Spectral Techniques in Organic Chemistry

General principles : Different regions  of electromagnetic radiation, quantisation of energy, regions of the spectrum. Introduction to absorption and emission spectroscopy.

UV Spectroscopy: Types of electronic transitions, λ_max, chromophores and auxochromes, bathochromic and hypsochromic shifts, intensity of absorption, application of Woodward Rules for calculation of λ_max for the following systems: α,β unsaturated aldehydes, ketones, carboxylic acids and esters; Conjugated dienes: alicyclic, homoannular and heteroannular; Extended conjugated systems (aldehydes, ketones and dienes); Distinction between cis and trans isomers.

Fundamental and non-fundamental molecular vibrations; IR absorption positions of O, N and S containing functional groups; Effect of H- bonding, conjugation, effect of resonance and ring size on IR absorptions; Fingerprint region and its significance; Overtones, Fermi resonance , Applications in functional group analysis.

Basic principles of Proton Magnetic Resonance, chemical shift and factors influencing it; Spin – Spin coupling and coupling constant; Anisotropic effects in alkene, alkyne, aldehydes and aromatics; Interpretation of NMR spectra of simple compounds like ethyl acetate, ethyl alcohol, acetaldehyde, 1,2 dibromo ethane, ethyl bromide etc.

¹³C NMR spectroscopy: general considerations, chemical shift, (aliphatic, olefinic, alkyne, aromatic, heteroaromatic & carbonyl carbon), proton (¹H) coupled ¹³C NMR spectrum, off resonance (elementary idea of ²D NMR spectroscopy: Cosy, Noesy NMR spectra), Structural determination of simple organic compounds using UV, IR & ¹H NMR spectral data.

Introduction, instrumentation, molecular ion-production, determination of molecular  weight – molecular ion peak, base 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, nitro compounds, alicyclic and heterocyclic compounds.