Crystal structure of poly[bis-μ3-[(2-(1,2,4-triazol-1-yl)acetato-κ3 O:O':N)]- cobalt(II), [Co(C4H4N3O2)2]n, C8H8CoN6O4

Abstract

Source of materialAsolution of 2-(1H-1,2,4-triazol-1-yl)acetic acid (0.2 mmol) in 5 mL of H 2 Owas adjusted to pH 5with 1mol×L -1 NaOH solution, and Co(NO 3 ) 2 ×6H 2 O( 0.1 mmol) was added with stirring. The mixture was added to a10mLglass-tube, and this was sealed and heated to 130°C for 3days and then cooled to room temperature. The purple prism-shaped crystals were collected from the mother liquor. IR data (cm -1 ): 3160m, 1600s, 1520m,1 410m, 1320m, 1278m,1130m, 1030m,984w, 941w, 814w, 706m,683m, 586m. DiscussionRecently, the design, synthesis and characterization of coordination polymers have drawn great interest not only because of their versatile structural motifs and intriguing topological structures, but also due to their various potential applications as functional materials in the areas of optics, magnetism, electronics, catalysis, molecular recognition and adsorption and biological activity [1][2][3][4].The ligands and metal centers both are the key to the design and construction of metal-organic frameworks with fascinating topology and physicochemical properties. Al arge number of mononuclear,o ligonuclear,a nd polynucleart ransitionmetal complexes of 1-and 4-substituted 1,2,4-triazole derivatives have been synthesized and characterized [5][6][7][8]. On the other hand, because of the diversity of the coordination modes and high structural stability, carboxylate ligands are frequently used for the construction of MOFs [9][10][11]. In this paper, we select 2-(1,2,4-triazol-1-yl)acetate (tza)toreactwith Co(II)ions to obtainanew MOF. The asymmetric unit of the titlecomplexconsists of one half Co 2+ ion, and one 2-(1,2,4-triazol-1-yl)acetate (tza)a nion. TheCoatom is coordinated by four oxygen and two nitrogen donors from six tza ligands. The coordination figure shows distorted octahedral geometry. The bond lengths and angles around the Co(II) are in the ranges of 2.0891(16)-2.1584(2) Åa nd 84.83(7)°-180.00(5)°, respectively, which is in the normalrange for octahedral Co complexes. The carboxylate shows abidentate bridging mode and coordinates two Co(II) atoms. The triazole exhibits amonodentate mode and links to another Co(II) atom. The Co-Co distances through tza ligand are 4.8374(5), 7.8018(7) and 7.8018(7)Å, respectively. Consequently, each tza connects three Co(II) atomsa nd extend to form a( 3,6)-connected CdCl 2 -type two-dimensional network.