Synthesis and structure of Catena-[bis(2-methylimidazole)(mu-phthalato)cobaltate(II)]

A new coordination compound [Co(Pht)(2-MeIm)(2)] (I), where Pht(2-) is the deprotonated radical of o-phthalic acid (H(2)Pht) and 2-MeIm is 2-methylimi dazole, was synthesized. Its structure was established using X-ray diffract ion analysis. The crystal is orthorhombic: space group Pca2(1), a= 15.350(3 ), b = 7.957(2), c = 13.997(3) Angstrom, rho (calcd.) = 1.505 g/cm(3), and Z = 4. The tetrahedral coordination of the Co(II) atom includes two N atoms of two 2-methylimidazole molecules and two oxygen atoms of two carboxyl gr oups from different acid radicals. The Co-N distances are equal to 2.022(2) and 2.031(2) Angstrom, while the Co-O distances are 1.972(2) and 2.000(2) Angstrom. The carboxyl groups of the Pht(2-) radical and the aromatic nucle us form angles of 47.2 degrees and 35.9 degrees, whereas the angle formed b y the carboxyl groups themselves is 50.3 degrees. Compound I is a polymer, which is confirmed by the 1,6-bridging function of the o-phthalic acid radi cal. The Co . . . Co distance in a chain is equal to 7.367 Angstrom. Separa te chains are united in the crystal into a framework via N-H . . .O hydroge n bonds.