Introductory Organic Chemistry Spectroscopy

Explore infrared spectroscopy to identify functional groups through vibrational modes and wave-number based absorption, using functional group and fingerprint regions to monitor reactions like alcohol to ketone.

Explore the absorption regions of functional groups in IR spectroscopy, including O–H, NH, C–H (sp3/sp2/sp), C–C and CN triple bonds, and carbonyl around 1700 cm-1, with intensity tied to polarity.

Explore how bond strength, hybridization, resonance, angular strain, and symmetry influence IR absorption frequency, using Hooke's law, bond order, s character, and dipole moment changes to explain IR activity.

Explore sample infrared spectra for alkanes, alkenes, alcohols, ketones, aldehydes, esters, amines, nitriles, and more, with focus on C-H stretching, C=O, O-H, and resonance effects.

Explore how nuclear magnetic resonance identifies molecular structure by showing how nuclei align in an external magnetic field, occupy alpha and beta states, and absorb radio-frequency photons to flip spins.

Explore how shielding determines absorbed frequency in NMR by examining red and blue hydrogens on carbons bonded to fluorine and chlorine, and how electron density governs the B effective.

Explore lower field (downfield) and higher field (upfield) absorptions in old NMR techniques. See how the external field adjusts Be effective for nuclei with different electron densities, illustrated by methanol.

Explore how hydrogen chemical shifts arise from shielding and deshielding, using TMS as a reference and ppm reporting, to predict H NMR signals across different environments.

Explore anisotropic effects on chemical shifts in benzene, alkenes, and alkynes, linking sp2 hybridization and pi-electron fields to deshielding and higher shifts (6.5–8, 4.5–6, and 2.5 ppm).

Link hydrogen counts to NMR peak areas by integrating distinct proton types; blue ~3.4 ppm, black ~2.4 ppm, red ~1.4 ppm, with peak areas matching hydrogen numbers.

Explore hydrogen NMR spin-spin splitting: black hydrogens show triplets, blue hydrogens show doublets from vicinal coupling. See how external magnetic fields and coupling constants create absorbed frequencies via B effective.

Explore how the n plus one rule predicts NMR signal splitting by vicinal hydrogens, enabling you to assign singlets, doublets, triplets, and other patterns.

Learn how coupling constants in hertz reveal molecular geometry by analyzing vicinal, geminal, and allylic couplings and typical j values for alkanes, alkenes, benzene rings, and meta positions.

Explore h nmr splitting patterns with the n plus one rule, identifying doublets, triplets, quartets, and septets; relate peak areas to hydrogen counts and j values for alkenes.

Analyze h-nmr spectra of isopropyl bromide and para nitrotoluene, apply the n+1 rule and vicinal coupling, and interpret deshielding and peak area ratios.

Explore how to decode complex splitting patterns in proton NMR using the n plus one times m plus one rule for vicinal hydrogens, illustrated by propyl bromide, toluene, and ethanol.

Identify carbon types with carbon-13 NMR, noting deshielded carbonyl carbons near 180 ppm and less deshielded sp3 carbons around 20–22 ppm, and that signals are not split.

Identify structures from mixed h-nmr and c-nmr spectra and calculate degrees of unsaturation using the given formula. Assign h and c signals, including benzene rings and carbonyl regions.

Calculate degrees of unsaturation and interpret h-nmr and c-nmr patterns to identify functional groups and proposed structures. Assign signals for ethyl, methyl, and benzene hydrogens, noting deshielding near carbonyls.