1. 1D and 2D NMR techniques are described. 1D NMR involves applying a 90 degree pulse to a sample in a magnetic field and measuring the resulting signal. 2D NMR applies two 90 degree pulses separated by a short delay and measures two signals, which are Fourier transformed to provide frequency information in two dimensions.
2. 2D NMR was first proposed by Jean Jeener and provides more structural information than 1D NMR as it plots data on two frequency axes rather than one. It involves collecting a series of 1D NMR spectra with varying pulse delays and further Fourier transforming these signals.
3. The document provides details on the principles, pulse sequences, and names of 1D and 2D NMR techniques.