Spectroscopic Methods of structure Elucidation: Course Outline (P-II)

Introduction

• Introduction to electromagnetic radiations
• Electromagnetic spectrum
• Interactions between electromagnetic radiations and molecules
• Index of hydrogen deficiency
• Energy-wavelength relations
• Molecular transitions and spectral regions

Ultraviolet and visible spectroscopy

• Radiation sources
• Monocheromators
• Detectors
• Single and double-beam
• Spectrophotometers
• Origin of molecular spectra
• Electronic transitions
• Solvent and steric effects
• Beer-Lambert law
• Calculation of λmax for different systems including dienes
• Enones and substituted benzoic acids
• Analysis of multicomponent systems and
• Applications of UV in structure elucidation

Infrared spectroscopy

• Near infrared spectroscopy
• Fourier transform infrared spectroscopy
• Instrumentation
• Vibrational modes and absorption frequencies
• Intensities  
• Sample
• Handling
• Characteristic absorption frequencies of different functional groups
• Applications of IR spectroscopy in qualitative and quantitative analysis

Nuclear magnetic resonance spectroscopy

Proton magnetic resonance spectroscopy (1H-NMR)

• Basic theory
• Concept of nuclear spin states
• Nuclear magnetic moment
• Chemical shift
• Molecular structure and chemical shifts
• Factors affecting chemical shifts
• Local diamagnetic shielding and magnetic anisotropy
• Spin- spin splitting  
• N+1 rule coupling constants
• Mechanism of coupling
• Factors effecting coupling constants
• Long range couplings
• Magnetic unequivalence
• Use of tree diagrams when n+1 rule fails
• Spin system notations
• Instrumentation (continuous wave (CW) instrument and pulsed fourier transform (FT) instrument
• A comparison of spectra at low and high field strengths
• Characteristic 1H-NMR absorption frequencies of different functional groups
• interpretation of 1H-NMR spectra

Carbon-13 magnetic resonance spectroscopy (13C-NMR)

• The carbon nucleus
• Carbon-13 chemical shifts
• Calculation of 13C chemical shifts
• Spin- spin splitting of carbon-13 signals proton coupled spectra and
• Proton decoupled spectra
• Nuclear overhauser enhancement (NOE) and origin of nuclear
• Overhauser effect
• Molecular relaxation processes
• Off resonance decoupling
• DEPT spectra
• 13C chemical shifts of different organic compounds and interpretation of 13CNMR spectra

Mass Spectrometery

• Basic principles
• Instrumentation (theory and operation)
• The mass spectrum
• Determination of molecular weight
• Determination of molecular formula
• Determination of molecular structure
• Interpretation of mass spectrum
• Fragmentation