Organic Chemistry: Spectroscopy Master Class

Learn to spot alcohols in spectra by a broad, strong O-H stretch around 2600–3200 cm^-1 and a strong C-O stretch near 1100 cm^-1, with exploration of the fingerprint region.

Discover how to differentiate carboxylic acids from alcohols using IR spectroscopy, focusing on the broad O-H stretch and the diagnostic carbonyl peak around 1728 cm-1.

Compare and contrast the infrared spectra of alcohols and carboxylic acids, noting the broad carboxylic O-H stretch and the carbonyl peak near 1720 cm-1 that signals acids.

Compare carboxylic acids and esters by analyzing diagnostic peaks in spectra, including the broad O–H stretch and carbonyl band near 1750 cm⁻¹, to distinguish these groups.

Compare esters and ethers using their spectra, using the diagnostic carbonyl peak around 1750 cm-1 to distinguish them, and confirm with carbon–oxygen stretches near 1100 cm-1 in the fingerprint region.

Learn to differentiate ketones from alkenes by analyzing overlapping carbonyl and C=C stretches in IR spectra, then use the sp2 C–H stretch around 3100 cm-1 to confirm.

Learn to distinguish primary, secondary, and tertiary amines by nitrogen–hydrogen stretches in infrared spectra, by counting carbon groups attached to nitrogen, and by characteristic two, one, or no peaks.

Reveal aldehydes by the carbonyl peak near 1720 cm-1 and the aldehyde C-H stretches around 2900 cm-1, plus a diagnostic 28/27 hundred cm-1 doublet that differentiates from ketones and esters.

Master the theory and practice of mass spectrometry and spectroscopy. Learn how charged ions reveal molecular weight and distinguish brominated from chlorinated compounds using M over Z values.

Demonstrate how mass spectrometry uses electron bombardment to form the molecular ion, M+1, and base peak, using propane and carbon-12 and carbon-13 isotopes to explain isotope effects.

Explore how electron movement governs fragmentation, using single electron processes for bonds with low electronegativity differences (homiletic cleavage) and double electron processes for high differences (hetero liddick cleavage).

Explore single-electron alkane fragmentation and mass spectrometry, illustrating ethane and propane pathways, molecular ions, and fragment m/z peaks via fishhook arrows.

Identify common fragmentation patterns in mass spectrometry by recognizing methyl (-15) and ethyl (-29) losses from the molecular peak, illustrated by 72 to 57 and 72 to 43.

Explore how fragmentation pathways and fragment stability shape relative abundances in mass spectra. Compare primary, secondary, and tertiary carbocations with corresponding radicals in C5H12 isomers.

Analyze mass spectra to approximate molecular formulas using carbon 12, hydrogen 1, and oxygen 16; explore alkanes and oxygen-containing variants to identify plausible formulas.

Explore how carbon isotopes shape mass spectra to determine molecular formulas. Use C-12 and C-13 abundances, M and M+1 peaks, and correction factors to infer carbon count and alkane formulas.

Explore isotopic abundance through a space-people analogy, illustrating carbon-12 and carbon-13 proportions with a one-percent traitor rate and ships showing rising carbon-13 percent as carbons increase.

apply the nitrogen rule: an odd molecular ion implies an odd number of nitrogen atoms, often one, guiding how to adjust carbon and hydrogen to form a plausible formula.

Examine alkyl bromides and how bromine's 79/81 isotopes produce diagnostic M+2 peaks, with heterolytic C–Br cleavage giving 122/124 fragments.

Explore how chlorine isotopes 35 and 37 shape mass spectra of alkyl chlorides, comparing heterolytic and homolytic cleavage pathways, and identifying diagnostic M, M+2, and fragment peaks.

Explore how ethers fragment in mass spectrometry, detailing heterolytic and homolytic cleavage pathways, predicting key peaks such as m/z 88, 43, 29, and 73.

Explore alcohols in mass spectrometry, comparing their fragmentation to ethers, with detailed homolytic and heterolytic pathways and the characteristic water loss of 18 mass units.

Explore the fragmentation patterns of ketones in mass spectrometry, including the homiletic fragmentation pathway and the McClaughry rearrangement, with emphasis on alpha, beta, gamma designations.

Learn the fundamentals of nuclear magnetic resonance and compare it to infrared spectroscopy, showing how hydrogen and carbon-13 nuclei interact with an external magnetic field to produce spectra.

Explore the anatomy of an NMR spectrum, linking peak counts to unique proton environments, chemical shift (ppm), and integration and splitting to reveal hydrogen numbers and neighboring hydrogens.

This lecture shows how to predict the number of peaks in NMR spectra by identifying unique hydrogen environments, including CH2 equivalence, and using mirror plane equivalence with chloroform and TMS.

Identify how to predict hydrogen NMR peak counts by recognizing equivalent hydrogens through rotational equivalence and mirror plane equivalents, using Neumann projection to visualize rotations.

Predict the number of unique hydrogen NMR peaks by applying rotation and mirror symmetry to identify equivalent hydrogen sets across ketone, ether, and chlorinated molecules.

Predict how many peaks an alkene NMR spectrum will show by analyzing cis and trans alkenes, symmetry, and rotational equivalence to identify unique hydrogen sets.

Predict how benzene’s symmetry and resonance give a single peak, while substitutions like methyl or bromo disrupt equivalence and yield multiple, sometimes merged, peaks.

Explain how hydrogen chemical shifts map to functional groups across six regions, from carboxylic acids or aldehydes to saturated sp3 hydrogens, including benzene, vinyl, and allelic hydrogens.

Predict 1H NMR chemical shifts for bromo methane by identifying two hydrogen sets and linking peaks to germinal relationships with bromine, noting additive halogen effects.

Predict the number of peaks and chemical shifts for six molecules by combining peak-counting with shift estimation, covering carboxylic acids, ketones, chlorinated aromatics, benzene, and alkenes.

Learn how NMR integration reveals the relative number of hydrogens per peak, identify two distinct peaks A and B, and apply correction factors using the molecular formula to validate spectra.

compare two molecules by their nmr spectra, using peak counts, chemical shifts, and integration with correction factors to assign each spectrum. apply symmetry and a new moon projection to distinguish hydrogens.

Practice predicting chemical shifts, integration, and the total number of peaks for several molecules, from carboxylic acids to alpha to carbonyl and germinal protons.

this lecture introduces splitting patterns in NMR, defines neighboring hydrogens, explains the N+1 rule for singlets, and reviews common splits like singlet, doublet, triplet, quartet, and quintet.

Predict splitting patterns using the three bonds away rule, assign hydrogen sets A and B, and confirm with integration, spectrum shapes, and chemical shift evidence.

Engage in combo practice to apply all NMR spectroscopy skills—predict peak counts, shifts, integrations, and splitting for diverse molecules, including carboxylic acids and ethers.

Use degree of unsaturation to infer pi bonds and rings and assess linearity. Then apply a four-to-five step method with data tables and puzzle-piece hydrogen sets to predict structure.

Learn to determine the degree of unsaturation, assemble NMR data into a structured puzzle, and predict plausible structures featuring carbonyls and oxygen substitutions using ppm shifts and splitting patterns.

Learn how exchangeable protons in alcohols, amines, and carboxylic acids collapse NMR signals to singlets via rapid hydrogen exchange. Use deuterium shake tests and D2O to confirm exchangeability.

Master how J coupling shapes propyl group signals, predicting triplets, doublets, and sextets with Pascal's triangle, while noting long-range coupling and the N+1 rule.

Explains j3 coupling in alkenes, showing cis around 10 hz and larger trans values than alkanes, and illustrates germinal coupling and splitting patterns among hydrogen sets a, b, and c.

Explore funky splitting patterns on chiral sp3 carbons, where two-bond (2J) couplings can dominate and non-equivalent hydrogens produce doublet of doublets, explained via Newman projections and mirror planes.

Discover how carbon-13 NMR probes unique carbon atoms by counting peaks. Explore chemical shifts, why integration is limited for carbon, and how decoupling produces singlets for simpler spectra.

Predict carbon NMR peak counts by counting unique carbon environments, including quaternary carbons, and recognizing symmetry and rotational equivalence, plus note solvent effects like chloroform deuterated causing 77 ppm triplet.

Discover how carbon NMR chemical shifts map peaks to carbon types, from carbonyls in the 150–230 ppm region to sp3 carbons in 0–50 ppm, with regions treated as guides.

Apply qualitative integration rules in carbon-13 NMR to identify carbonyl and carbons with no hydrogens attached, and recognize decoupled singlet peaks due to solvent.

Combine 1H NMR and 13C NMR data with the molecular formula to deduce a structure from two spectra, using degree of unsaturation and carbonyl and nitrogen-containing ring considerations.

Apply degree of unsaturation, interpret IR carbonyl at 1720, and analyze two singlets in 1H NMR (9H tert-butyl, 3H methoxy) to identify a carbonate ester.

Combine infrared, 1H NMR, and mass spectrometry data to infer an aromatic alcohol with a benzene core, a methyl group, and an alkene, confirming with deuterium exchange.

Analyze how to combine 1H NMR, IR, and MS data to identify starting material and product in a substitution (SN2) reaction, including bromine and nitrogen signatures.

Learn to deduce a molecular structure using 1H NMR, 13C NMR, IR, and MS data when no molecular formula is given, using mass peaks and carbonyl cues.

Learn to fuse 1h nmr, 13c nmr, ir, and ms data from the final example to deduce a chlorine-containing carbonyl molecule, determine carbon count, and identify a chiral center.