optical isomerism Flashcards
what does the dashed lines mean
going away from the paper backwards
what does the wedge mean?
bond coming towards the reader
what does the normal lines in bond angles?
bonds in the plane of paper
what are enantiomers?
stereoisomers that are non-superimposable mirror images of one another
they are identical in all their physiochemical properties other than their ability to rotate plane of plane polarised light which is equal in magnitude but opposite direction
Enantiomers – are stereoisomers related as an object to its
mirror image which is non-superimposable.
what is a chiral centre?
4 diferent groups attached to it
what is the clockwise rotation of plane polarised light to the right called ?
dextrorotatory +
what is the anticlockwise rotation of plane polarised light to the left called?
levorotatory (-)
what is a RACEMIC MIXTURE?
equal parts of mixture with both enantiomers
what are the 3 types of different forms of chiral molecules?
-detrorotaory isomer (+)
-laevorotatory isomer (-)
-racemic mixture (equal parts of both above and DO NOT rotate plane polarised light)
what does R AND S MEAN?
Rectus = to the right (clockwise) +
Sinister = to the left
(anticlockwise) -
so if Nh2 was on the left of a chiral carbon of serine how would you write it
S-Serine
how do you name based on R AND S?
- find groups and rank form highest to lowest priority (atomic number) in chiral carbon
- find if it goes clockwise R
or anticlockwise S
how do you name them as S or R if there is a number inbetween them ?
just find the next number for example if it is 1 then 4 then 2 go straight to 2 and skip 4 then count if it is clockwise or anticlockwise
what are Fischer Projection?
flat projection of tetrahedral
WHAT ARE DIASTERIOISOMERS?
stereoisomers which are NOT enantiomeric which differ in they physiochemical properties
