Structure and NMR properties of the dinuclear complex di-μ-azido-κ(4) N (1):N (1)-bis­[(azido-κN)(pyridine-2-carboxamide-κ(2) N (1),O)zinc(II)]

The new diamagnetic complex, [Zn(2)(N(3))(4)(C(6)H(6)N(2)O)(2)] or [Zn(2)(pca)(2)(μ(1,1)-N(3))(2)(N(3))(2)] was synthesized using pyridine-2-carboxamide (pca) and azido ligands, and characterized using various techniques: IR spectroscopy and single-crystal X-ray diffraction in the solid state, and nuclear magnetic resonance (NMR) in solution. The mol­ecule is placed on an inversion centre in space group P [Image: see text]. The pca ligand chelates the metal centre via the pyridine N atom and the carbonyl O atom. One azido ligand bridges the two symmetry-related Zn(2+) cations in the end-on coordination mode, while the other independent azido anion occupies the fifth coordination site, as a terminal ligand. The resulting five-coordinate Zn centres have a coordination geometry inter­mediate between trigonal bipyramidal and square pyramidal. The behaviour of the title complex in DMSO solution suggests that it is a suitable NMR probe for similar or isostructural complexes including other transition-metal ions. The diamagnetic nature of the complex is reflected in similar (1)H and (13)C NMR chemical shifts for the free ligand pca as for the Zn complex.