anisotropic vs diastereotropic?

[thebillsfan]

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whats the difference?

 

[maverick09]

i'm guessing this was an answer choice on a practice test?

diastereotopicity is essentially when you substitute a atom/group/isotope, usually in the place of a hydrogen, and create a chiral center in the process (there also has to be a chiral center already in the molecule, hence the term diastereotopic). anyways, once the chiral center is created you have a set of diastereomers. This means that the two hydrogens originally on the atom where you subsituted are diastereotopic and thus have different chemical shifts

...and i have no idea what the other term is. maybe someone else will know

i hope they're not putting this on the MCAT these days....

 

[thebillsfan]

i'm guessing this was an answer choice on a practice test?

diastereotopicity is essentially when you substitute a atom/group/isotope, usually in the place of a hydrogen, and create a chiral center in the process (there also has to be a chiral center already in the molecule, hence the term diastereotopic). anyways, once the chiral center is created you have a set of diastereomers. This means that the two hydrogens originally on the atom where you subsituted are diastereotopic and thus have different chemical shifts

...and i have no idea what the other term is. maybe someone else will know

i hope they're not putting this on the MCAT these days....

mav, what youre talking about seems to me to be an example of a "prochiral" center. is that related to diastereomer?

and anisotropic is defined by wiki as "the property of being direction dependent... a difference in a physical property (absorbance, refractive index, density, etc.) for some material when measured along different axes. An example is the light coming through a polarizing lens."

This seems pretty close to diastereotopicity to me--the question I'm referring to has a cycilc molecular and a hydrogen above and below the molecule but on the same carbon. The question asked why the Hs on the same carbon have diff chemical shifts. I picked anisotropy without knowing what it meant (sort of stupid). it was wrong, but when i looked up anisotropy on wikipedia, the fact that it's "directionally dependent" and "different physical property on a different axis" seems like its also defining the phenomena of different chemical shifts above and below the plane of the molecule