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Strukturen zweier Salze des Bis(thioharnstoff)gold(I)-Kations

Strey, Mark, Jones, Peter G.
Zeitschrift für Naturforschung 2018 v.73 no.5 pp. 349-354
cations, crystal structure, crystallization, gold, hydrogen bonding, isopropyl alcohol, ligands, methanol, oxygen, sulfates, thiocyanates, thiourea
Attempts to isolate the compound (tu₂Au)SCN 1 (tu=thiourea), first reported in 1949, at first led to [(tu)₂Au]₂SO₄·CH₃OH 2 after crystallization from methanol-petroleum ether. Crystallization from isopropanol led to the required compound 1. The crystal structure analysis of 1 confirmed its ionic nature, (tu₂Au)⁺ SCN⁻. The tu ligands are mutually trans (torsion angle C–S···S–C 175.4(2)°), and the entire cation is approximately planar (r.m.s. deviation 0.08 Å). Eight classical hydrogen bonds connect the residues to form layers parallel to the bc plane at x≈⅛, ⅜, ⅝ and ⅞; the layers are connected by aurophilic contacts, which link the cations to form chains parallel to the a axis. In the structure of compound 2 the S=C groups are synclinal to each other; two NH₂ groups are connected via a bifurcated hydrogen bonding system to a sulfate oxygen, forming a ring of graph set R21(10).${\rm{R}}_2^1(10).$ In a complex three-dimensional packing, the cations are connected by various interactions to form layers parallel to the ac plane at y≈½, whereas the sulfates are the centres of hydrogen-bonded double layers on both sides of the mirror plane at y≈¾. The structure contains a convincing example of a hydrogen bond to a gold centre.