Related Experiment Video
Updated: May 17, 2026
09:45
Modification and Functionalization of the Guanidine Group by Tailor-made Precursors
Published on: April 27, 2017
Guanidinium dioxidobis(picolinato-κ(2)N,O)(picolinato-κO)uranate(VI)
Vitalii I Mishkevich1, Mikhail S Grigoriev, Alexandre M Fedosseev
1A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospekt, 119071 Moscow, Russian Federation.
Acta Crystallographica. Section E, Structure Reports Online
|November 6, 2012
Summary
This study details the crystal structure of a novel uranyl compound, highlighting its unique coordination environment and hydrogen bonding network. The findings offer insights into uranyl coordination chemistry and crystal packing in related materials.
Area of Science:
- Inorganic Chemistry
- Crystallography
- Uranium Chemistry
Background:
- Uranyl compounds are critical in nuclear fuel cycles and environmental remediation.
- Understanding the coordination chemistry of uranyl ions is essential for designing new materials.
- Picolinate ligands offer versatile coordination modes for metal ions.
Purpose of the Study:
- To characterize the crystal structure of a novel uranyl picolinate compound.
- To elucidate the coordination environment and bonding in the uranyl complex.
- To investigate the intermolecular interactions, specifically hydrogen bonding, within the crystal lattice.
Main Methods:
- Single-crystal X-ray diffraction was employed to determine the molecular and crystal structure.
- Analysis of bond lengths, angles, and coordination geometry around the uranium center.
- Identification and analysis of hydrogen bonding networks (N-H···O and N-H···N) using crystallographic data.
Main Results:
- The compound features a uranyl group coordinated by three picolinate ligands, with a N(2)O(5) coordination sphere.
- The uranium(VI) atom exhibits a distorted pentagonal-bipyramidal geometry.
- Extensive N-H···O and N-H···N hydrogen bonds link the uranyl complexes and counterions into layered structures parallel to the ac plane.
Conclusions:
- The crystal structure reveals a unique coordination mode of picolinate ligands around the uranyl ion.
- The observed hydrogen bonding network plays a crucial role in stabilizing the layered crystal architecture.
- This study contributes to the understanding of uranyl coordination chemistry and solid-state structures.
Related Concept Videos
01:19Diazonium Group Substitution: –OH and –H
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...