Related Experiment Video
Updated: Oct 19, 2025
Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyltroponeiron
Published on: August 12, 2019
Synthesis and characterization of trigonal bipyramidal FeIII complexes and their solution behavior
Adriana Lugosan1, Sophi R Todtz1, Andrew Alcázar1
1Department of Chemistry & Biochemistry, Loyola University Chicago, Flanner Hall, 1068 W Sheridan Rd, Chicago, IL 60660, United States.
Abstract:
A series of air-stable trigonal bipyramidal FeIII complexes supported by a redox non-innocent NNN pincer ligand, Cz (PyrR)2 - (R = iPr, Me, or H), were synthesized, fully characterized, and utilized for the investigation of the interaction between acetone and the FeIII center. The magnetic moments determined from the paramagnetic 1H NMR spectra in conjunction with EPR and Mössbauer spectroscopy indicate the presence of a high-spin ferric center. Cyclic voltammetry studies feature two quasi-reversible events corresponding to a metal-centered FeIII/II reduction around -0.40 V (vs. Fc) and a ligand-centered Cz (PyrR)2/Cz (PyrR)2 •+ oxidation at potentials near +0.70 V (vs. Fc). UV-Visible spectroscopy in CH2Cl2 showcases ligand-metal charge transfer (LMCT) bands, as well as coordination of acetone to Cz (PyrH)2FeCl2. In situ IR spectroscopy and solution conductivity (κ) measurements of Cz (PyrR)2FeCl2 with varied equivalents of acetone reveal that acetone is weakly associated with the iron center.
More Related Videos
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...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
03:45Formation of Complex Ions
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
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...