(μ-3,5,9,11-Tetraoxo-4,10-diazatetracyclo[5.5.2.02,6.08,12]tetradec-13-ene-4,10-diido-κ2 N:N′)bis[(2,2′-bipyridine-κ2 N,N′)silver(I)] dihydrate

In the title complex, [Ag2(C12H8N2O4)(C10H8N2)2]·2H2O, the AgI ion is three-coordinated by two N atoms from a chelating 2,2′-bipyridine ligand and one N atom from an imide ligand in a Y-shaped fashion. The imide ligand and the complex lie on a twofold rotation axis. The ligand bridges two AgI ions, forming a dinuclear complex. In the crystal, O—H⋯O hydrogen bonds link the lattice water molecules and the complex molecules into a ribbon-like structure along [001]. π–π interactions are observed between the pyridine rings [centroid–centroid distance = 3.8289 (14) Å].

In the title complex, [Ag 2 (C 12 H 8 N 2 O 4 )(C 10 H 8 N 2 ) 2 ]Á2H 2 O, the Ag I ion is three-coordinated by two N atoms from a chelating 2,2 0 -bipyridine ligand and one N atom from an imide ligand in a Y-shaped fashion. The imide ligand and the complex lie on a twofold rotation axis. The ligand bridges two Ag I ions, forming a dinuclear complex. In the crystal, O-HÁ Á ÁO hydrogen bonds link the lattice water molecules and the complex molecules into a ribbon-like structure along [001].

Comment
The assembly of mixed-ligand coordination polymers has attracted great attention due to their intriguingly complicated architectures and potential applications in adsorption, separation and magnetism (Song et al., 2012;Wang, 2010).
Molecular building blocks associated with polydentate carboxylic acids are widely used in chiral catalysis, optoelectronic materials, hematopathology and medicine (Liao et al., 2008;Wang et al., 2009). In our laboratory, we synthesized a new silver(I) complex constructed by an amide molecule in combination with 2,2-bipyridine as ancillary ligand.
In the title complex, the amide ligand lies on a twofold rotation axis and bridges two 2,2′-bipyridine-chelated Ag I atoms.

Refinement
H atoms on C atoms were positioned geometrically and refined as riding atoms, with C-H = 0.93 and 0.98 Å and with U iso (H) = 1.2U eq (C). H atoms bonded to O atoms were located in a difference Fourier map and refined with O-H distance restraints of 0.85 (2) Å and with U iso (H) = 1.5U eq (O).  The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level.

Computing details
[Symmetry code: (i) 1-x, y, 1/2-z.]  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.