Catena-poly[[(pentaaqua)(4-nitrobenzoato-O,O')barium(II)](mu-4-nitrobenzoato-O,O')]: A barium(II) coordination polymer showing O-H.O and C-H.O interactions

Abstract

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)](mu-4-nitrobenzoato-O,O')] 1. The polymeric compound [[Ba(H2O)5(4-nba-O,O')](mu-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 (mu-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) angstrom 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.