Dicylopentadienyl[4-(4-vinylbenzyloxy)pyridine-2,6-dicarboxylato]titanium(IV) monohydrate

The title compound, [Ti(C5H5)2(C16H11NO5)]·H2O, exhibits a titanocene unit coordinated to a styrene-substituted pyridine-2,6-dicarboxylate ligand synthesized for use as a monomer for polymerization or copolymerization yielding metallocene-containing polymers. The compound crystallized as a monohydrate and the solvent water molecule forms strong O—H⋯O hydrogen bonds with the carboxylate O atoms of the Ti complex, which play an important role in the connection of adjacent molecules. In addition, weak intermolecular C—H⋯O hydrogen bonds also contribute to the crystal packing arrangement.

The title compound, [Ti(C 5 H 5 ) 2 (C 16 H 11 NO 5 )]ÁH 2 O, exhibits a titanocene unit coordinated to a styrene-substituted pyridine-2,6-dicarboxylate ligand synthesized for use as a monomer for polymerization or copolymerization yielding metallocenecontaining polymers. The compound crystallized as a monohydrate and the solvent water molecule forms strong O-HÁ Á ÁO hydrogen bonds with the carboxylate O atoms of the Ti complex, which play an important role in the connection of adjacent molecules. In addition, weak intermolecular C-HÁ Á ÁO hydrogen bonds also contribute to the crystal packing arrangement.

Comment
Metallocene-based polymers have attracted considerable attention and research interest in the areas of catalysts, photosensitizers, heat resisting materials, anticancer medicines and optical materials because of their excellent properties such as a high dielectric constant, high thermal stability and special rheological (Caldwell et al., 2000;Peckham et al., 2001). A number of pyridinecarboxylic acid titanocene-containing complexes have been synthesized (Dalir Kheirollahi et al., 2005).
In the current contribution we would like to report the crystal structure of the title titanocene-containing complex, which also features a styrene functionality and might thus be polymerized or co-polymerized to yield metallocene-containing polymers. The compound crystallized as a monohydrate and the solvate water molecule forms strong O-H···O hydrogen bonds with the carboxylate O atoms of the Ti complex that play an important role in the connection of adjacent molecules ( Figure 2). The water molecules are hydrogen bonded towards two symmetry dependent uncoordinated carboxylate oxygen atoms (O2) in neighboring molecules, with two water molecules bridging between two carboxylate O atoms so as to form a quadrilateral ring, thus connecting the complexes into hydrogen bonded dimers (Table 1, Figure 2). In addition, weak intermolecular C-H···O hydrogen bonds also contribute to the crystal packing arrangement (Table 1).

Refinement
Carbon bound H atoms were positioned geometrically and refined in the riding model approximation with C-H = 0.95, 0.99 and 1.00 Å, and with U iso (H) = 1.2 U eq (C). The water H-atoms were located in a difference Fourier map and were refined isotropically.

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 > 2sigma(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