Learner Resource 2 – Analysing a proton NMR spectrum Use the list of ‘golden rules’ below to help you analyse the proton NMR spectrum provided. Golden rules for analysing proton NMR spectra: 1. Look at the peaks in the spectrum. How many different proton environments are there? 2. Label each peak with a letter. 3. Write down the chemical shift value for each peak. 4. Use the Data Sheet to find possible structures for each peak. 5. Look at the splitting for each peak. Is it a singlet (no adjacent protons), doublet (one adjacent proton), triplet (two adjacent protons), quartet (three adjacent protons) or multiplet (complex combination of adjacent protons). Note that ‘adjacent’ means the protons are on the carbon ‘next door’. 6. Look at the integration value for each peak, if provided; this may be a ratio or a whole number. The relative integration values give you information about the number of protons in each environment. A whole number above 3 often means there are multiple equivalent environments. The proton NMR spectrum of 1,3-dioxane is shown below. 1,3-dioxane Identify the protons responsible for each peak and explain the splitting patterns. Peak label Chemical shift value / ppm Possible structure Number of peaks Splitting; how many adjacent protons? A B C OCR Resources: the small print OCR’s resources are provided to support the teaching of OCR specifications, but in no way constitute an endorsed teaching method that is required by the Board, and the decision to use them lies with the individual teacher. Whilst every effort is made to ensure the accuracy of the content, OCR cannot be held responsible for any errors or omissions within these resources. © OCR 2015 - This resource may be freely copied and distributed, as long as the OCR logo and this message remain intact and OCR is acknowledged as the originator of this work. OCR acknowledges the use of the following content: Please get in touch if you want to discuss the accessibility of resources we offer to support delivery of our qualifications: resources.feedback@ocr.org.uk Version 1 Identification of Unknowns 2 © OCR 2015