Poly[bis(1,3-dimethyl-1,3-diazinan-2-one)(2,5-dioxidoterephthalato)zirconium(IV)]

In the title coordination polymer, [Zr(C8H2O6)(C6H12N2O)2]n, the ZrIV atom, which lies on a crystallographic twofold rotation axis, is coordinated by two O,O′-bidentate 2,5-dioxidoterephthalate (DHTP4−) ligands and two O-bonded 1,3-dimethyl-1,3-diazinan-2-one (DMPU) ligands (the latter in a cis orientation) in a distorted ZrO6 octahedral geometry. The deprotonated hydroxy and carboxy O atoms of the DHTP4− ligand chelate the ZrIV ion via a six-membered ring; the dihedral angle between the carboxylate group and the aromatic ring is 19.94 (11)°. The DHTP4− ligand is completed by crystallographic inversion symmetry and coordinates to two ZrIV atoms, thereby forming polymeric zigzag chains propagating in the c-axis direction.

In the title coordination polymer, [Zr(C 8 H 2 O 6 )-(C 6 H 12 N 2 O) 2 ] n , the Zr IV atom, which lies on a crystallographic twofold rotation axis, is coordinated by two O,O 0 -bidentate 2,5-dioxidoterephthalate (DHTP 4À ) ligands and two Obonded 1,3-dimethyl-1,3-diazinan-2-one (DMPU) ligands (the latter in a cis orientation) in a distorted ZrO 6 octahedral geometry. The deprotonated hydroxy and carboxy O atoms of the DHTP 4À ligand chelate the Zr IV ion via a six-membered ring; the dihedral angle between the carboxylate group and the aromatic ring is 19.94 (11) . The DHTP 4À ligand is completed by crystallographic inversion symmetry and coordinates to two Zr IV atoms, thereby forming polymeric zigzag chains propagating in the c-axis direction.

Experimental
Zirconium(IV) chloride (0.047 g, 0.2 mmol) and 2,5-dihydroxyterephthalic acid (0.040 g, 0.2 mmol) were dissolved in 5 ml N,N′-dimethylpropylene urea (DMPU) in a Teflon liner of 23 ml volume under inert atmosphere in a glovebox. The teflon liner was sealed and put into a steel autoclave. The mixture was reacted for 3 d at 160°C. Reaction yielded a brown substance consisting of block shaped crystals and a white impurity. The product was collected by filtration, washed with DMPU and dried over night at room temperature in ambient atmosphere.

Refinement
Hydrogen atoms were placed geometrically in ideal positions and refined using a riding model, the U iso set to 1.5 times the thermal parameter of the carbon atom to which they are attached for methyl groups and 1.2 times for other hydrogen atoms.  The asymmetric unit of the title compound with 50% probability displacement ellipsoids. Hydrogen atoms are omitted for clarity.

Figure 2
Packing diagram of the title compound viewed along the b axis. Hydrogen atoms are omitted for clarity.

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.