Question

what is anisotopic effect in nmr

Answer 1

The consequence of magnetic anisotropy effects is to provide a stereochemical component to the chemical shift of a nucleus: the chemical shift changes depending on the spacial relationship between a proton and nearby functional groups. Such effects can be valuable for making stereochemical assignments.

Answer 2

Anisotropic induced magnetic field effects are the result of a local induced magnetic field experienced by a nucleus resulting from circulating electrons that can either be paramagnetic when it is parallel to the applied field or diamagnetic when it is opposed to it.