catena-Poly[[(pentaaqua)(4-nitrobenzoato-O,O′)barium(II)] (μ-4-nitrobenzoato-O,O′)]: A barium(II) coordination polymer showing O–H⋅⋅⋅O and C–H⋅⋅⋅O interactions*

The reaction of barium carbonate with 4-nitrobenzoic acid (4-nbaH) results in the formation of a Ba(II) coordination polymer, catena-poly[[(pentaaqua)(4-nitrobenzoato-O,O′)barium(II)](μ-4-nitrobenzoato- O,O′)] 1. The polymeric compound [[Ba(H2O)5(4-nba-O,O′)](μ-4-nba-O,O′)]n 1 was characterized by elemental analysis, IR and UV–Vis spectra, weight loss studies, X-ray powder diffraction and its structure determined. In 1 five water molecules are coordinated to the central metal and one of the 4-nba ligands is bonded to Ba(II) in a bidentate manner (4-nba-O,O′) through the carboxylate O atoms. The [(pentaaqua)(4-nitrobenzoato-O,O′)barium(II)] units are linked into an infinite one-dimensional chain along b-axis with the aid of the second 4-nba anion, which functions as a bridging bidentate (μ-4-nba- O,O′) ligand. This results in nine coordination around each Ba(II) ion in the coordination polymer. A long Ba⋅⋅⋅Ba distance of 6⋅750(1) Å is observed between adjacent Ba(II) ions in the chain and the oxygen atoms of the carboxylate group and the nitro functionalities of the 4-nba ligand are involved in several O–H⋅⋅⋅O and C–H⋅⋅⋅O interactions