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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. The system most often studied for the cis effect is an octahedral complex M(CO) 5 X where X is the ligand that will labilize a CO ligand cis to it.
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.
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 ...
In inorganic chemistry, the trans effect is the increased lability of ligands that are trans to certain other ligands, which can thus be regarded as trans-directing ligands. . It is attributed to electronic effects and it is most notable in square planar complexes, although it can also be observed for octahedral complexes.
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 ...
That is, the unoccupied d orbitals of transition metals participate in bonding, which influences the colors they absorb in solution. In ligand field theory, the various d orbitals are affected differently when surrounded by a field of neighboring ligands and are raised or lowered in energy based on the strength of their interaction with the ...
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.
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.