List of Ligands and Charges PDF Free Download

List of Ligands and Charges PDF Download Info

List of Ligands and Charges PDF Free Download, classification of ligands pdf, en ligand charge, cn ligand charge.

Ligands in inorganic chemistry

   In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. Ligands are typically viewed as Lewis bases, although rare cases may involve Lewis acidic “ligands.” The reactivity of the central atom is dictated by ligand substitution rates, ligand reactivity, and redox. Ligand selection is critical in various practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemistry. Ligands are classified based on charge, size, coordinating atom identity, and electron donation.

   The composition of coordination complexes has been known since the early 1800s, with Alfred Werner’s work reconciling formulas and isomers. The splitting parameter, Δo, is the energy difference between the two sets of d-orbitals. Ligands can be sorted according to the magnitude of Δo. In complexes with a tetrahedral surrounding, d-orbitals split into two sets: low energy (dz2 and dx2−y2) and high energy (dxy, dxz and dyz). The energy difference between these two sets is called Δt, which is smaller than Δo. The arrangement of d-orbitals on the central atom significantly affects the properties of the resulting complexes. The absorption of light by electrons in orbitals with significant 3 d-orbital character can be correlated to the ground state of the metal complex, reflecting the bonding properties of the ligands. The relative change in d-orbital energy is described in Tanabe-Sugano diagrams.

   In low energy LUMO, such orbitals participate in bonding. The metal-ligand bond can be stabilized by back-bonding, where a filled, central-atom-based orbital donates electron density back to the ligand.

List of Ligands and Charges

Ligand motifs

   Ambidentate ligands can attach to the central atom in one of two or more places, giving rise to linkage isomerism. Bridging ligands link two or more metal centers, and most inorganic solids are coordination polymers. Binucleating ligands bind two metal ions, often featuring bridging ligands or donor groups that bind to only one of the two metal ions. Metal-ligand multiple bond ligands can bond to a metal center through the same atom but with a different number of lone pairs. Spectator ligands are tightly coordinating polydentate ligands that do not participate in chemical reactions but remove active sites on a metal. Bulky ligands are also involved in coordination. Bulky ligands control the steric properties of a metal center, impacting catalyst selectivity and stabilizing unusual coordination sites. They are also used to simulate steric protection provided by proteins to metal-containing active sites. Chiral ligands induce asymmetry within the coordination sphere and are used in homogeneous catalysis. Hemilable ligands contain at least two electronically different coordinating groups, increasing catalyst reactivity. Non-innocent ligands bond with metals in an unclear electron density distribution, often involving multiple resonance forms.

Common ligands

   Molecules and ions can be ligands for metals, with monodentate ligands including anions and simple Lewis bases. Anionic ligands include halides and pseudohalides, while charge-neutral ligands include ammonia, carbon monoxide, and water. Simple organic species are also common. Metals can bind to σ bonds in silanes, hydrocarbons, and dihydrogen. In complexes of non-innocent ligands, ligands are bonded via conventional bonds but are also redox-active. The strength of ligands changes when binding in alternative modes or when conformation is distorted.

Types of Ligands and their Examples

   Ligands are atoms, molecules, or ions with non-bonded electrons attached to a central transitional metal atom through coordinate bonds to form a coordination complex. They are classified based on their denticity, which is the number of bites or bonds from the ligand to the central atom. Monodentate ligands share one lone pair of their donor atom to a central electron-deficient atom in coordination compounds. They are further classified into negative ligands, neutral ligands, special monodentate ligands, abidentate ligands, and polydentate ligands (chelate ligands).

   Chelate ligands are more stable than simple complexes due to their chelating effect. Bidentate ligands have two donor atoms, allowing them to bind with the same central metal atom through two different donor atoms. Multiidentate or polydentate ligands, also known as chelate-forming ligands, are ligands that can bind with central metal atoms with multiple donor atoms. They form closed ring-like structures and are more stable than simple complexes due to the chelating effect. Ligands are classified into two types: biidentate ligands, which have two donor atoms, and cyclic or ring ligands, which have cyclic structures with multiple lone pairs available for donation. These ligands are more stable than noncyclic complexes when formed with metal atoms.

   Crystal Field Theory (CFT) describes the electronic structure of coordinated complex compounds, with ligands divided into two main categories based on their field. Strong field ligands cause great repulsion when approaching the central metal atom, making them good Lewis bases. They cause less repulsion, forming coordination compounds with low wavelength colors and less splitting energy.

List of Ligands and Charges PDF Free Download