Search results
Results From The WOW.Com Content Network
The ligands end up with electrons in their π * molecular orbital, so the corresponding π bond within the ligand weakens. The other form of coordination π bonding is ligand-to-metal bonding. This situation arises when the π-symmetry p or π orbitals on the ligands are filled.
Ligand field molecular orbital (MO) bonding regimes for Werner-type (left), covalent (middle), and inverted ligand fields. [1] At the transition-metal - main group boundary, metal cations in organometallic complexes are more electronegative than the relatively more electropositive ligand atoms which act as z-type ligands.
In general, 'hard' metal ions prefer weak field ligands, whereas 'soft' metal ions prefer strong field ligands. According to the molecular orbital theory, the HOMO (Highest Occupied Molecular Orbital) of the ligand should have an energy that overlaps with the LUMO (Lowest Unoccupied Molecular Orbital) of the metal preferential.
Molecular orbital theory was seen as a competitor to valence bond theory in the 1930s, before it was realized that the two methods are closely related and that when extended they become equivalent. Molecular orbital theory is used to interpret ultraviolet–visible spectroscopy (UV–VIS). Changes to the electronic structure of molecules can be ...
Compounds that obey the 18-electron rule are typically "exchange inert". Examples include [Co(NH 3) 6]Cl 3, Mo(CO) 6, and [Fe(CN) 6] 4−.In such cases, in general ligand exchange occurs via dissociative substitution mechanisms, wherein the rate of reaction is determined by the rate of dissociation of a ligand.
The p-orbitals oriented in the z-direction (p z) can overlap end-on forming a bonding (symmetrical) σ orbital and an antibonding σ* molecular orbital. In contrast to the sigma 1s MO's, the σ 2p has some non-bonding electron density at either side of the nuclei and the σ* 2p has some electron density between the nuclei.
[12] [27] Namely the atomic s and p orbital(s) are combined to give four sp i 3 = 1 ⁄ √ 4 (s + √ 3 p i) orbitals, three sp i 2 = 1 ⁄ √ 3 (s + √ 2 p i) orbitals, or two sp i = 1 ⁄ √ 2 (s + p i) orbitals. These combinations are chosen to satisfy two conditions. First, the total amount of s and p orbital contributions must be ...
In chemistry, the trigonal prismatic molecular geometry describes the shape of compounds where six atoms, groups of atoms, or ligands are arranged around a central atom, defining the vertices of a triangular prism. The structure commonly occurs for d 0, d 1 and d 2 transition metal complexes with covalently-bound ligands and small charge ...