Crystal structure of calcium trans-N-(nitrilotriacetato)(pyridine-2-carboxylato)cobaltate(III) hexahydrate, Ca[Co(Nta)(Pic)]2] · 6H2O

Abstract

Crystals of Ca[CoIII (Nta)(Pic)]2 · 6H2O (I) (where Nta3− and Pic− are the nitrilotriacetate and picolinate ions, respectively) are prepared and characterized by the X-ray diffraction technique. Crystals I are monoclinic, a = 18.599(4) A, b = 12.556(3) A, c = 14.042(3) A, β = 102.90(3)°, V = 3196(1) A3, Z = 4, space group P21/c, R1 = 0.0278, wR2 = 0.0716, and Goof = 1.054 for 4982 reflections with I > 2σ(I). Structure I is built of the { Ca(H2O)4[Co(Nta)(Pic)]2{ 1∞ polymer ribbons and molecules of crystallization water. One of the two symmetrically independent anionic complexes (B) is included in the chain and alternates with cationic units, whereas the other anionic complex (A) forms a branch of this chain. The cationic and anionic units are interlinked via the interactions of the Ca2+ cations with the carbonyl atoms of the main (Nta3−) and additional (Pic−1) ligands. The octahedral environment of the Co(III) atoms consists of donor atoms of the Nta3− (N + 3O) and Pic− (N + O) ligands. The coordination polyhedron of the Ca atom (pentagonal bipyramid) includes two carbonyl O atoms of two Nta3− ligands, one OPic atom, and four Ow atoms of water molecules.