Structure determination of two metal-organic complexes from high-resolution synchrotron powder diffraction data

Area of Science:

• Inorganic Chemistry
• Crystallography
• Materials Science

Background:

• Rhodium and cobalt complexes are crucial in catalysis and materials science.
• Understanding their precise crystal structures is key to predicting and controlling their properties.
• Previous literature reported different findings for neutral rhodium complexes.

Purpose of the Study:

• To determine the crystal structures of two novel organometallic compounds: [1,2-bis(2,6-diisopropylphenylimino)acenaphthene-N,N']carbonylchlororhodium(I) (1) and [N,N'-ethylene-bis(3-methylsalicylideneiminato)-O,N,N',O'](tetrahydrofurfuryl)-cobalt(II) (2).
• To characterize compound 1 as the first neutral rhodium complex with a bidentate nitrogen ligand.
• To establish the first three-dimensional structure of a tetrahydrofurfurylcobalt(III) complex.

Main Methods:

• High-resolution synchrotron X-ray powder diffraction data acquisition.
• Grid-search and Rietveld refinement techniques for structure determination and refinement.
• Application of soft restraints during Rietveld refinement for accurate structural analysis.

Main Results:

• The crystal structure of compound 1 was determined, revealing an orthorhombic system (space group Pbca, Z=8).
• The crystal structure of compound 2 was determined, showing a monoclinic system (space group P2(1)/n, Z=4).
• Refinement converged with R(p) values of 8.4% and 8.5% for compounds 1 and 2, respectively.

Conclusions:

• The study successfully elucidated the crystal structures of two unique rhodium and cobalt complexes.
• Compound 1 represents a significant finding as the first neutral rhodium complex featuring a bidentate nitrogen ligand.
• Compound 2 provides the first detailed 3D structural insight into tetrahydrofurfurylcobalt complexes.