A one-dimensional barium(II) coordination polymer with a coordinated nitro group of 2-nitrobenzoate

Journal of Chemical Sciences

Pallepogu Raghavaiah1¹  Bikshandarkoil R Srinivasan1¹  Santosh Y Shetgaonkar¹ 

[1] Department of Chemistry, Goa University, Goa 403 206$$

关键词: Coordination polymer;    catena-poly[[hexa(aqua)dibarium(II)]bis[(ð?œ‡2-2-nitrobenzoato-O;    O;    ONO2)(ð?œ‡2-2-nitrobenzoato-O;    O;    O')]];    nitro ligation;    tridentate;    monoatomic bridge;    nine coordination.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

The aqueous reaction of barium carbonate with 2-nitrobenzoic acid (2-nbaH) results in the formation of a one-dimensional coordination polymer, catena-poly[[hexa(aqua)dibarium(II)]bis[(𝜇2-2-nitrobenzoate-O,O,O-NO2)(𝜇2-2-nitrobenzoate-O,O,O')]] 1. On heating at 100°C compound 1 is dehydrated to anhydrous barium bis(2-nitrobenzoate) 2. The anhydrous compound can be re-hydrated to 1 on exposure to water vapour. Compounds 1 and 2 were characterized by elemental analysis, IR and UV-Vis spectra, DSC thermograms, weight loss studies and the structure of 1 was determined. 1 and 2 can be thermally decomposed to BaCO3 by heating at 800°C. The polymer [[Ba(H2O)3]2(𝜇2-2-nba-O,O,O-NO2)2 (𝜇2-2-nba-O,O,O')2]𝑛 1 crystallizes in the centrosymmetric triclinic space group P$_{ar{i}}$ and all atoms are located in general positions. The polymeric structure is based on a dimeric unit and consists of three water molecules coordinated to a central Ba(II) and two unique 2-nitrobenzoate (2-nba) anions, one of which (𝜇2-2-nba-O,O,O-NO2) functions as a tridentate ligand and is linked to a Ba(II) through the oxygen atom of the -NO2 group and forms a monoatomic 𝜇2-carboxylate bridge between two symmetry related Ba(II) ions with a Ba$cdots$Ba distance of 4.5726(14) Å. The second unique 2-nba anion (𝜇2-2-nba-O,O,O') also functions as a tridentate ligand with the carboxylate oxygen atoms linked to a Ba(II) ion in a bidentate fashion and one of the carboxylate oxygen atoms forming a monoatomic bridge between two symmetry related Ba(II) ions resulting in a Ba$cdots$Ba separation of 4.5406(15) Å. These differing tridentate 2-nba ligands link {Ba(H2O)3} units into a one-dimensional polymeric chain extending along 𝑏 axis. In the infinite chain each nine coordinated Ba(II) is bonded to three water molecules and further linked to six oxygen atoms of four different 2-nitrobenzoate anions with alternating pairs of Ba(II) ions in the chain bridged by a pair of (𝜇2-2-nba-O,O,O-NO2) and (𝜇2-2-nba-O,O,O') ligands resulting in alternating Ba$cdots$Ba distances of 4.5406(15) and 4.5726(14) Å across the chain.

【 授权许可】

Unknown