Nuclear Magnetic Resonance (NMR) Concepts

These flashcards cover key concepts related to Nuclear Magnetic Resonance (NMR), including signal characteristics, chemical shifts, and specific functional groups in regard to 1H and 13C NMR.

Incompletely resolved signals

NMR signals that are not fully distinguishable due to proximity of multiple signals.

Chemical shift

The change in the resonance frequency of a nucleus relative to a standard.

Deshielded

A term describing nuclei that experience reduced electron density, leading to an upfield shift in NMR.

Methylene protons

Protons attached to a methylene group (-CH2-), which are generally more deshielded than methyl protons.

Quaternary carbons

Carbon atoms bonded to four other carbons, which do not show NMR signals in the 13C NMR spectrum.

Carbonyls

Organic functional groups characterized by a carbon atom double-bonded to an oxygen atom, seen in 13C NMR.

Upfield

A direction in NMR indicating lower chemical shift values, often associated with higher shielding.