Related topics: cells · organic molecules

Understanding how autoactivation triggers cell death

Apoptosis is a process that causes cell death. It can go awry in cancer cells, sustaining the disease. Scientists at St. Jude Children's Research Hospital have captured the structure of BAK, a protein that triggers apoptosis. ...

New route to the synthesis of P-chiral compounds

Chiral phosphines are one of the most commonly used ligands in assymetric metal catalysis for the synthesis of various useful drugs and pharmaceuticals. Have you ever wondered how to obtain them? Most of the so-called chiral ...

Predicting phosphine reactivity with one simple metric

Phosphines are among the most important ligands for transition metal catalysis. Phosphines bind to a metal and modify its structure, reactivity, and selectivity. Many of the most practiced catalytic reactions in the pharmaceutical/commodity ...

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Ligand

In coordination chemistry, a ligand is an ion or molecule (see also: functional group) that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from covalent to ionic. Furthermore, the metal-ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known involving Lewis acidic "ligands."

Metal and metalloids are bound to ligands in virtually all circumstances, although gaseous "naked" metal ions can be generated in high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection is a critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemistry.

Ligands are classified in many ways: their charge, their size (bulk), the identity of the coordinating atom(s), and the number of electrons donated to the metal (denticity or hapticity). The size of a ligand is indicated by its cone angle.

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