Inorganic Chemistry, Vol.37, No.20, 5070-5077, 1998
Silver-thioether crown complexes as templates for the synthesis of extended polyiodide networks : Synthesis and x-ray crystal structures of [Ag-2([15]aneS(5))(2)]I-12, [Ag([18]aneS(6))]I-7, [Ag([18]aneS(6))]I-3, and [Ag([9]aneS(3))(2)]I-5
Silver(I) complexes of [9]aneS(3), [15]aneS(5), and [18]aneS(6) have been used as templates for the self-assembly of polyiodide ions. The complexes [Ag-2([15]aneS(5))(2)]I-12, [Ag([18]aneS(6))]I-7, [Ag([18]aneS(6))]I-3, and [Ag([9]aneS(3))(2)]I-5 have been synthesized and structurally characterized. In [Ag-2([15]aneS(5))(2)]I-12 [C10H20AgI6S5, orthorhombic, space group Pna2(1) with a = 21.688(4) Angstrom, b = 27.748(4) Angstrom, c = 8.623(2) Angstrom, Z = 8], a discrete I-12(2-) polyiodide anion describable as a [2I(-).5I(2)] charge-transfer adduct is bound to two [Ag([15]aneS(5))](+) cations by Ag-I bonds. I ... S interactions contribute to build up an extended three-dimensional superstructure featuring spirals of I-12(2-) and [Ag([15]aneS(5))](+) ions alternating along the c axis. In [Ag([18]aneS(6))]I-7 [C12H24AgI7S6, trigonal, space group R (3) over bar m with a = b = c = 9.458(4) Angstrom, alpha = beta = gamma = 103.79(3)degrees, Z = 1], the Ag(I) complex cation is embedded in a unique three-dimensional polyiodide matrix in which I- ions occupy the lattice points of a primitive rhombohedral lattice with one I-2 molecule bridging two I- ions along each cell edge to give a pseudo-perovskite structure. [Ag([(18)]aneS(6))]I-3 [C12H24AgI3S6, monoclinic, space group C2/m with a = 18.5767(11) Angstrom, b = 11.9188(7) Angstrom, c = 5.2714(5) Angstrom, beta = 95.634(9)degrees, Z = 2] features discrete [Ag([18]aneS(6))](+) cations and I-3(-) in a columnar stacking arrangement. Using the [Ag([9]aneS(3))(2)](+) cation as template, an I-5(-) salt has been obtained : this contrasts with the cubelike [I-7(-)](infinity) polyiodide array and I-3(-) salt isolated with the [Ag([18]aneS(6))](+) cation. In [Ag([9]aneS(3))(2)]I-5 [C12H24AgI5S6, monoclinic, space group C2/c with a = 17.1117(12) Angstrom, b = 12.612(2) Angstrom, c = 14.016(2) Angstrom, beta = 118.65(4)degrees, Z = 4]. I ... S interactions contribute to an extended structure featuring polymeric successions of cations and I-5(-) ions. The solid-state FT-Raman spectra of these polyiodides are discussed on the basis of their crystal structures.
Keywords:REDOX PROPERTIES;FT-RAMAN;POLYHALIDES;CHEMISTRY;OXIDATION;CATION;HEPTAIODIDE;IODINE;ION;HEXADECAIODIDE