Bis(1,3-dimethyl-1,3-diazinan-2-one)dinitratodioxidouranium(VI)

Tomoya Suzuki; Takeshi Kawasaki; Yasuhisa Ikeda

doi:10.1107/S1600536810049883

. 2010 Dec 4;67(Pt 1):m18. doi: 10.1107/S1600536810049883

Bis(1,3-dimethyl-1,3-diazinan-2-one)dinitratodioxidouranium(VI)

Tomoya Suzuki ^a, Takeshi Kawasaki ^a, Yasuhisa Ikeda ^a,^*

PMCID: PMC3050256 PMID: 21522544

Abstract

The title compound, [U(NO₃)₂O₂(C₆H₁₂N₂O)₂], exhibits a hexagonal–bipyramidal geometry around the U^VI ion, which is situated on an inversion centre and coordinated by two oxide ligands in the axial positions, and four O atoms from two bidentate NO₃ ⁻ and two O atoms from two 1,3-dimethyl-1,3-diazinan-2-one (DMPU) ligands in the equatorial plane. These ligands are located in trans positions. The –(CH₂)₃– moiety in the DMPU ligand is disordered over two positions in a 0.786 (11):0.214 (11) ratio.

Related literature

For the structures of uranyl(VI) nitrate complexes, see: Alcock et al. (1990 ▶); Cao et al. (1993 ▶, 1999 ▶); Ikeda et al. (2004 ▶); Kannan et al. (2008 ▶); Koshino et al. (2005 ▶); Pennington et al. (1988 ▶); Takao et al. (2008 ▶); van Vuuren & van Rooyen (1988 ▶); Varga et al. (2003 ▶); Villiers et al. (2004 ▶).

Experimental

Crystal data

[U(NO₃)₂O₂(C₆H₁₂N₂O)₂]
M _r = 650.40
Triclinic,
a = 7.8529 (6) Å
b = 8.7706 (6) Å
c = 9.1990 (6) Å
α = 115.611 (2)°
β = 113.348 (2)°
γ = 91.041 (2)°
V = 510.62 (6) Å³
Z = 1
Mo Kα radiation
μ = 8.01 mm⁻¹
T = 173 K
0.17 × 0.13 × 0.12 mm

Data collection

Rigaku R-AXIS RAPID diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.343, T _max = 0.447
4800 measured reflections
2307 independent reflections
2306 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.017
wR(F ²) = 0.045
S = 1.06
2307 reflections
143 parameters
H-atom parameters constrained
Δρ_max = 0.88 e Å⁻³
Δρ_min = −0.93 e Å⁻³

Data collection: PROCESS-AUTO (Rigaku, 2006 ▶); cell refinement: PROCESS-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2006 ▶); program(s) used to solve structure: SIR92 (Altomare et al., 1994 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: CrystalMaker (CrystalMaker, 2007 ▶); software used to prepare material for publication: CrystalStructure.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810049883/kj2159sup1.cif

e-67-00m18-sup1.cif^{(16.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810049883/kj2159Isup2.hkl

e-67-00m18-Isup2.hkl^{(113.4KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

U1—O1	1.774 (2)
U1—O2	2.363 (2)
U1—O4	2.526 (2)
U1—O3	2.549 (2)

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Symmetry code: (i) Inline graphic .

Acknowledgments

We thank Dr Motoo Shiro of Rigaku Corporation for help with the structure solution.

supplementary crystallographic information

Comment

Crystal structures of various uranyl(VI) nitrate complexes with neutral unidentate ligands (L) have been reported. The uranyl(VI) nitrate complexes normally have a conformation of UO₂(NO₃)₂(L)₂ (Cao et al., 1999; Cao et al., 1993; Ikeda et al., 2004; Kannan et al., 2008; Koshino et al., 2005; Pennington et al., 1988; Takao, et al., 2008; van Vuuren & van Rooyen 1988; Varga et al., 2003; Villiers et al., 2004). The UO₂(NO₃)₂(L)₂ complexes exhibit hexagonal bipyramidal geometry, in which the U^VI atom is coordinated by two oxo ligands in the axial positions, and four oxygen atoms from two bidentate NO₃^- and two donating atoms from two L in the equatorial plane. These ligands are located in the trans positions. Recently, we have reported that N-cyclohexyl-2-pyrrolidone (NCP) can selectively precipitate uranyl(VI) species in HNO₃ aqueous solution and that the precipitate has an above typical molecular structure, i.e., UO₂(NO₃)₂(NCP)₂ (Ikeda et al., 2004; Varga et al., 2003). Similarly, we have also studied other N-alkyl-2-pyrrolidone (NRP) (Ikeda et al., 2004; Koshino et al., 2005; Takao et al., 2008; Varga et al., 2003), 2-pyrrolidone(NHP) (Ikeda et al., 2004) modification: 2-pyrrolidone(NHP) (Takao et al., 2008), and 1,3-dimethyl-imidazolidone (DMI) (Koshino et al., 2005). We report herein the synthesis and crystal characterization of the new uranyl(VI) complex UO₂(NO₃)₂(DMPU)₂ (I) (DMPU = 1,3-dimethyl-1,3-diazinan-2-one (N, N'-dimethylpropyleneurea)).

The molecular structure of the title complex is shown in Fig. 1. U1 has a hexagonal bipyramidal coordination geometry. The two uranyl oxo atoms (O1) from the uranyl(VI) ion occupy the axial position of U1, and two carbonyl oxygen atoms (O2) from the two unidentate DMPU and four oxygen atoms (two O3 and two O4) from the two bidentate NO₃^- are situated in the trans positions in the equatorial plane of U1 (Fig. 1). The selected parameters are listed in Table 1. These structural features are similar to those of uranyl(VI) nitrate complexes with NRPs (Ikeda et al., 2004; Koshino et al., 2005; Takao et al., 2008; Varga et al., 2003), 2-imidazolidone type ligands [1,3-dibutyl-imidazolidone (DBI) and DMI modification: 1,3-dibutyl-imidazolium (DBI) (Cao et al., 1999) and DMI (Koshino et al., 2005)] and tetramethylurea (TMU) (van Vuuren & van Rooyen, 1988). The U—O_carbo bond length of the title complex is slightly shorter than those of uranyl(VI) nitrate complexes with NHP [2.414 (3) Å] (Takao et al., 2008), N-cyclohexylmethyl-2- pyrrolidone [2.383 Å] (Koshino et al., 2005), N-(1-ethylpropyl)-2-pyrrolidone [2.372 (2) Å] (Takao et al., 2008), N-neopentyl-2-pyrrolidone [2.382 (3), 2.389 (3) Å] (Takao et al., 2008), and NRPs having alkyl chains of carbon number 2 ~4 (about 2.37 ~2.4 Å) (Ikeda et al., 2004; Koshino et al., 2005; Takao et al., 2008). On the other hand, The U—O_carbo bond of I is slightly longer than those of uranyl(VI) nitrate complexes with TMU [2.335 (3) Å] (van Vuuren & van Rooyen, 1988), urea [2.341 (5), 2,348 (5) Å] (Alcock et al., 1990), DBI [2.345 (3) Å] (Cao et al., 1999), and NCP [2.348 (2) Å] (Varga, et al., 2003; Ikeda et al., 2004). The differences in U—O bonds are considered to be due to those in donicity and size of L. In the dmpu ligand, C3 and C3B display disorder in a 0.786 (11) and 0.214 (11) occupancy ratio.

Experimental

Uranyl stock solution of 0.5 M (M = mol dm^-3) was prepared by dissolving UO₂(NO₃)₂^.6H₂O in 3 M HNO₃ aqueous solution. To 1 ml of the UO₂²⁺ solution was added 1 mmol of DMPU with vigorous stirring. Yellow precipitate was obtained. The resulting precipitate was filtered off, and washed with hexane. The precipitate was recrystallized from dichloromethane.