CROWN-ETHER COMPLEXES OF LEAD(II) - THE CRYSTAL-STRUCTURES OF [PBCL(18-CROWN-6)][SBCL6], [PB(18-CROWN-6)(CH3CN)3][SBCL6]2, AND [PB(15-CROWN-5)2][SBCL6]2

[PbCl(18-crown-6)][SbCl6] has been prepared in low yield besides [Pb(CH3)2(18-crown-6)][SbCl6]2 by the reaction of Pb(CH3)2Cl2 with antimony pentachloride in acetonitrile solution in the presence of 18-crown-6, forming pale-yellow crystals. The other two title compounds are formed as colourless crystals by the reaction of PbCl2 with antimony pentachloride in acetonitrile solutions in the presence of 18-crown-6 and 15-crown-5, respectively. The complexes were characterized by IR spectroscopy and by crystal structure determinations. [PbCl(18-crown-6)][SbCl6]: Space group P2(1)/c, Z = 8, 5003 observed unique reflections, R = 0.046. Lattice dimensions at 80-degrees-C: a = 13 86.9; b = 1 642.7; c = 2 172.1 pm, beta = 92.95-degrees. The lead atom in the cation [PbCl(18-crown-6)]+ is surrounded in an almost hexagonal-planar construction by the six oxygen atoms of the crown ether and an axially oriented Cl atom. [Pb(18-crown-6)(CH3CN)3][SbCl6]2: Space group P1BAR, Z = 2, 6 128 observed unique reflections, R = 0.076. Lattice dimensions at -70-degrees-C: a = 1 228.0; b = 1422.9; c = 1 463.2 pm, alpha = 69.08-degrees; beta = 65.71-degrees; gamma = 64.51-degrees. In the cation [Pb(18-crown-6)(CH3CN)3]2+ the lead atom is coordinated by the six oxygen atoms of the crown ether and by the three nitrogen atoms of the acetonitrile molecules. The structure determination is restricted by disorder. [Pb(15-crown-5)2][SbCl6]2: Space group P6(3)/m, Z = 6, 5 857 observed unique reflections, R = 0.059. Lattice dimensions at -70-degrees-C: a = b = 2 198.5; c = 1 499.4 pm, (alpha = beta = 90-degrees, gamma = 120-degrees. In the cation [Pb(15-crown-5)2]2+ the lead atom is sandwich-like coordinated by the ten oxygen atoms of the two crown ether molecules. The structure determination is restricted by disorder.