Graham A. Bowmaker, Effendy, Brian W. Skelton, Neil Somers, Allan H. White
The meagre (structurally defined) array of 1:2 silver(I) (pseudo-)halide:unidentate nitrogen base adducts is augmented by the single-crystal X-ray structural characterization of the 1:2 silver(I) thiocyanate:piperidine ('pip') adduct. It is of the one-dimensional 'castellated polymer' type previously recorded for the chloride: ⋯Ag(pip) 2(μ-SCN)Ag(pip)2⋯ a single bridging atom (S) linking successive silver atoms. By contrast, in its copper(I) counterpart, also a one-dimensional polymer, the thiocyanate bridges as end-bound SN-ambidentate: ⋯CuSCNCuSCN⋯ A study of the 1:1 silver(I) bromide:quinoline ('quin') adduct is recorded, as the 0.25 quin solvate, isomorphous with its previous reported 'saddle polymer' chloride counterpart. Recrystallization of 1:1 silver(I) iodide:tris(2,4,6-trimethoxyphenyl)phosphine ('tmpp') mixtures from py and quinoline ('quin')/acetonitrile solutions has yielded crystalline materials which have also been characterized by X-ray studies. In both cases the products are salts, the cation in each being the linearly coordinated silver(I) species [Ag(tmpp)2]+, while the anions are, respectively, the discrete [Ag5I7(py)2]2- species, based on the already known but unsolvated [Cu5I 7]2- discrete, and the [Ag5I7] (∞|∞)2- polymeric, arrays, and polymeric [Ag5I6(quin)](∞|∞)-. The detailed stereochemistry of the [Ag(tmpp)2]+ cation is a remarkably constant feature of all structures, as is its tendency to close-pack in sheets normal to their P-Ag-P axes. The far-IR spectra of the above species and of several related complexes have been recorded and assigned. The vibrational modes of the single stranded polymeric AgX chains in [XAg(pip) 2](∞|∞) (X = Cl, SCN) are discussed, and the assignments ν(AgX) = 155, 190 cm-1 (X = Cl) and 208 cm -1 (X = SCN) are made. The ν(AgX) and ν(AgN) modes in the cubane tetramers [XAg(pip)]4 (X = Br, I) are assigned and discussed in relation to the assignments for the polymeric AgX:pip (1:2) complexes, and those for the polymeric [XAg(quin)](∞|∞) (X = Cl, Br) compounds. The far-IR spectra of [Ag(tmpp)2]2[Ag 5I7(py)2] and its corresponding 2-methylpyridine complex show a single strong band at about 420 cm-1 which is assigned to the coordinated tmpp ligand in [Ag(tmpp)2] +, and a partially resolved triplet at about 90, 110 and 140 cm -1 which is assigned to the ν(AgI) modes of the [Ag 5I7L2]2- anion. An analysis of this pattern is given using a model which has been used previously to account for unexpectedly simple ν(CuI) spectra for oligomeric iodocuprate(I) species. © 2005 Elsevier B.V. All rights reserved.
Department of Chemistry, University of Auckland, Auckland, Private Bag 92019, New Zealand; Chemistry M313, University of Western Australia, Crawley, WA 6009, Australia; Jurusan Kimia, FMIPA Universitas Negeri Malang, Malang 65145, Jalan Surabaya 6, Indonesia
