I've been racking my brain trying to get a grasp on how to use nMR to figure out compound structure. I have an exam coming up, and the instructor will be giving us the molecular formula, an Infared spectrum and an nMR spectrum to figure out the structure of a compound.
Three problems like this make up the bulk of the exam... which means if I don't learn it, I'm screwed, and I'm not going to lie to you, I'm really not enjoying this. It would really be helpfull if any of you can help me add to/modify my procedure..to make this as painless as possible, and so that I can just be over with it. I tried reading some things online, but they just don't seem to be doing it. Maybe it's because what I'm really looking for is more of a structured procedure (yeh, I know.. thats a no no in chem).
So far here's the plan of action I have made for each problem:
1. Calculate the DU (degrees of unsaturation), and use it with the molecular formula to write down some variations of what the compound may look like with double bonds or rings if apply
2. Look at IR for OH group (~3000ppm), Carbonyl groups - ketone (~1700-1800ppm), aldehyde (?). The prof. said we will primarily only be dealing with those functional groups. Then subtract the new info I get from the molecular formula.
3. Locate triplets, doublets, and singlets on nMR spectrum. So far what I know is that if I see 4 little cuts in a peak section, it means there are 3 hydrogens on neighboring carbons - but thats all I know! I don't know where to go from here. It's really frustrating!
Any help would be greatly appreciated.
Many thanks
Three problems like this make up the bulk of the exam... which means if I don't learn it, I'm screwed, and I'm not going to lie to you, I'm really not enjoying this. It would really be helpfull if any of you can help me add to/modify my procedure..to make this as painless as possible, and so that I can just be over with it. I tried reading some things online, but they just don't seem to be doing it. Maybe it's because what I'm really looking for is more of a structured procedure (yeh, I know.. thats a no no in chem).
So far here's the plan of action I have made for each problem:
1. Calculate the DU (degrees of unsaturation), and use it with the molecular formula to write down some variations of what the compound may look like with double bonds or rings if apply
2. Look at IR for OH group (~3000ppm), Carbonyl groups - ketone (~1700-1800ppm), aldehyde (?). The prof. said we will primarily only be dealing with those functional groups. Then subtract the new info I get from the molecular formula.
3. Locate triplets, doublets, and singlets on nMR spectrum. So far what I know is that if I see 4 little cuts in a peak section, it means there are 3 hydrogens on neighboring carbons - but thats all I know! I don't know where to go from here. It's really frustrating!
Any help would be greatly appreciated.
Many thanks
