Hexaaquacobalt(II) bis[(4-oxo-4H-pyridin-1-yl)acetate] dihydrate

Abstract

The title complex, [Co(H 2 O) 6 ](C 7 H 6 NO 3) 2 Á2H 2 O, was synthesized by the reaction of Co(CH 3 COO) 2 Á4H 2 O and 4-oxo-4Hpyridine-1-acetic acid in an aqueous solution. The cobalt(II) ion, which lies on a center of symmetry, is coordinated by six water molecules to form an octahedron [CoÐO = 2.077 (1)± 2.084 (1) A Ê ]. A three-dimensional supramolecular framework is formed via OÐHÁ Á ÁO hydrogen bonds between the anions and cations.

(4-Oxo-1,4-dihydropyridin-1-yl)acetic acid

“…A carboxysubstituted derivative has been synthesized; the carboxy group does not retain the acid H atom but instead concedes it to the acetate unit in C 5 H 4 (3-CO 2 )NCH 2 CO 2 H (Chen & Mak, 1991). Our interest in the theoretical and solid-state structure of the 4-hydroxy-substituted pyridinioacetate is related to the existence of the [O C(CH CH) 2 NÐCH 2 ÐCO 2 ] À anion in the hexaaquacobalt(II) (Zhang et al, 2004a), hexaaquanickel(II) (Zhang et al, 2004b) and hexaaquazinc(II) (Gao et al, 2004) salts, whose anions possess unambiguous doubly bonded O atoms connected to the ring. The 3,5-diiodo-substituted compound, on the other hand, exists as a carboxylic acid (Cox & Hickey, 2001).…”