Spectroscopy II

Introduction, generation—EI, CI, HEMS FD and FAB. Mass analyzer-electromagnetic field, quadrapole. Detection of molecular formula: molecular ion, molecular ion peak, Nitrogen rule, isotope peak, metastable ions; Fragmentation: basic fragmentation types and rules, factors influencing fragmentation, McLafferty rearrangement, fragmentation pattern of hydrocarbons, alcohols, ethers, ketones, aldehydes, carboxylic acids, amines, nitriles, nitro and halogenated compounds.

Self Study: Problems of mass spectral fragmentation of organic compounds for structure determination.

Electronic transitions (185-800nm), Beer- Lambert rule, bathochromic and hypsochromic shifts,effect of conjugation & auxochromes. Characterization of organic compounds: application of Woodward-Fieser rule to conjugated dienes, α,β-unsaturated carbonyl compounds, benzene and benzene  derivatives, polycyclic aromatic hydrocarbons, polyenes and polyenynes, steric effects in biphenyls and applications.

Fluorescence spectroscopy: An introduction to fluorescence spectroscopy.

Sampling, instrumentation and selection rules.

Quantitative studies: Force constants, relation between force constant and vibrational frequencies, factors effecting the shift in group frequencies: isotope effect, hydrogen bonding, solvent effect, electronic effects (inductive and mesomeric) and steric effect, different absorption regions in IR spectrum and vibrational coupling.

Characteristics functional group absorptions in organic compounds: carbon skeletal vibrations (alkanes, alkenes, alkynes, aromatic compounds), alcohols, phenols, ethers, ketones, aldehydes, carboxylic acids, amides, acid anhydrides, conjugated carbonyl compounds, esters, lactones, amines, amino acids (primary and secondary), interpretation of IR spectra of typical  organic compounds. An introduction to near IR. Overtones, combination bands and fermi-resonance.

Nuclear properties, Pulse techniques, Fourier Transform technique and its advantages, quantum number, chemical shift and factors affecting chemical shift, spin-spin interaction, factors affecting coupling constant, shielding mechanism, chemical shift values and correlation for protons bonded to carbon (aliphetic, olefinic, aldehydic annd aromatic) and other nuclei (alcohols, phenols, enols, carboxylic acids, amines, amides and meccaptans), proton exchange, deuterium exchange, complex spin-spin interaction between two, three, four and five nuclei (first order spectra).

Hindered rotation, Karplus curve variation of coupling constant with dihedral angle, simplification of complex spectra: nuclear magnetic double resonance, contact shift reagents, variable temperature dynamic NMR spectroscopy.

Solvent effects, nuclear Overhauser effect (NOE), a brief introduction of compounds carrying NMR active nuclei like N¹⁵, F¹⁹, P³¹.

¹³C NMR spectroscopy: Basic principles, chemical shift, (aliphatic, olefinic, alkyne, aromatic, heteroaromatic & carbonyl carbon), proton (¹H) coupled ¹³C NMR spectrum, off-resonance and noise decoupled ¹³C NMR spectrum, DEPT.

2DNMR spectroscopy– COSY, NOESY, HETCOR.

Structure elucidation of organic compounds by combined application of UV, IR, NMR and mass spectroscopy.