Preparation and crystal structure of tetraaqua-bis(hydrogenopyridine-2,3-(dicarboxylate)bis(pyridine-2,3-dicarboxylate) hexa silver(I) (Ag 6(C 7H 4NO 4) 2(C 7H 3NO 4) 2(H 2O) 4] n

Abstract

The title compound was precipitated by the action of freshly prepared Ag 2O on an aqueous solution of pyridine-2,3-dicarboxylic acid. The white compound was redissolved in hot water and crystals suitable for X-ray diffraction study were grown. The crystal is a polymeric network; five-membered chelate rings (-CNAgOC-) and dimeric units (AgOCO′) 2 sequenced in two types of similar chains linked by AgAg bonds and short intermolecular hydrogen bonds are presented simultaneously. The four Ag atoms of the asymmetric unit show two different environments. Ag(1) and Ag(2), sitting on a symmetry centre, are each included in two chelating rings. So, Ag(1) and Ag(2) are in four-coordinated planar environments: Ag(1)N(21) = 2.166(5), Ag(1)O(24) = 2.705(4), Ag(2)N(11) = 2.172(4), Ag(2)O(11) = 2.706(5) Å, N(21)Ag(1)-(1)(24) = 67.7(2), N(11)Ag(2)O(11) = 68.4(2)°. Ag(3) Ag(4) are included in eight-membered rings, (AgOCO′) 2 with bipyramidal trigonal arrangement constituted by two Ag atoms [Ag(3)(3 ii) = 2.843(2), Ag(3)Ag(4 i) = 3.090(2), Ag(4)Ag(4 v) = 2.894(1) Å, two oxygen carboxylic atoms [Ag(3)0223) = 2.271(5), Ag(3)O(24 ii) = 2.245(4), Ag(4)O(12 v) = 2.236(6), Ag(4)= 2.242(6) Å] and one aqueous oxygen atom Ag(3)O(wl) = 2.329(6), Ag(4)O(w2) = 2.399(5) Å]. The H carboxylic hydrogen atoms of the hydrogenopyridine-2,3-dicarboxylate ligands being split between two carboxylate groups are involved in short intermolecular hydrogen bonds between two carboxylic groups: 0(13) … 0(22 ii) = 2.459(4) Å.