIm, was found to be isomorphous with 2 by a unit cell determination. 4 crystallized from a mixture of THF and N-MeIm in the space group P21/n with a = 9.9134(16) Å, b = 18.967(3) Å, c = 13.381(2) Å, β = 90.864(12)°, V = 2515.6(7) Å3 and Dcalcd = 1.728 Mg/m−3 for Z = 4. Least squares refinement of the model based on 5239 reflections (|F0| > 3.0σ (|F0|)) converged to a final RF = 3.9%.