Synthesis, crystal structure and spectroscopic characterization of an oxalato bridged silver-deficient chromium(III) salt with water-filled nanochannels

The reaction of K-3[Cr(C2O4)(3)]center dot 3H(2)O with AgNO3 in water afforded the non-stoichiometric nanostructured silver salt, {Ag0.26K0.24[Ag2.5Cr(C2O4)(3)]center dot 3H(2)O}(n) (1) which was characterized by elemental analysis, EDX, IR and UV-VIS spectroscopies and single crystal X-ray diffraction. Compound (1) crystallizes in a monoclinic space group C2/c, with unit cell parameters a = 18.2556(5), b = 14.6784(3), c = 12.2823(3) angstrom, beta = 113.527(3)degrees, V = 3017.78(13) angstrom(3), Z = 8. The Cr(III) centers in the crystal structure are hexacoordinated by the oxalato-O atoms in a distorted octahedral geometry. Compound (1) is a new member of the broad family of silver-deficient oxalatometalate(III) salts with water-filled nanochannels generally formulated as [(MxAg0.50-x)(H2O)(3)]@[Ag2.50Cr(C2O4)(3)], with 0 <= x <= 0.50; M = K, Cs, Ag. The structure is best described as a non-molecular coordination polymer where the host lattice is constructed by the three-dimensional interconnectivity of the metallic centers through the O atoms of the oxalates and waters.