Chapter 10C - Magnetic Resonance

• qualitative analysis • information about atom arrangement • interactions b/w matter and magnetic field/radiowaves • energy from radiowaves changes the spin of particles in nucleus.

• odd numbered nuclei (mass/atomic number) have spin & magnetic properties No magnetic field = nuclear spin of magnetic nuclei orientated randomly Magnetic field = nuclei adopt specific orientations

• with the magnetic field (lower energy state & more common) • against the magnetic field (higher energy state & less common)

• radiowaves of particular frequency passes through sample, energy is absorbed & nucleus flips from low to high energy state (spin-flip) • when nuclei flip back to low energy, energy is released • measured and recorded on spectrum as chemical shift

• type of nucleus • chemical environment surrounding nucleus (nuclei are shielded by electrons orbiting around them)

• chemical shift for given environment measured relative to reference compound • TMS is used (chemically inert & 1H/C environment) • peak found at 0ppm

• type of carbon environments • provides information about a carbon atom and its bonds to other atoms

no. of different or non-equivalent carbon environments

• x-axis • represents type of carbon environment in compound • scale: 0-250ppm

• different hydrogen environments • chemical shifts on a spectrum from 0-13ppm

• no. of proton environments • ratio of protons in each environment (area under the peak) • possible type of protons present in sample (chemical shift)

• includes peak splitting • no. of H on neighbouring carbon atom + 1 -OH and NH2 produce signlet & have no affects on neighbouring groups