Chapter 12 - Selected 1D, 2D, and 3D Experiments: A Further Look

Abstract

The ability to create and manipulate double quantum coherence (DQC) is an essential component in a number of 1D and 2D nuclear magnetic resonance (NMR) experiments. One can eliminate certain unwanted signals by choosing only coherence pathways that go through a p = ±2 step. The simple procedure is needed for a double quantum filter (DQF) and return to consideration of INADEQUATE, which depends on the use of a 13C DQF. INADEQUATE is designed to establish correlations between coupled 13C nuclei and thus elucidate the carbon framework of an organic molecule. DQC can be produced in a pair of coupled spins; in a 2D experiment, the DQC thus produced is allowed to evolve and is eventually converted to observable magnetization whereas in a 1D experiment the DQC is often converted almost immediately to observable magnetization. Some of the 2D experiments can be extended to three or four dimensions to provide additional correlations and to spread out the crowded 2D peaks that sometimes arise from large molecules.