The Ray–Dutt twist is a mechanism proposed for the
racemization
In chemistry, racemization is a conversion, by heat or by chemical reaction, of an optically active compound into a racemic (optically inactive) form. This creates a 1:1 molar ratio of enantiomers and is referred to as a racemic mixture (i.e. cont ...
of octahedral complexes containing three bidentate chelate rings. Such complexes typically adopt an
octahedral molecular geometry
In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The o ...
in their
ground state
The ground state of a quantum-mechanical system is its stationary state of lowest energy; the energy of the ground state is known as the zero-point energy of the system. An excited state is any state with energy greater than the ground state ...
s, in which case they possess
helical chirality
In chemistry, axial chirality is a special case of chirality in which a molecule contains two pairs of chemical groups in a non-planar arrangement about an axis of chirality so that the molecule is not superposable on its mirror image. The axis of ...
. The pathway entails formation of an intermediate of C
2v point group symmetry. An alternative pathway that also does not break any metal-ligand bonds is called the
Bailar twist. Both of these mechanism product complexes wherein the ligating atoms (X in the scheme) are arranged in an approximate trigonal prism.
This pathway is called the Ray–Dutt twist in honor of
Priyadaranjan Ray (not
Prafulla Chandra Ray) and N. K. Dutt,
inorganic chemists at the
Indian Association for the Cultivation of Science abbr. ''IACS'' who proposed this process.
''Indian Association for the Cultivation of Science: Annual Report for 2018-19''. 2019. p. 09.
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See also
* Pseudorotation
* Bailar twist
* Bartell mechanism
* Berry mechanism
The Berry mechanism, or Berry pseudorotation mechanism, is a type of vibration causing molecules of certain geometries to isomerization, isomerize by exchanging the two axial ligands (see the figure) for two of the equatorial ones. It is the most ...
* Fluxional molecule
In chemistry and molecular physics, fluxional (or non-rigid) molecules are molecules that undergo dynamics such that some or all of their atoms interchange between symmetry-equivalent positions. Because virtually all molecules are fluxional in som ...
* Indian Association for the Cultivation of Science (IACS)
References
Molecular geometry
Stereochemistry
Coordination chemistry
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