Aqua(azido)[N-(pyridin-2-ylcarbonyl)pyridine-2-carboxamido-κ3 N,N′,N′′]copper(II)

The title compound, [Cu(C12H8N3O2)(N3)(H2O)], was formed by the air oxidation of 2-(aminomethyl)pyridine in 95% ethanol in the presence of copper(II) nitrate and sodium azide with condensation of the resulting picolinamide molecules to generate the imide moiety. The CuII ion has a square-pyramidal coordination sphere, the basal plane being occupied by four N atoms [two pyridine (py) N atoms, the imide N atom and an azide N atom] in a nearly planar array [mean deviation = 0.048 (6) Å] with the CuII ion displaced slightly from the plane [0.167 (5) Å] toward the fifth ligand. The apical position is occupied by a coordinating water molecule [Cu—O = 2.319 (4) Å]. The crystal structure is stabilized by hydrogen-bonding interactions between the water molecules and carbonyl O atoms. The inversion-related square-pyramidal complex molecules pack base-to-base with long Cu⋯Npy contact distances of 3.537 (9) Å, preventing coordination of a sixth ligand.


Experimental
Crystal data [Cu(C 12

Comment
We are interested in the design and synthesis of Cu II complexes to study magnetostructural relationships in lowdimensional magnetic lattics (Landee and Turnbull, 2013). In this work, a wide variety of heterocyclic amines such as substituted pyrazine and pyridine compounds have been employed both as ligands and as bases. One such compound has been 2-aminomethylpyridine (Bruda et al., 2006). We were attempting the preparation of a series of Cu II complexes employing the 2-aminomethylpyridine molecule as a blocking agent to limit coordination by other species when we encountered the Cu II catalyzed air-oxidation and condensation of 2-aminomethylpyridine and resulting in situ formation of a Cu II nitrate complex of N-(pridin-2-ylcarboyl)pyridine-2-carbamide (bis-picolinimide; bpa) . A similar reaction, in the presence of azide ion, has shown the same oxidation and condensation resulting in the preparation of [(N-(pyridin-2-ylcarboyl)pyridine2-carboxamido)(azido)(aqua)copper(II)] (1).
Crystals of (1) (Figure 1) were produced via slow crystallization in air of an ethanolic solution of Cu(NO 3 ) 2 ·3H 2 O, 2aminomethylpyridine and sodium azide. The Cu II ion is coordinated by one bpa anion, one azide anion and a water molecule to generate a nearly square pyramidal, five-coordinate structure. The basal plane is composed of three nitrogen atoms from the bpa ligand and the coordinated azide ion. The four N-atoms are planar within 0.048 (6) Å and the Cu II ion is displaced 0.167 (5) Å out of this plane. The O-atom of the water molecule is located in the apical position [Cu-O = 2.319 (4)Å]. The Addison parameter is 0.053, indicating that the geometry is very close to square pyramidal (Addison et al., 1984).

Experimental
Cu(NO 3 ) 2 .3H 2 O, ethanol and NaN 3 were obtained from VWR Scientific while 2-aminomethylpyridine was purchased from Aldrich Chemical. All were used as received.

Refinement
All H-atoms bound to carbon were placed in calculated positions (C-H = 0.95 Å) and refined using a riding model with U iso =1.2U eq (C). Hydrogen atoms bonded to oxygen atoms were located in the difference map and their positions allowed to refine using anti-bumping restraints (0.85 Å for O-H distances) and fixed isotropic U values [U iso =1.2U eq (O)].

Crystal data
[Cu (C 12  Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.