Search results
Results From The WOW.Com Content Network
The magnitude of Δ o is determined by the field-strength of the ligand: strong field ligands, by definition, increase Δ o more than weak field ligands. Ligands can now be sorted according to the magnitude of Δ o (see the table below). This ordering of ligands is almost invariable for all metal ions and is called spectrochemical series.
Download as PDF; Printable version ... isothiocyanate is a weak-field ligand. Two examples are the ... and isothiocyanate ligands. Examples are found for heavy ...
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.
In contrast to O-bonded phosphine oxide ligands, the P-bonded phosphine oxides are strong field ligands. These ligands, which tend to engage in intramolecular hydrogen bonds. Illustrative is the complex derived from dimethylphosphine oxide , PtH(PMe 2 OH) 2 (PMe 2 O) (Me = CH 3 ).
The spectrochemical series is an empirically-derived list of ligands ordered by the size of the splitting Δ that they produce. It can be seen that the low-field ligands are all π-donors (such as I −), the high field ligands are π-acceptors (such as CN − and CO), and ligands such as H 2 O and NH 3, which are neither, are in the middle.
Halides are X-type ligands in coordination chemistry. They are both σ- and π-donors. Chloride is commonly found as both a terminal ligand and a bridging ligand. The halide ligands are weak field ligands. Due to a smaller crystal field splitting energy, the homoleptic halide complexes of the first transition series are all high spin.
Many ligands other than CO are strong "backbonders". Nitric oxide is an even stronger π-acceptor than CO and ν NO is a diagnostic tool in metal–nitrosyl chemistry. Isocyanides, RNC, are another class of ligands that are capable of π-backbonding.
For this reason, few examples exist of complexes containing both CO and N 2 ligand. Transition metal-dinitrogen complexes can contain more than one N 2 as "end-on" ligands, such as mer-[Mo(N 2) 3 (PPr n 2 Ph) 3], which has octahedral geometry. [15] In another example, the dinitrogen ligand in Mo(N 2) 2 (Ph 2 PCH 2 CH 2 PPh 2) 2 can be reduced ...