Related Experiment Video
Updated: Aug 9, 2026
Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
Synthesis, structural characterization, and theoretical studies of complexes of magnesium and calcium with gallium
Cameron Jones1, David P Mills, Jamie A Platts
1Center for Fundamental and Applied Main Group Chemistry, School of Chemistry, Main Building, Cardiff University, Cardiff CF10 3AT, UK. jonesca6@cardiff.ac.uk
Abstract:
The magnesium- and calcium-gallium heterocycle complexes [Mg{Ga[(ArNCH)2]}2(THF)3] and [Ca{Ga[(ArNCR)2]}2(THF)4], R = H or Me, Ar = C6H3Pr(i)2-2,6, have been prepared via the reduction of [I2Ga{(ArNCR)2}] with the group 2 metal in tetrahydrofuran. The mechanisms of the reactions have been elucidated, and the crystal structures of the complexes exhibit the first structurally authenticated Ga-Mg and Ga-Ca bonds in molecular species. Theoretical studies suggest that the heterocycle-group 2 metal interactions have significant ionic character.
Related Concept Videos
02:42Valence Bond Theory
03:02Colors and Magnetism
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.
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...
01:23Properties of Organometallic Compounds
02:52Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
01:07Ladder Diagrams: Complexation Equilibria
The formation constant, K1, for the formation of Cd(NH3)2+ complex from cadmium and ammonia is 3.55 × 102. Log K1 (i.e. pNH3) is 2.55, and...