Poly[aqua{μ3-5-[(pyridin-2-ylmethyl)amino]isophthalato-κ5 N,N′:O 1,O 1′:O 3}cobalt(II)]

In the title polymer, {[Co(C14H10N2O4)(H2O)]·3.5H2O}n, the Co2+ ion is coordinated by three carboxylate O atoms from two 5-[(pyridin-2-ylmethyl)amino]isophthalate anions, two N atoms from a (pyridin-2-ylmethyl)amino group and an O atom from a water molecule, furnishing a distorted CoO4N2 octahedral geometry. Each anion acts as a μ3-bridge, linking cobalt ions into a two-dimensional layer parallel to (100). The asymmetric unit also contains three and a half solvent water molecules, which could not be modeled. Therefore, the diffraction contribution of the solvent water molecules was removed by the subroutine SQUEEZE in PLATON [Spek (2009). Acta Cryst. D65, 148–155]. The crystal structure is stabilized by O—H⋯O hydrogen bonds in which the coordinated water molecule acts as donor and the carboxylate O atoms as acceptors.

In the title polymer, {[Co(C 14 H 10 N 2 O 4 )(H 2 O)]Á3.5H 2 O} n , the Co 2+ ion is coordinated by three carboxylate O atoms from two 5-[(pyridin-2-ylmethyl)amino]isophthalate anions, two N atoms from a (pyridin-2-ylmethyl)amino group and an O atom from a water molecule, furnishing a distorted CoO 4 N 2 octahedral geometry. Each anion acts as a 3 -bridge, linking cobalt ions into a two-dimensional layer parallel to (100). The asymmetric unit also contains three and a half solvent water molecules, which could not be modeled. Therefore, the diffraction contribution of the solvent water molecules was removed by the subroutine SQUEEZE in PLATON [Spek (2009). Acta Cryst. D65, [148][149][150][151][152][153][154][155]. The crystal structure is stabilized by O-HÁ Á ÁO hydrogen bonds in which the coordinated water molecule acts as donor and the carboxylate O atoms as acceptors.

Table 2
Hydrogen-bond geometry (Å , ). Comment 5-(Pyridin-2-ylmethyl)aminoisophthalic acid possesses some peculiar features in the assembly of coordination compounds due to its unique molecular structure. Herein, we report the crystal structure of the title complex. The asymmetric unit consists of one cobalt ion, one 5-(pyridin-2-ylmethyl)aminoisophthalate anion, one coordinated water molecule, and 3.5 lattice water molecules. However, the solvent water molecules could not be modeled as discrete atomic sites. We employed SQUEEZE subroutine in PLATON (Spek, 2009) to exclude the diffraction contribution of the solvent water molecules.
In the title polymer, each Co ion is coordinated by three carboxylate O atoms from two different 5-(pyridin-2ylmethyl)aminoisophthalate anions, two N atoms from (pyridin-2-ylmethyl)amino group and one O atom from a coordinated water molecule, to furnish a distorted CoO 4 N 2 octahedral geometry ( Fig. 1). Each anion acts as a µ 3 -bridge, linking cobalt ions to form a two-dimensional layer. In the crystal structure, there exist O-H···O hydrogen bonds (Table 1). Coordinated water molecule and carboxylate oxygen atoms act as donors or acceptors in the formation of these hydrogen bonding interactions.

Experimental
A mixture of cobalt nitrate hexahydrate (58.2 mg, 0.2 mmol), 5-(pyridin-2-ylmethyl)aminoisophthalic acid (54.4 mg, 0.2 mmol), and 3 ml N,N-dimethylformamide in H 2 O (12 ml) was sealed in a 16 ml Teflon-lined stainless steel container and heated to 373 K for 3 days. After cooling the container to the room temperature, red block crystals of the title complex were obtained.

Refinement
The hydrogen atoms bonded to C atoms were included in geometrically idealized positions and constrained to ride on their parent atoms, with C-H = 0.93 and 0.97 Å for aryl and methylene H-atoms with U iso (H) = 1.2U eq (C). The hydrogen atoms bonded to N1 and O5 were located from a difference Fourier map and fixed at those positions with U iso (H) = 1.2U eq (N or O)].
The structure contains three and a half molecules of water of hydration, which could not be modeled as discrete atomic sites. We employed SQUEEZE in PLATON (Spek, 2009) to remove the diffraction contribution of the solvent water molecules. Fig. 1. : The coordination environment of Co ion in the title complex with the ellipsoids drawn at the 30% probability level. The hydrogen atoms have been omitted for clarity. Symmetry codes: A = -x + 2, -y + 1, -z + 1; B = x, -y + 1/2, z -1/2; C = x, -y + 1/2, z + 1/2.

Figures
Crystal data [Co(C 14