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A classic example of a polydentate ligand is the hexadentate chelating agent EDTA, which is able to bond through six sites, completely surrounding some metals. The number of times a polydentate ligand binds to a metal centre is symbolized by " κ n ", where n indicates the number of sites by which a ligand attaches to a metal.
Chelation (/ k iː ˈ l eɪ ʃ ən /) is a type of bonding of ions and their molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom.
In coordination chemistry, denticity (from Latin dentis 'tooth') refers to the number of donor groups in a given ligand that bind to the central metal atom in a coordination complex. [1] [2] In many cases, only one atom in the ligand binds to the metal, so the denticity equals one, and the ligand is said to be unidentate or monodentate.
In chemistry, linkage isomerism or ambidentate isomerism is a form of structural isomerism in which certain coordination compounds have the same composition but differ in which atom of the ligand is bonded to the metal. Typical ligands that give rise to linkage isomers are: cyanide, CN − – isocyanide, NC −; cyanate, OCN − – isocyanate ...
In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from Latin ligare, which means 'to bind'. In protein-ligand binding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein.
This ligand–metal–ligand geometric parameter is used to classify chelating ligands, including those in organometallic complexes. It is most often discussed in terms of catalysis , as changes in bite angle can affect not just the activity and selectivity of a catalytic reaction but even allow alternative reaction pathways to become accessible.
Ambident dienophile 57 reacts with DAPC 54 at the cyclobutene π-bond to produce ligand 58; in contrast, the related ambident dienophile 59 reacts with DAPC 54 at the naphthoquinone π-center to produce adduct 60 (lack of shielding of the methylene protons supports the stereochemical assignment).
EDDHA or ethylenediamine-N,N ′-bis(2-hydroxyphenylacetic acid) is a chelating agent. Like EDTA, it binds metal ions as a hexadentate ligand, using two amines, two phenolate centers, and two carboxylates as the six binding sites. The complexes are typically anionic. The ligand itself is a white, water-soluble powder.