Related Experiment Video
Updated: Apr 23, 2026

ARL Spectral Fitting as an Application to Augment Spectral Data via Franck-Condon Lineshape Analysis and Color Analysis
Published on: August 19, 2021
Probing the photophysical capability of mono and bis(cyclometallated) Fe(ii) polypyridine complexes using inexpensive
1Laboratoire de Chimie et Physique Quantiques, UMR 5626 CNRS/Université Paul Sabatier, Toulouse, France. isabelle.dixon@irsamc.ups-tlse.fr.
Abstract:
The abundance and low toxicity of iron with respect to ruthenium would certainly make it valuable for photophysical applications if one could circumvent its tendency to make high-spin compounds and the kinetic lability of its polypyridine complexes, both related to the presence of low-lying quintet metal-centered excited states. The aim of this study was to probe the photophysical potential of six cyclometallated Fe(ii) polypyridine complexes by means of ground state DFT and TDDFT calculations. Quantitative and qualitative indicators were extracted from such calculations and bring us to the conclusion that two complexes should display promising photophysical properties: Fe(NCN)(NNC) and Fe(NNC)2.
Related Concept Videos
Colors 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...
Crystal 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...
Valence Bond Theory
Crystal 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...
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group...
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation

