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3-Methylpentane is a branched alkane with the molecular formula C 6 H 14. It is a structural isomer of hexane composed of a methyl group bonded to the third carbon atom in a pentane chain. It is of similar structure to the isomeric 2-methylpentane , which has the methyl group located on the second carbon of the pentane chain.
Chiral molecules are always dissymmetric (lacking S n) but not always asymmetric (lacking all symmetry elements except the trivial identity). Asymmetric molecules are always chiral. [6] The following table shows some examples of chiral and achiral molecules, with the Schoenflies notation of the point group of the molecule.
Instead, both effects can also occur when the propagation direction of the electromagnetic wave together with the structure of an (achiral) material form a chiral experimental arrangement. [10] [11] This case, where the mutual arrangement of achiral components forms a chiral (experimental) arrangement, is known as extrinsic chirality. [12] [13]
The optical center is the middle carbon of the pentane backbone, which is connected to one hydrogen atom, one methyl group, one ethyl group – C 2 H 5, and one isopropyl group – CH(CH 3) 2. The two enantiomers are denoted (3R)-2,3-dimethylpentane and (3S)-2,3-dimethylpentane (the other simplest chiral alkane is its structural isomer 3 ...
Branched alkanes can be chiral. For example, 3-methylhexane and its higher homologues are chiral due to their stereogenic center at carbon atom number 3. The above list only includes differences of connectivity, not stereochemistry. In addition to the alkane isomers, the chain of carbon atoms may form one or more rings.
The achiral groups contain also transformations of determinant −1. In an achiral group, the orientation-preserving transformations form a (chiral) subgroup of index 2. Finite Coxeter groups or reflection groups are those point groups that are generated purely by a set of reflectional mirrors passing through the same point.
In stereochemistry, prochiral molecules are those that can be converted from achiral to chiral in a single step. [1] [2] An achiral species which can be converted to a chiral in two steps is called proprochiral. [2] If two identical substituents are attached to an sp 3-hybridized atom, the descriptors pro-R and pro-S are used to distinguish ...
The racemization occurs by way of an intermediate enol form in which the former stereocenter becomes planar and hence achiral. [14]: 373 An incoming group can approach from either side of the plane, so there is an equal probability that protonation back to the chiral ketone will produce either an R or an S form, resulting in a racemate.