URANIUM POLY(PYRAZOL-1-YL)BORATE COMPLEXES - X-RAY CRYSTAL-STRUCTURES OF UCL2CP[HB(3,5-ME2PZ)3] AND UCL3[HB(3,5-ME2PZ)3]

The crystal and molecular structures of UCl2Cp[HB(3,5-Me2Pz)3] (1) and UCl3[HB(3,5-Me2Pz)3] (2) have been determined by single crystal X-ray diffraction. Compound 1 crystallizes in space group P1, a = 10.770(1), b = 11.146(5), c = 11.820(4) Å, α = 114.53(2), β = 91.70(2), γ = 107.45(2)°, V = 1211.77 Å3, Z = 2; compound 2 crystallizes in space group P21/c, a = 8.173(1), b = 14.279(3), c 19.167(7) Å, β = 100.17(2)°, V = 2201.71 Å3, Z = 4. In both compounds the uranium centre is six-coordinate and displays octahedral geometry, close to Cs, symmetry for complex 1 and to C3v symmetry for complex 2. For compound 1 the average UCl, UN and UC(Cp) bond distances are 2.60(1), 2.51(2) and 2.74(1) Å; for 2 the average UCl and UN bond distances are 2.56(1) and 2.43(1) Å. © 1990.