Reference

1,2,4,5-Benzenetetracarboxylic acid and 4,4'-bipyridine as ligands in designing low-dimensional coordination polymers

1,2,4,5-Benzenetetracarboxylic acid and 4,4'-bipyridine as ligands in designing low-dimensional coordination polymers. Ruiz-Perez, Catalina; Lorenzo-Luis, Pablo; Hernandez-Molina, Maria; Laz, M. Milagros; Delgado, Fernando S.; Gili, Pedro; Julve, Miguel ( Laboratorio de Rayos X y Materiales Moleculares, Dpto. de Fisica Fundamental II, Avda, Astrofisico Francisco Sanchez s/n. Facultad de Fisica, Universidad de La Laguna, Tenerife 38204, Spain). European Journal of Inorganic Chemistry, (19), 3873-3879 (English) 2004 Wiley-VCH Verlag GmbH & Co. KGaA. CODEN: EJICFO. ISSN: 1434-1948. DOCUMENT TYPE: Journal CA Section: 78 (Inorganic Chemicals and Reactions) Section cross-reference(s): 75 The combined use of 1,2,4,5-benzenetetracarboxylic acid (H4bta) and 4,4'-bipyridine (bpy) as ligands with MnII and CoII ions afforded two polymeric compds. [Mn(Hbta)(Hbpy)(H2O)2] (1) and [H2bpy][Co(bta)(bpy)(H2O)2] (2). 1 And 2 were prepd. under hydrothermal conditions (145°, 3 h) and characterized by elemental anal., IR spectroscopy, TG-DTA anal. and single-crystal x-ray diffraction methods. 1 Exhibits a novel double chain structure growing along the b axis where the Mn atoms are linked by tris-monodentate Hbta3- ligands. The values of the Mn×××manganese intrachain sepns. are 7.627(2) ? [Mn(1)×××Mn(1c); c = -x + 1/2, yr - 1/2, -z] and 9.274(4) ? [Mn(1)×××Mn(1d); d = x, y + 1, -z]. Adjacent double chains in 1 are further linked through H bonds between the NH fragment of the Hbpy+ cation and one of the carboxylate groups of the Hbta3- anion along the a axis, resulting in a sheetlike structure. 2 Exhibits a rectangular grid arrangement of Co atoms bridged by bis-monodentate bta4- and bpy ligands in the bc plane, the Co×××cobalt sepns. across them being 6.228(2) and 10.074(2) ?, resp. The metal atoms in 1 and 2 are six-coordinate with two H2O mols. in trans positions (1 and 2), three (1)/two (2) carboxylate O atoms and one (1)/two (2) pyridyl N atoms forming a distorted octahedral environment. The varying nature of the divalent metal ions [Mn 1 and Co 2] along with the differing degrees of protonation of the tetracarboxylate [Hbta3- 1 and bta4- 2] and bipyridyl [Hbpy+ 1 and bpy and H2bpy2+ 2] species account for the structural differences between 1 and 2.

Chemical surface-modification of a polyimide: characterization and a kinetic study on the diffusion of ions in a modified polymer

Chemical surface-modification of a polyimide: characterization and a kinetic study on the diffusion of ions in a modified polymer. Plechaty, Miro M.; Thomas, Richard R. (Thomas J. Watson Res. Cent., IBM, Yorktown Heights, NY 10598, USA). J. Electrochem. Soc., 139(3), 810-21 (English) 1992. CODEN: JESOAN. ISSN: 0013-4651. DOCUMENT TYPE: Journal CA Section: 38 (Plastics Fabrication and Uses) Section cross-reference(s): 35, 37 1,2,4,5-Benzenetetracarboxylic acid dianhydride-4,4'-oxydianiline is surface modified via treatment with aq. alkali metal hydroxide solns. followed by ion exchange with protons which leaves the modified region of the polyimide rich in carboxylic acid groups. The carboxylic acid groups are capable of complexing metal salts. For example, a Pd2+ salt forms a 1:1 complex with the amic acid groups. The modified polyimide is characterized by XPS and capacity measurements. The modified polyimide is a polyelectrolyte and, when in contact with an electrolyte soln., is subject to ion exchange. The kinetics of ion exchange in this modified polyimide, initially in the form of the Pd salt of amic acid, in contact with a Na ion-contg.There are some commonly used reagents with their cas registry numbers 25038-81-7 and 140608-24-8 in this article. soln. are investigated. The rate of ion exchange was diffusion-controlled. The kinetic results obey the Fickian equations for diffusion after a modification to account for time-dependent diffusion coeffs. The measured interdiffusion coeffs. are in the range 10-10 to 10-15 cm2 s-1. .