Bis(1,3-benzothiazol-2-amine-κN 3)silver(I) nitrate acetone solvate

In the title compound, [Ag(C7H6N2S)2]NO3·C3H6O, the AgI ion is coordinated to two benzothiazol-2-amine ligands via the thiazole N atoms in an approximately linear arrangement. The dihedral angle between the mean planes of the two 1,3-benzothiazole groups is 5.9 (3)°. Both amine groups on the ligands are oriented in the same direction and are engaged in N—H⋯O hydrogen bonding with the nitrate counter-anion, forming one-dimensional columns along the b-axis direction. Voids created by inefficient crystal packing are occupied by acetone solvent molecules which are disordered over two sites with occupancies of 0.563 (11) and 0.437 (11).

In the title compound, [Ag(C 7 H 6 N 2 S) 2 ]NO 3 ÁC 3 H 6 O, the Ag I ion is coordinated to two benzothiazol-2-amine ligands via the thiazole N atoms in an approximately linear arrangement. The dihedral angle between the mean planes of the two 1,3benzothiazole groups is 5.9 (3) . Both amine groups on the ligands are oriented in the same direction and are engaged in N-HÁ Á ÁO hydrogen bonding with the nitrate counter-anion, forming one-dimensional columns along the b-axis direction. Voids created by inefficient crystal packing are occupied by acetone solvent molecules which are disordered over two sites with occupancies of 0.563 (11) and 0.437 (11).

S1. Comment
The cation in the title compound (I) (Fig. 1) is crystallographically independent and consists of two benzothiazol-2-amine ligands coordinating to an Ag I ion with their thiazole imine nitrogen atoms, thus furnishing an essentially linear geometry around the metal. This is in contrast to a postulation of amino-N coordination by Tewari et al. (1991) which was based on infrared evidence. However, hydrogen bonding may have interfered in the assignment of bands. Their conclusions that nitrate is not bonded to silver and the presence of Ag···S contacts have now been verified for the structure of (I).
The nitrate counter-anion in (I) does not interact with the metal which is reflected in the close to linear N-Ag-N angle of 171.84 (17)°. Similar molecular structures wherein the Ag I ion is coordinated to two thiazole imine nitrogen atoms and interacts with nitrate, have markedly bent angles of 143.2 (2) and 146.1 (2)° (Fitchett & Steel, 2000), The planes of the two 1,3-benzothiazole groups in (I) lie at an angle of 5.9 (3)° which prevents crowding between H19 and H29 that would otherwise ensue in a flat cation. A short contact between Ag1 and S11 i [3.2261 (15) Å, symmetry code: (i) = x, y + 1, z] can be observed which is shorter than the sum of the van der Waals radii of the concerned atoms.
Such Ag···S interactions involving thiazole rings have been observed before with distances of 3.306 Å (Ellsworth et al., 2006), 3.336 Å (Fackler Jr et al., 1992) The nitrate counteranion plays a crucial role in governing the crystal structure of (I). The amino groups of the cations engage in hydrogen bonds to the nitrate anion and form polar one-dimensional hydrogen bonding domains ordered around the crystallographical 2 1 screw axes. The apolar 1,3-benzothiazole "ends" of different columns face each other as well as the co-crystallized acetone solvent molecules (Fig. 2). The hydrogen bonding network ( Fig. 1) emanates from the two amino groups of the cation which chelate O1 of the nitrate anion as well as hydrogen bonding to two other nitrates, one from the same side of the chain (via O2, related by a translation in b) and one from the other side (via O1, related by a 2 1 screw operation). O1 accepts three hydrogen bonds and O2 is involved in a single hydrogen bond. O3 does not exhibit hydrogen bonding which might be a cause of its larger thermal ellipsoid due to less restriction in movement.
The acetone solvent is highly disordered and occupies two sites in a 0.56:0.44 ratio. The carbonyl groups roughly point in opposite directions. Additional electron density peaks around the solvent as well as very high U eq values suggest a high mobility of the acetone molecule.

S3. Refinement
To obtain a satisfactory geometry, the bond lengths in both orientations of the acetone molecule were restrained to target distances (C=O 1.2 Å and C-C 1.5 Å) and the molecules themselves restrained to be flat. The occupancies for the A and B orientation refined to 0.563 (11) and 0.437 (11), respectively.
All H atoms were positioned geometrically (C-H = 0.95, 0.99 and 0.98 Å for CH, CH 2 and CH 3 groups, respectively; N-H = 0.92 Å) and constrained to ride on their parent atoms; U iso (H) values were set at 1.2 times U eq (C,N) except for methyl groups where U iso (H) was set at 1.5 times U eq (C).
The largest residual electron density peak of 1.91 e Å -3 is located 0.68 Å from O4A of the acetone solvent molecule, the largest hole of -1.06 e Å -3 is located 0.54 Å from O4B.  The asymmetric unit of (I), ellipsoids are drawn at the 50% probability level; the disordered acetone molecule and hydrogen atoms not involved in hydrogen bonding are omitted. A part of the symmetry-related 1,3-benzothiazole moiety that forms the Ag1···S11 i contact is shown as a stick model. Symmetry codes: (i) = x, y + 1, z; (ii) = x, y-1, z; (iii) = -x+3/2, y + 1/2, -z+1/2; (iv) = -x+3/2, y-1/2, -z+1/2.  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger. The acetone molecule is disordered around two positions with the C-O vectors pointing in roughly opposite directions. The bonds were restrained to target distances (1.2 Å for C═O and 1.5 Å for C-C) and the molecules were restrained to be flat. Due to the heavy disorder, anisotropic refinement of the molecule was not possible.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (