Poly[[μ3-chlorido-bis(μ2-thiourea-κS)disilver(I)] nitrate]

The molecular structure of the title polymeric complex, {[Ag2Cl(CH4N2S)2]NO3}n, consists of a binuclear cationic complex and a nitrate counter-ion. The cationic complex contains two bridging thiourea (Tu) ligands and a triply bridging μ3-Cl anion. The latter is probably released from 2-aminoethanethiol hydrochloride during the synthesis. The coordination environment around the two AgI atoms is different; one is trigonal planar, being coordinated by two thiourea ligands through the S atoms and to one Cl− ion, while in the other the AgI atom is tetrahedrally coordinated by two thiourea ligands through the S atoms and to two Cl− ions. These units aggregate through the Cl− anion and the Tu S atoms, forming a chain propagating in [100]. In the crystal structure, the polymeric chains are linked via N—H⋯O and N—H⋯Cl hydrogen bonds, forming a double layer two-dimensional network propagating in (011).

MA and HSE thank the staff of the X-ray Application Lab, CSEM, Neuchâ tel, for access to the X-ray diffractometer.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5309).

Comment
The study of the coordination and structural chemistry of silver(I) complexes with sulfur containing ligands has been a matter of interest over the last decades due to their wide range of applications in medicine and in analytical chemistry (Raper, 1996;Akrivos, 2001), and also due to their ability to adopt geometries with variable nuclearities and structural diversity.
The molecular structure of the title complex is shown in Fig. 1. The asymmetric unit consists of a binuclear cationic complex and a nitrate counter ion. The cationic complex contains two silver(I) atoms, Ag1 and Ag2, two Tu ligands which bridge the silver(I) atoms via the S-atoms, and a triply bridging (µ 3 )Clanion. The latter is probably released from 2-aminoethanethiol hydrochloride during the synthesis. The coordination environments around the two silver atoms are different.
Atom Ag1 possesses a tetrahedral geometry, being coordinated to two thiourea ligands through the S-atoms, and two Clanions. Atom Ag2 has a trigonal planar geometry, being coordinated to two thiourea ligands through S-atoms and to one Clanion. These units aggregate through the Clanion, and the Tu sulfur atoms, to form a one-dimensional chain which propagates in [100], as shown in Fig. 1.
In the crystal the polymeric chains are linked via N-H···O hydrogen bonds, involving the thiourea NH 2 H-atoms and the nitrate O-atoms, and N-H···Cl contacts (Fig. 2, Table 1), to form a double layer two-dimensional network propagating in plane (011).

supplementary materials sup-2 Experimental
The title complex was prepared by adding 1 mmol (0.113 g) of 2-aminoethanethiol hydrochloride, dissolved in 10 ml of distilled water, to 1 mmol (0.170 g) of AgNO 3 , dissolved in 30 ml of distilled water. The mixture was stirred for 15-20 min giving a clear solution. 1 mmol (0.076 g) of thiourea, dissolved in 10 ml of methanol, was then added and the mixture was stirred for a further 15 min. The solution was then filtered and the filtrate kept at RT for slow evaporation of the solvent.
After 2-3 days colourless crystals, suitable for X-ray diffraction analysis, were obtained.

Refinement
The NH 2 H-atoms could be located in difference electron-density maps. In the final cycles of least-squares refinement they were included in calculated positions and treated as riding atoms: N-H = 0.88 Å, with U iso (H) = 1.2U eq (N). Fig. 1. A view of the molecular structure of the title complex with displacement ellipoids drawn at the 50% proability level [Symmetry codes: (a) = -1 + x, y, z;  Table 1 for details].