title: Structural and spectroscopic studies of some adducts of silver(I) halides with thiourea and N-ethyl substituted thioureas.
abstract: Syntheses, single crystal X-ray structural and spectroscopic characterizations are described for a variety of adducts of silver halides with thiourea ('tu'), N-ethylthiourea ('ettu' = EtNH.CS.NH(2)) and N,N'-diethylthiourea ('detu' = EtNH.CS.EtNH). This study greatly extends our knowledge of the complex chemistry of silver(i) halides with tu. The unexpected diversity of composition of such complexes was initially revealed by the powerful mechanochemical/IR method and the structures of several of the new complexes were determined by X-ray crystallographic studies of samples subsequently prepared from aqueous solution. Structural characterizations provide extensive geometrical data for (mononuclear 1 : 3) [XAg(xtu)(3)] arrays (xtu = ettu, detu; X = Cl, Br, I), assisting vibrational spectroscopic assignments. With the parent tu ligand, binuclear ionic forms are obtained: [tu(2)Ag(mu-tu)(2)Agtu(2)]X(2), the chloride as the dihydrate and the bromide as a di(thiourea) dihydrate adduct. With tu 1 : 2 complexes are defined for X = Cl, Br, as isomorphous one-dimensional polymers; AgCl:tu (1 : 1) is a two-dimensional net with six-membered Ag(3)S(3) rings and terminal chloride. Intermediate stoichiometries are defined in AgBr:tu (2 : 3), a one-dimensional polymer of Ag(2)S(2) rhombs linked at the silver atoms, while [Cl(2)Ag(3)(tu)(4)](NO(3)).H(2)O is also a one-dimensional polymer in which chloride and thiourea sulfur atoms link six-membered Ag(3)S(3) rings. Diagnostic bands in the IR and far-IR spectra of all of the synthesized complexes are assigned and interpreted in relation to the structures.
authors.affiliation: Department of Chemistry, University of Auckland, Private Bag 92019, Auckland, New Zealand. ga.bowmaker@auckland.ac.nz
authors.forename: Graham A
authors.initials: GA
authors.lastname: Bowmaker
authors.forename: Chaveng
authors.initials: C
authors.lastname: Pakawatchai
authors.forename: Saowanit
authors.initials: S
authors.lastname: Saithong
authors.forename: Brian W
authors.initials: BW
authors.lastname: Skelton
authors.forename: Allan H
authors.initials: AH
authors.lastname: White
mesh_terms: D018360:Crystallography, X-Ray; D008024:Ligands; D008968:Molecular Conformation; D012834:Silver / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013890:Thiourea / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D008024:Ligands; C035318:diethylthiourea; D012834:Silver; C068093:N-ethylthiourea; D013890:Thiourea