What a learner can do afterwards
- Reads a COSY map to trace a chain of coupled protons
- Uses a one-bond correlation experiment to attach each proton to its own carbon
- Uses a long-range correlation experiment to join fragments across a quaternary carbon
- Assembles the evidence from several spectra into one assigned structure and states the weakest link in the argument
1 · Read
You already know a one-dimensional spectrum shows where signals sit. A two-dimensional experiment shows which signals are connected. Each spot off the diagonal links two signals, so you read relations instead of guessing them.
A COSY map traces chains of coupled protons. Start at one proton, follow its cross-spot to the neighbour, then to the next. Walking the spots walks the chain, proton by proton, through the fragment.
A one-bond map attaches each proton to its own carbon. Every spot pairs one proton with the carbon holding it, so each chain from the COSY walk gains its carbon skeleton. Now every proton knows its carbon.
A long-range map joins fragments across carbons with no protons, such as quaternary centres. Assemble all three maps into one structure, then name the weakest link: the correlation with the fewest supporting spots carries the least weight.
COSY walks the proton chains, the one-bond map adds carbons, and long-range spots bridge the silent centres.
2 · Watch
Take it off screen
Where it sits
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.