[1-(2-Oxidobenzylidene)-4-phenylthiosemicarbazidato-κ3 O,N 1,S](pyridine-κN)copper(II)

In the structure of the title compound, [Cu(C14H11N3OS)(C5H5N)], the CuII atom exhibits a slightly distorted square-planar CuN2OS coordination polyhedron consisting of a phenyl O, an azomethine N and a thioamide S atom from the tridentate thiosemicarbazonate dianion, and the N atom of a pyridine molecule. The thiosemicarbazonate ligand exists in the thiol tautomeric form as an E isomer. Rotational disorder of the pyridine and phenyl rings in a 1:1 ratio of the respective components is observed. An extensive network of weak N—H⋯S, C—H⋯O, C—H⋯N and C—H⋯S hydrogen-bonding interactions consolidates the structure.

In the structure of the title compound, [Cu(C 14 H 11 N 3 OS)-(C 5 H 5 N)], the Cu II atom exhibits a slightly distorted squareplanar CuN 2 OS coordination polyhedron consisting of a phenyl O, an azomethine N and a thioamide S atom from the tridentate thiosemicarbazonate dianion, and the N atom of a pyridine molecule. The thiosemicarbazonate ligand exists in the thiol tautomeric form as an E isomer. Rotational disorder of the pyridine and phenyl rings in a 1:1 ratio of the respective components is observed. An extensive network of weak N-HÁ Á ÁS, C-HÁ Á ÁO, C-HÁ Á ÁN and C-HÁ Á ÁS hydrogenbonding interactions consolidates the structure.
The title compound crystallizes with one molecule in the asymmetric unit ( Fig. 1), which differs from the previously reported Ni compound (Cao et al., 2007) that crystallizes with two different molecules. The copper atom in the title structure exhibits a slightly distorted square-planar coordination with a mean deviation from the Cu1/O1/N1/S1/N4 plane of 0.0485 Å. The doubly deprotonated ligand molecule coordinates to the copper(II) atom in a tridentate manner via a phenyl oxygen, an azomethine nitrogen and a thioamide sulfur atom, creating five-and six-membered chelate metalla rings. The pyridine molecule completes the square-planar coordination environment of the Cu(II) atom. Values of Cu-O, Cu-N and Cu-S bond lengths are in a good agreement with related structures (Naik et al., 2003). The C8-S1 (1.749 (3) Å) and C8-N2 The title structure contains several planar fragments. The major part Cu1/O1/N1/N2/S1/C1-C9 (denoted as plane A) has a mean deviation from the least squares plane of 0.023 Å. The disordered phenyl ring contains two planar fragments C9/C10A/C11A/C12/C13A/C14A (plane B) and C9/C10B/C11B/C12/C13B/C14B (plane C) with a mean deviation from the corresponding least squares planes of 0.026 and 0.020 Å, respectively. The dihedral angles between planes A/B, A/C and B/C are 17.00 (19)°, 26.3 (2)° and 43.1 (3)°. The mean deviations from the least squares planes for the disordered pyridine ring N4/C15A/C16A/C17/C18A/C19A (plane D) and N4/C15B/C16B/C17/C18B/C19B (plane E) amount to 0.0054 and 0.0329 Å, respectively, with a dihedral angle between planes D and E of 51.2 (3)°.
The crystal packing of the title compound ( Fig. 2) is characterised by an alternating arrangement of disordered phenyl and pyridine rings in neighboring molecules (configuration A and B). An extensive network of weak N-H···S, C-H···O, C-H···N and C-H···S hydrogen bonding interactions additionally stabilizes the crystal structure (Table 2).
Experimental 20 ml (5x10 -3 M) of an aqueous solution of copper acetate was stirred in a cone flask for 2 hours with a mixture that contained 10 ml (10 -2 M) of an ethanolic solution of salicylaldehyde (4)-phenylthiosemicarbazone and 2 ml of pyridine.
The resulting solution was left for 3 days in a dark place. As a result, brown needle-like crystals of title compound were isolated from the solution.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 Rfactors(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.    (7) 169.