Crystal structures of Cs+-crown ether complexes containing polynuclear mercury iodide anions

Reactions of CsI and HgI2 with benzo-15-crown-5 (B15C5) and 15-crown-5 (15C 5) in an ethanol-acetone mixture produced [Cs(B15C5)(2)](2)[Hg2I6] (1) and {[Cs(15C5)](2)[Hg2I6]}(n) (2), respectively. The structures of the two comp lexes are quite different. Molar ratios of Cs+ :crown ether are 1 : 2 in 1 and 1 : 1 in 2. Complex 1 consists of two Cs(B15C5)(2)(+) cations and a Hg2 I62- anion. Cs+ lies between the two crown-5 ligands, resulting in a sandwi ch-type cation. Cationic Cs(B15C5)(2)(+) and anionic Hg2I62- are linked tog ether by electrostatic interactions and the complex 1 is an ion pair compou nd. Complex 2 consists of infinite [Cs(15C5)](2)[Hg2I6] units. Each structu ral unit contains two Cs(15C5)(+) cations and a Hg2I62- anion. Cs+ is coord inated by five oxygen atoms of 15C5, three iodine atoms of Hg2I62-, and an iodine atom of Hg2I62- in an adjacent structural unit. The interactions bet ween the Cs+ of Cs(15C5)(+) and an I- in Hg2I62- from adjacent structural u nits polymerize the complex 2, resulting in a one-dimensional network struc ture. The anions of Hg2I62- in both complexes are similar. The two mercury atoms are linked through two bridging iodine atoms and each mercury is also coordinated by two terminal iodines. Crystal data for 1: space group P2(1) /c (No, 14), a = 12.253(4), b = 20.945(7), c = 16.110(6) Angstrom, beta = 1 11.0(1)degrees, V = 3860 Angstrom(3), Z = 4, R = 0.082 (R-w = 0.089). Cryst al data for 2: space group P2(1)/c (No. 14), a = 12.157(4), b = 8.546(4), c = 20.666(6) Angstrom, beta = 91.54(3)degrees, V = 2146 Angstrom(3), Z = 4, R = 0.034 (R-w = 0.048).