{4-Bromo-2-[(2-{(ethylsulfanyl)[(2-oxidobenzylidene-κO)amino-κN]methylidene}hydrazinylidene-κN 1)methyl]phenolato-κO}(ethanol-κO)dioxidouranium(VI)

In the title complex, [U(C17H14BrN3O2S)O2(C2H5OH)], the UVI cation has a distorted pentagonal–bipyramidal environment with the pentagonal plane defined by two N and two O atoms of the tetradentate Schiff base ligand and the O atom of the ethanol molecule. Two oxide O atoms occupy the axial positions. The azomethine C=N group and the Br atom are disordered over two positions in a 0.8356 (18):0.1644 (18) ratio. The ethylthiolyl group is disordered over three conformations in a 0.8356 (18):0.085 (6):0.079 (6) ratio, and the ethanol ligand is also disordered over three orientations in a 0.470 (16):0.277 (19):0.253 (18) ratio. In the crystal, molecules form centrosymmetric dimers through hydrogen bonding between ethanol O—H donors and phenolate O-atom acceptors. Weak C—H⋯O interactions consolidate the crystal packing.

In the title complex, [U(C 17 Table 1 Hydrogen-bond geometry (Å , ). of metal ions fitted for square planar coordination (e. g. VO(II), Cu(II), Ni(II), UO 2 (II)) can lead to tetradentate (N, N, O, O) complexes, Fig. 1 Following our interest in the synthesis and structural characterization of organic and metallorganic compounds containing heterocycles for applications as advanced materials and bioactive compounds (Centore, Ricciotti et al., 2012;Takjoo et al., 2011;Takjoo & Centore, 2013), and in the analysis of crystal structures controlled by the formation of H bonds (Centore et al., 2013), we report the structural investigation of the title compound, (I). (I) was obtained by the template reaction of 5-bromo-2-hydroxybenzaldehyde-S-ethylisothiosemicarbazone with salicylaldehyde, in the presence of uranyl acetate.
The molecular structure of (I) is shown in Fig. 2. The heptacoordination around the metal atom can be described as In the equatorial plane, two six-membered and one five-membered rings are formed involving the metal atom. The five membered ring is almost planar, while the two six-membered rings are in envelope conformation, with the metal atom out of the plane. The bite angles corresponding to the formation of the six-membered rings are slightly larger than the five membered ring.
Molecules of the title compound have H bonding donor and acceptor groups, and the crystal packing shows the formation of H bonds. In the crystal, molecules form centrosymmetric dimers through H bonding between O-H donors and phenolato Oacceptors, giving rise to ring patterns R 2 2 (8). The rings include the uranium atoms, Fig. 3. The same pattern is present in the crystals of a closely related compound (Takjoo et al., 2012). The oxygen atoms of the uranyl moiety are involved in weak H bonding interactions. In the case of O3, aromatic and imino C-H are the weak donors, and

Refinement
The H atom of the hydroxy group was located in difference map. All other H atoms were generated stereochemically and were refined by the riding model. For all H atoms U iso =1.2×U eq of the carrier atom was assumed (1.5 for methyl groups).
The crystal structure shows a remarkable degree of static disorder. In fact, molecules enter the crystal in two orientations of the tetradentate ligand, which are nearly obtained by rotation of 180° around the line joining U1 with the barycentre of N2A-C8A. There results a complete superposition of the atoms of the tetradentate ligand in the two orientations, with exception for bromine, sulfur and the methyl group of the S-ethyl tail. These atoms were found in difmaps and were refined. By refining also the occupancy factor, it resulted that the main orientation has an occupation factor higher by far than the other (0.836 (2) and 0.164 (2)). The resolved atoms of the low populated split positions were refined with some restraints on bond lengths and angles in order to keep the same geometry of the higher occupancy position (SAME instruction of SHELXL97). Also the ethanol molecule coordinated to uranyl is disordered over three positions. Since the methylene carbon atoms of the three different positions of the ethanol molecule are quite close to each other, they were refined with isotropic displacement parameters.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ.  (8)