Crystal structure of μ-peroxido-κ4 O 1,O 2:O 1′,O 2′-bis[(nitrato-κO)(2,2′:6′,2′′-terpyridine-κ3 N,N′,N′′)dioxidouranium(VI)]

In the title dimeric complex, [{UO2(NO3)(C15H11N3)}2O2], a peroxide ion bridges the two uranyl(VI) [O=U=O]2+ ions. The O—O bond length of the peroxide is 1.485 (6) Å and the mid-point of this bond is located at the inversion centre of the dimer. The U atom exhibits a distorted hexagonal–bipyramidal coordination geometry with two uranyl(VI) O atoms occupying the axial positions and one O atom of the monodentate nitrate ion, both O atoms of the peroxide ion and the three N atoms of the chelating tridentate 2,2′:6′,2′′-terpyridine (terpy) ligand in the equatorial positions. Two of the N atoms of the terpy ligand lie above and below the mean plane containing the equatorial ligand atoms and the U atom [deviations from the mean plane: maximum 0.500 (2), minimum −0.472 (2) and r.m.s. = 0.2910 Å]. The dihedral angle between the terpy ligand and the mean plane is 35.61 (7)°. The bond lengths around the U atom decrease in the order U—N > U—Onitrate > U—Operoxo > U=O. The dimeric complexes pack in a three-dimensional network held together by weak π–π interactions [centroid–centroid distance = 3.659 (3) Å] between pyridyl rings of the terpy ligands in neighbouring dimers, together with intermolecular C—H⋯O and C—H⋯π interactions. Weak intramolecular C—H⋯O interactions are also observed.


)(C 15 H 11 N 3 )} 2 O 2 ], a peroxide ion bridges the two uranyl(VI) [O U O] 2+ ions.
The O-O bond length of the peroxide is 1.485 (6) Å and the mid-point of this bond is located at the inversion centre of the dimer. The U atom exhibits a distorted hexagonal-bipyramidal coordination geometry with two uranyl(VI) O atoms occupying the axial positions and one O atom of the monodentate nitrate ion, both O atoms of the peroxide ion and the three N atoms of the chelating tridentate 2,2 0 :6 0 ,2 00terpyridine (terpy) ligand in the equatorial positions. Two of the N atoms of the terpy ligand lie above and below the mean plane containing the equatorial ligand atoms and the U atom [deviations from the mean plane: maximum 0.500 (2), minimum À0.472 (2) and r.m.s. = 0.2910 Å ]. The dihedral angle between the terpy ligand and the mean plane is 35.61 (7) . The bond lengths around the U atom decrease in the order U-N > U-O nitrate > U-O peroxo > U O. The dimeric complexes pack in a three-dimensional network held together by weakinteractions [centroid-centroid distance = 3.659 (3) Å ] between pyridyl rings of the terpy ligands in neighbouring dimers, together with intermolecular C-HÁ Á ÁO and C-HÁ Á Á interactions. Weak intramolecular C-HÁ Á ÁO interactions are also observed.

terpyridine-κ 3 N,N′,N′′)dioxidouranium(VI)]
Takeshi Kawasaki and Takafumi Kitazawa S1. Experimental 10 ml of a methanolic solution containing 0.5 mmol of terpy was added to 10 ml of a methanolic solution containing 0.5 mmol of UO 2 (NO 3 ) 2 ·6H 2 O contained in a glass sample vial. The vial w as sealed with a lid and kept in sunlight at room temperature. Yellow crystals grew after one day. The crystal structure of the yellow material has not yet been determined.
After about two months, orange crystals of the title complex were obtained.

S2. Refinement
All H atoms were placed at calculated positions, with C(CH)-H = 0.95 Å and allowed to ride on the parent atoms, with U iso (H) = 1.2U eq (C). The (1 0 0) reflection, affected by the beamstop, was omitted from the final refinement.

Figure 1
Structure where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 2.24 e Å −3 Δρ min = −1.57 e Å −3 Special details Experimental. face-indexed absorption correction carried out with XPREP (Bruker, 2007) 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.