IIT JEE , AIEEE Forum - Chemistry , Organic Chemistry

Taara

i got to know that there can be organic cpds that are optically active and yet DON"T have a chiral center. how come they r optically active . eg of such compounds.

any other info...

pls help!!!

paddy.dude

is that possible.............r u sure.........

ashish_banga

some molecules are chiral without having any asymmetric (carbon) atoms ? their chirality is due to their shape.

ashish_banga

Common examples include 1,1'-bi-2-naphthol (BINOL) and 1,3-dichloro-allene, which have axial chirality, and (E)-cyclooctene, which has planar chirality.

RATE ME

ashish_banga

sahilgupta_iit

that's because they have stereocentre. remember all chiral centres are stereocentres but NOT vice-versa

sahilgupta_iit

also molecules having no plane or centre of symmetry are optically active, as seen in example given by ashish_banga

rohanrony

therre are some comps lke that

this is bcoz alrhough the compounds dont have a chiral c atom ,
the mirror image of the com[pound is not super-imposable

1 example -

sandeepramesh

yes substituted biphenyls are examples.

dream

the main condition for optical activity is that the compd shud be unsymmetrical

it may or may not possess a chiral centre
examples are allenes, biphenyl, etc

ramkumar_november

here is another information

allenes with even number of carbon atoms attached to the cumulative double bond exhibit optical isomerism

odd number of carbon atoms means geometrical isomerism....

SPIRANES are optically active even though they dont possess chiral atom......

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