Crystal structure of catena-poly[silver(I)-μ-l-tyrosinato-κ2 O:N]

The title compound, [Ag(C9H10NO3)]n, is a polymeric silver(I) complex of l-tyrosine. The AgI atom is connected to N and O atoms of two different l-tyrosine ligands in an almost linear arrangement, with an Ni—Ag—O1 bond angle of 173.4 (2)° [symmetry code: (i) x + 1, y, z]. The Ag—Ni and Ag—O bond lengths are 2.156 (5) and 2.162 (4) Å, respectively. The polymeric chains extend along the crystallographic a axis. Strong hydrogen bonds of the N—H⋯O and O—H⋯O types and additional C—H⋯O interactions connect these chains into a double-layer polymeric network in the ab plane.

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: WinGX (Farrugia, 2012) and PLATON.  (Ahmad et al. 2006;Kasuga et al. 2011;Nomiya et al. 2000;Nomiya & Yokoyama 2002). These complexes usually exist in the form of polymers and the Ag-O and Ag-N bonds play an important role in exhibiting a wide spectrum of antimicrobial activities. The Ag-O bonding complexes can readily undergo ligand replacement with sulfur containing biological ligands such as proteins (Ahmad et al. 2006;Kasuga et al. 2011;Nomiya et al. 2000;Nomiya & Yokoyama, 2002). The crystal structures of these complexes are also characterized by strong hydrogen bonding. The present report is concerned with the crystal structure of a new polymeric silver(I) complex of L-tyrosine ( Fig. 1), which has been synthesized for various studies.

S2. Experimental
L-Tyrosine (0.18 g, 1.0 mmol) was disolved in 10 ml water by adding 10 drops of 1.0 M NaOH. AgNO 3 (0.17 g, 1.0 mmol) was disolved in 10 ml of acetonitrile. The L-tyrosine solution was slowly added to the AgNO 3 solution and the resulting mixture after filtration was kept in the refrigerator at 0°C for crystallization. After three days, colorless needles of (I) were obtained (yield: 20%, m.p = 547 K).

S3. Refinement
The coordinates of H-atoms of the NH 2 group were obtained from the Fourier map and refined isotropically.  View of the asymmetric unit of the title compound. Thermal ellipsoids are drawn at the 50% probability level. H atoms are shown by small circles of arbitrary radii.

Figure 2
The partial packing (PLATON; Spek, 2009) showing the polymeric network due to C-H···O, N-H···O and O-H···O interactions. H atoms not involved in hydrogen-bonding interactions are omitted for clarity.

catena-Poly[silver(I)-µ-L-tyrosinato-κ 2 O:N]
Crystal data 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 > σ(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.