Ligands: Co-ordination Compounds, Chemistry, NEET

Ligand

A ligand is an ion or molecule that binds to a central metal atom to form a coordination compound. It can be an anion or a neutral molecule that donates a pair of electrons to the metal.

Monodentate Ligand

Monodentate ligands are ligands that bind to the central metal atom through a single point of attachment, usually donating one pair of electrons.

Bidentate Ligand

Bidentate ligands can form two bonds with the central metal ion, as they have two donor atoms that can delocalize electron pairs.

Polydentate Ligand

Polydentate ligands are ligands with multiple donor sites that can attach to a metal ion simultaneously, known as a chelate effect.

Chelate

A chelate is a complex formed between a central metal atom and a polydentate ligand, resulting in a ring structure.

Ambidentate Ligand

Ambidentate ligands can bind through different atoms, but only one atom is attached at a time, such as the ligand nitrite which can coordinate through nitrogen or oxygen.

Denticity

Denticity refers to the number of donor sites a ligand uses to bind to a central metal ion.

Hexadentate Ligand

A hexadentate ligand is capable of forming six bonds with a central metal atom, such as EDTA.

Chelating Agent

A chelating agent is a compound that can form several bonds to a single metal ion, enhancing the stability of the coordination compound.

Cyclic Ligands

Cyclic ligands are structured in a ring form that enables them to bind effectively with the metal atom in a coordination complex.

Macrocyclic Ligands

Macrocyclic ligands are large ring-shaped ligands with multiple donor atoms, capable of forming stable complexes with metal ions.

Isomeric Neutral Ligands

Isomeric neutral ligands are structural isomers that present variations in attachment points within a ligand molecule.

Null Ligand

A null ligand is a conceptual linear series in the context of coordination chemistry to denote potential spaces for ligands that are vacant or inactive in the coordination sphere.

Spectator Ligands

Spectator ligands are ligands that remain bound to the metal center without participating directly in reactions the complex undergoes, allowing for selective reactivity at other sites.

Pseudo Halo Ligands

Pseudo halo ligands are ligands which mimic the lone pair electron donation characteristics of halides but are not true halide ions.

Labelling of Ligands

Labelling of ligands involves identifying and describing the particular atom or location within a ligand involved in the bonding to the metal ion.

Saturated Ligands

Saturated ligands are those which, by virtue of strong sigma bonding, do not allow further coordination or pi interactions without disrupting existing bonds.

Functionalized Ligands

Functionalized ligands contain additional functional groups allowing for further complex formation or reactivity enhancement in coordination compounds.

Pi-back Bonding

Pi-back bonding refers to the process where ligands donate electron density back into d-orbitals of the central metal through pi interactions, essential for tuning ligand field strengths.

Tetra Dentate Ligand

A tetradentate ligand is a ligand that forms four bonds with a central metal ion, often producing stable chelate rings.

Cage Ligand

Cage ligands form three-dimensional molecular cavities around the metal ion, providing unique steric and electronic environments.

Fluorescent Ligands

Fluorescent ligands are those which can emit visible light upon excitation, used in monitoring biological and chemical systems.

Chirality in Ligands

Chirality in ligands involves the arrangement of atoms in a nonsuperimposable form on its mirror image, often leading to different responses in biological environments.