ochem Flashcards
(20 cards)
structural isomerism
Compounds having the same molecular formula but different structures
conformational isomerism
a form of stereoisomerism in which the isomers can be interconverted just by rotations about formally single bonds.
There are three types of conformational isomers: rotamers, staggered conformers, and eclipsed conformers
paraffins
indicating hydrocarbons with the general formula CnH2n+2.
cycloparaffins
any of a series of saturated alicyclic hydrocarbons of the general formula Cn H2n, having a closed chain of three or more carbon atoms, Ex cyclohexane
cis-trans isomerism
pairs of molecules which have the same formula but whose functional groups are in different orientations in three-dimensional space
dienes based on the positions of the double bonds
Cumulated Diene: A cumulated diene has two successive double bonds on adjacent Carbon. They are also called Allene
Conjugated Diene: A conjugated diene has two conjugated double bonds separated by a single bond.
Isolated Diene: An isolated diene has two double bonds separated by two or more double bonds.
Aromatic compounds
chemical compounds that consist of conjugated planar ring systems accompanied by delocalized pi-electron clouds in place of individual alternating double and single bonds.
ex: toluene and benzene
Huckel’s rule
The Huckel 4n + 2 Pi Electron Rule
when the total number of pi electrons belonging to the molecule can be equated to the formula ‘4n + 2’ where n can be any integer with a positive value (including zero).
The carcinogenic effect
of aromatic hydrocarbons
Aromatic hydrocarbons, particularly polycyclic aromatic hydrocarbons (PAHs), have been associated with carcinogenic effects
DNA Damage leading to cancer
Molecular mechanism of vision
light enters the eye and hits a molecule called 11-cis-retinal that is located within a protein called rhodopsin
The absorption of light causes the 11-cis-retinal to undergo a structural change, or isomerization, converting it into all-trans-retinal
chiral molecules
a molecule that is nonsuperimposable on its mirror image
achiral molecules
A molecule or ion is achiral if it is superimposable, i.e. it can be superimposed on its mirror image
Optical activity
the ability of a chiral molecule to rotate the plane of plane-polairsed light
Constitutional isomers
molecules with the same molecular formula but different connectivity of atoms.
configuration
refers to the spatial arrangement of atoms that can only be changed by breaking bonds.
Enantiomers
are pairs of compounds with exactly the same connectivity but opposite three-dimensional shapes. Enantiomers are not the same as each other; one enantiomer cannot be superimposed on the other. Enantiomers are mirror images of each other.
diastereomers
two molecules which are stereoisomers (same molecular formula, same connectivity, different arrangement of atoms in space) but are not enantiomers. are not mirror images of each other and non-superimposable.
racemates
a racemic mixture or racemate one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt.
meso compound
an achiral compound that has chiral centers. A meso compound contains an internal plane of symmetry which makes it superimposable on its mirror image and is optically inactive although it contains two or more stereocenters
Resolution
is the separation of a racemic mixture into its respective enantiomers. Since enantiomers are identical, they must first be converted into diastereomers, which have different energies and are easy to separate.
