lecture 5: chirality Flashcards
BLANK objects are nonsuperimposable mirror images
chiral objects
blank objetcs are mirror images which are superimposable
achiral objects
what are chiral objecst
non superimposable mirror images
what are achiral objects
mirror images which are superimposable
give example of chiral objects
hands, ears, feet
give examples of achiral objects
cup, chair, pencil
what are constitutional isomers
same mol formula diff connectivity
what are stereoisomers
same connectivity same molcular formula but different arrangements of atoms in 3d space
same connectivtiy but different 3d isomers
what are the 2 catergoes of steroisomers
enantiomers
diasteriomers
what are enantiomers
stereoisomers that are NON superimposable mirror images
what are diasteriomets
stereosiomers that are non-superimposabl, none mirror images
which are stereoisomers that are NON superimposable mirror images
enamtiomers
which are stereosiomers that are non-superimposabl, none mirror images
diastomeriomers
a chiral compound and its mirror image is a diastereomer or enenatiomer
enantiomer
true or false: enantimoers can only occur for chiral molucles
true
what are isomers
same mol formula but diff compound
what is an assymetric center
c bound to 4 diff substituents
isomers with assymetric centers are what shape
tetrahedral
cis trans isomers refer to spatial orietnance about what
about a double bond or a ring
true or false: enantiomer is a non superimposable mirror image
true
true or false: enantiomers are trigonal planar with 3 diff groups
false, they are tetrahydral with 4 diff groupes resulting in 2 possible configurations
cis trans isomers are non superimposable non mirror images, therefore that makes them what type of isomer
diastermioer
what is a chiral center
a tetrahedral carbon bonded to 4 different groups (sp3 hybridized)
changing conf requires what
breaking bonds
changing comformation requires what
rotating bonds
true or false: molcuels with only 1 chiral center are chiral
true
compounds with one chiral center exist as two different steroisomrs called…
enantiomers
true or false: a chiral center is not always possible for a single tetrahedral atoom (sp3 hybrid) with 4 diff cgroups attached
false
what is a stereogenic center
any atom at which the interchange of two groups produced a stereoisomer
true or false; all sterocenters are chiral centers
false (ex: sp2 carbons)
what is the biological imporatnt of chirality
body can distinguish between enantiomers (specific bonding sites) and is only favouranble in 1 way
true or false: a compound can still be chiral with an internal plane of symmetry
false, it will not be chiral it is possese an internal plane of symmetry
what are the 4 steps for naming enantiomers (chiral center)
1) each group is assignmend priority according to atmic number
2) if two identical, next bond is looked at (double bond coutns as two)
3) orient molcule so that low priority is in the back
4) trance clock (r) or CCW (S)
true or false: chiral molecules have no optical activtiy
false, they do
what molecules are optically inactive
achiral
what are the conditions for something to be optically activtiy
1) must be chrial
2) one enatiomer must be present in excess (or just cancel each otehr out)
what do enantiomers do to polar plane light
cause equal rotation of the plane of polarixation but in opposive directions
if something is + that means it does what to light
rotates it CW
if something is - that does what to light
rotates it CCW
what happens if you have exactly the same amount of enatiomers are use plane polarized loght
since there are equal concentrations, you will get a racemic mixture and it will be optically inacvity (cancel each other out)
does something need to be optically pure solution to have optical acivtiy
no as long as one of the enantiomers is in excess
what is an optically pure solition
a solution containing one 1 enantioner
true or false: reaction of 2 achiral molcules leadss to an achiral molecule
false, can sometimes lead to chiral products
what is the formula for finding all thepossible configurations for molecules with 2 chiral centers
2 ^ n where n is number of chiral centers
what is the trick for finding different chiral compunds with 2 chriality
RR
SS
RS
SR
(flip both simul, flip one side, flip other)
=always keep ones on the chain the same
true or false: enantiomers are mirror images of each other
true
true or false: enatimiors have opposite and unequal rotation of polarized light
false, equal
do aenatiomers have same or diff physical properties
same
are diasteriomers mirror images of each other
no
what is the relationship between diasteriomers are polarized light?
no direct correleation
do diasteriomers have same or diff physical properties
very diff
true or false: a strucuter with 2 chriality centers always has 4 isomers
false, sometimes only has three because of meso compounds
are all molecules with chriral centers considered chiral compounds
no they can be achoral
