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In inorganic chemistry, the cis effect is defined as the labilization (or destabilization) of CO ligands that are cis to other ligands. CO is a well-known strong pi-accepting ligand in organometallic chemistry that will labilize in the cis position when adjacent to ligands due to steric and electronic effects.
For compounds with doubly bridging CO ligands, denoted μ 2-CO or often just μ-CO, the bond stretching frequency ν CO is usually shifted by 100–200 cm −1 to lower energy compared to the signatures of terminal CO, which are in the region 1800 cm −1. Bands for face-capping (μ 3) CO ligands appear at even lower energies. In addition to ...
Considering both weak and strong ligand fields, a Tanabe–Sugano diagram shows the energy splitting of the spectral terms with the increase of the ligand field strength. It is possible for us to understand how the energy of the different configuration states is distributed at certain ligand strengths.
Prussian blue is intensely blue owing to an intervalence charge transfer band. Intervalence charge transfer (IVCT) is a type of charge-transfer band that is associated with mixed-valence compounds. Unlike the usual MLCT or LMCT bands, the IVCT bands are lower in energy, usually in the visible or near-infrared region of the spectrum and is broad ...
A spectrochemical series is a list of ligands ordered by ligand "strength", and a list of metal ions based on oxidation number, group and element.For a metal ion, the ligands modify the difference in energy Δ between the d orbitals, called the ligand-field splitting parameter in ligand field theory, or the crystal-field splitting parameter in crystal field theory.
The greater stabilization that results from metal-to-ligand bonding is caused by the donation of negative charge away from the metal ion, towards the ligands. This allows the metal to accept the σ bonds more easily. The combination of ligand-to-metal σ-bonding and metal-to-ligand π-bonding is a synergic effect, as each enhances the other.
In cases where the ligand has low energy LUMO, such orbitals also participate in the bonding. The metal–ligand bond can be further stabilised by a formal donation of electron density back to the ligand in a process known as back-bonding. In this case a filled, central-atom-based orbital donates density into the LUMO of the (coordinated) ligand.
Mechanism proposed for Kumada coupling (L = Ligand, Ar = Aryl). In such cases, the mechanism generally involves reductive elimination of R-R' from L n MR(R') (L = spectator ligand). This intermediate L n MR(R') is formed in a two-step process from a low valence precursor L n M. The oxidative addition of an organic halide (RX) to L n M gives L n ...