Guanidinium dioxidobis(picolinato-κ2 N,O)(picolinato-κO)uranate(VI)

Vitalii I Mishkevich; Mikhail S Grigoriev; Alexandre M Fedosseev; Philippe Moisy

doi:10.1107/S1600536812035465

. 2012 Sep 5;68(Pt 10):m1243. doi: 10.1107/S1600536812035465

Guanidinium dioxidobis(picolinato-κ² N,O)(picolinato-κO)uranate(VI)

Vitalii I Mishkevich ^a,^*, Mikhail S Grigoriev ^a, Alexandre M Fedosseev ^a, Philippe Moisy ^b

PMCID: PMC3470132 PMID: 23125576

Abstract

In the title compound, (CH₆N₃)[U(C₆H₄NO₂)₃O₂], the uranyl group is coordinated by two O and two N atoms from two chelating picolinate ligands, and one O atom from a third picolinate ligand. The coordination environment of the U^VI atom (N₂O₅) is distorted pentagonal–bipyramidal. In the crystal, all amino groups are involved in the formation of N—H⋯O and N—H⋯N hydrogen bonds, which link cations and anions into layers parallel to the ac plane.

Related literature

For the disordered crystal structure of a related complex without guanidinium in which the uranyl ion is chelated by two picolinato ligands and coordinated via the O atom of a picolinic acid molecule, see: Grechishnikova et al. (2007 ▶).

Experimental

Crystal data

(CH₆N₃)[U(C₆H₄NO₂)₃O₂]
M _r = 696.42
Orthorhombic,
a = 16.3842 (4) Å
b = 13.1678 (3) Å
c = 21.2743 (4) Å
V = 4589.80 (18) Å³
Z = 8
Mo Kα radiation
μ = 7.13 mm⁻¹
T = 293 K
0.18 × 0.06 × 0.04 mm

Data collection

Bruker Kappa APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2007 ▶) T _min = 0.360, T _max = 0.764
77357 measured reflections
6604 independent reflections
3818 reflections with I > 2σ(I)
R _int = 0.093

Refinement

R[F ² > 2σ(F ²)] = 0.035
wR(F ²) = 0.075
S = 1.01
6604 reflections
307 parameters
H-atom parameters constrained
Δρ_max = 1.07 e Å⁻³
Δρ_min = −0.71 e Å⁻³

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT-Plus (Bruker, 1998 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812035465/cv5297sup1.cif

e-68-m1243-sup1.cif^{(27.8KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812035465/cv5297Isup2.hkl

e-68-m1243-Isup2.hkl^{(323.3KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N11—H11A⋯O4ⁱ	0.86	2.02	2.859 (6)	166
N11—H11B⋯O6ⁱⁱ	0.86	2.12	2.918 (6)	154
N12—H12A⋯O3ⁱ	0.86	2.18	3.033 (6)	169
N12—H12B⋯N3	0.86	2.24	3.042 (7)	156
N13—H13B⋯O8	0.86	2.10	2.847 (6)	146
N13—H13C⋯O6ⁱⁱ	0.86	2.35	3.083 (6)	144

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank the CEA (RSTB/RBPCH, France) for financial support.

supplementary crystallographic information

Comment

The title structure contains complex anions, in which dioxidocations UO₂²⁺ are surrounded by two bidentate-chelating picolinate anions, coordinated by N and O atoms with the formation of 5-membered cycles, and one monodentate picolinate anion, coordinated by an O atom of the carboxylic group (Fig. 1). The guanidinium cation is located in the outer sphere. The UO₂ groups are almost linear and symmetric. Coordination polyhedra of U atoms are distorted pentagonal bipyramids. The main distortions of coordination polyhedra are the differences between O—U—O and O—U—N angles in the equatorial plane. The U—O distances for O atoms of monodentate picolinate ligands are shorter, compared to U—O distances for bidentate ligands. The U—N distances are longer than U—O ones. Guanidinium cations act as proton donors for 6 H-bonds (2 bonds from each amino group) (Table 1) with O atoms of carboxylic groups and N atoms of organic anions. Each cation is connected to three complex anions forming layers parallel to the (010) plane (Fig. 2). This compound is the first anionic picolinate complex of uranyl and the first example of monodentate coordination of picolinate anion to an actinide cation.

Experimental

The solid UO₃.H₂O was dissolved in 0.5 M aqueous solution of picolinic acid at 1:2 molar ratio. Then an equimolar quantity of guanidinium picolinate solution was added. This solution had been prepared by the neutralization of 1 M aqueous solution of guanidinium carbonate by an equimolar quantity of solid picolinic acid.

Light-yellow crystals were obtained by heating the reaction mixture up to 120 °C in a sealed glass tube.