Diastereomers & spectra

[blazinfury]

I know that diastereomers have different physical and chimerical properties. I was reading online that diastereomers can be distinguished from one another based on their spectra. I have a hard time understand this because don't diastereomers differ in a chiral center light polarization-- yet all the functional groups are exactly the same?

[Knumbnuts]

You are correct in saying they have different physical properties, isn't being able to be distinguished by their spectra using just that property?

The functional groups may be the same but they are arranged differently along a given carbon backbone. Therefore they are in different chemical and physical environments.

[blazinfury]

I don't really see what you are saying but let me clarify what I am confused about with an example. Lets say you have alpha and beta glucose which are epimers which are diastereomers on the anomeric carbon (C1). Isn't the spectra going to be the same for both of those molecules?

[Knumbnuts]

No, I would not expect them to be the same. In one case the H is axial, in the other equatorial. And it is in different magnetic environments. So different spectra.