(BQ) Part 2 book "Essential practical NMR for organic chemistry" has contents: Further elucidation techniques, carbon-13 NMR spectroscopy, some of the other tools, some of the other nuclei, quantification, safety, software, problems. | P1: JYS c08 JWST025-Richards October 7, 2010 10:34 Printer: Yet to come 8 Further Elucidation Techniques – Part 2 Instrumental Techniques Much of the research in NMR spectroscopy has been in the fiel of devising new and improved techniques for extracting ever more information from samples. Nowadays, the plethora of available techniques can be daunting for the relative newcomer to NMR. In the following sections, we shall endeavour to guide you through the veritable forest of acronyms by describing the most important and useful techniques and demonstrate how they can be used to solve real-world problems. Before entering the forest, we would advise you to step back a moment and pause for thought. What information do you require? Is it just a case of an aid to an assignment question, or do you need to discriminate between two or more possible structures? It is important to select the right tool for the job, as some of the experiments we will consider later on can take a significan time to acquire. Doing so will enable you to work more efficientl and have greater confidenc in your handiwork. Many of these instrumental techniques have a two-dimensional (2-D) counterpart, which have their own advantages and disadvantages. Rather than treat 2-D spectroscopy as a separate issue, we will include it where appropriate, interleaving it with the corresponding 1-D method. 2-D spectroscopy should perhaps be viewed as an interpretational aid for 1-D spectroscopy, rather than an end itself. Spin Decoupling (Homonuclear, 1-D) This is probably the oldest of the instrumental techniques but it is still very useful even today. It enables the user to determine which signals in a spectrum are spin-coupled to each other. It can be an extremely useful aid to assignment and can in some cases, even be used to facilitate conformational studies. In practise, a powerful secondary radio frequency is centred on the signal of interest whilst the spectrum is reacquired. This causes
