Spectroscopic Methods in Organic Chemistry (CHEM-476)

DESCRIPTION & OBJECTIVES

This course (Spectroscopic Methods in Organic Chemistry) focuses on the physical methods of characterization of isolated natural products (animal, fungal, marine and terrestrial sources), derivatives of natural products, bio/synthetic polymers and synthetic organic molecules of pharmacological importance. The new molecular entities isolated / synthesized are studied by these methods, which require only 5-10 mg quantity of the analyte as compare to chemical methods of analyses, to elucidate their molecular structure. This course does not cover the medical aspects of spectroscopy (commonly called Radiology) in broader spectrum. In fact, this course is a foundation course for Advance NMR (CHEM-741) and advance MS (CHEM-751) courses of MPhil with organic chemistry specialization.

The practical work involves the synthesis of a few small molecules in the laboratory by a reported protocol followed by workup, purification (involving crystallization, partitioning, chromatography) and comparative study of IR, UV, NMR and MS spectra of substrate and product(s).

READINGS

1. Williams, D. and Fleming, I. Spectroscopic Methods in Organic Chemistry, McGraw-Hill, New York (2009).

2. Anderson, R. J., Bendell, D. and Groundwater, P. Organic Spectroscopic Analysis – A Tutorial Chemistry Texts (serial-22), R. S. C. Publisher, Cambridge (2004).

3. Silverstein, R. M., Bassler, G. C. and Morrill, T. C. Spectrometric Identification of Organic Compounds, Wiley, New York (2005).

4. Kemp, W. Organic Spectroscopy, Macmillan, London (1990).

5. Younas, M. Organic Spectroscopy, A. H. Publisher, Lahore (2005).

6. Vogel, A. I. Practical Organic Chemistry, 5th Edition, Longman Publisher, London (1989).

CONTENTS

Theory:

A: IR Spectroscopy: Basic Principle, instrumentation and sample handling, interpretation of IR spectra, applications of IR spectroscopy.

B: UV/VIS Spectroscopy: Basic principle, instrumentation & sample handling, Woodward-Fieser rule for conjugated dienes and unsaturated carbonyl systems. Absorption by aromatic compounds. Applications of UV-Visible spectroscopy.

C: Mass Spectrometry: Basic Principle, instrumentation, modes of fragmentation of various organic molecules, Determination of molecular mass, molecular formula and molecular structure, interpretation of mass spectrum.

D: NMR Spectroscopy: Basic principle, spin flipping, spin relaxation, instrumentation and sample handling, the chemical shift (δ), spin-spin splitting and coupling constant (J), interpretation of NMR spectra.

E: Structure elucidation of organic compounds by joint applications of IR, UV, NMR spectroscopy and mass spectrometry.

Organic Chemistry Lab. III (Cr.01)

Experimental techniques e.g., distillation, solvent extraction, chromatography etc.
Multi-step synthesis of some organic compounds

3. Estimation of glucose and number of acetyl groups

COURSE SCHEDULE

Week	Topics and Readings	Dates
1.	Introduction to spectroscopy & spectrometry, EMR, Spectral bands, transitions	October 12-14, 2020
2.	Physical aspects of MW & IR spectroscopy	October 19-21, 2020
3.	Factors affecting IR absorbance	October 26-28, 2020
4.	Beer-Lambert’s Law, UV/Visible spectroscopy and its applications	November 2-4, 2020
5.	Chromophores, ε, λmax & factors affecting UV/Vis absorbance	November 9-11, 2020
6.	Introduction & instrumentation of mass spectrometry	November 16-18, 2020
7.	Fragmentation patterns of different FGs	November 23-25, 2020
8.	Different low / high resolution techniques (EIMS, APMS, CIMS, FAB, ESI, MALDI etc.) involved in mass spectrometry	November 30-December 2, 2020
9.	Nuclear / electronic spin (I), NMR vs ESR, NMR instrumentation	December 7-9, 2020
10.	Mid-Term Examination (December 14-18, 2020)
11.	Winter Break	December 21-24, 2020
12.	Chemical shift (δ), coupling constant (J) and factors affecting them	December 28-30, 2020
13.	Practice involving estimation / prediction of δ and J	January 4-6, 2021
14.	Spin-spin splitting; splitting patterns of 1Hs in different chemical environment; diastereotopy	January 11-13, 2021
15.	Introductory 13C-NMR (BB, DEPT-45°, DEPT-90° and DEPT-135°)	January 18-20, 2021
16.	Joint application of IR, UV/Vis, MS & 1H-NMR in solving small organic molecules	January 25-27, 2021
17.		February 1-3, 2021
18.	Final-Term Examination (February 8-12, 2021)

PRACTICAL / RESEARCH PROJECT

Multistep synthesis of different organic compounds followed by their purification by chromatographic (prep-tlc, cc) or other techniques (solvent extraction, crystallization etc.).
Characterization of the products by available spectroscopic (e.g. IR, UV etc.) / spectrometric (e.g., EIMS, ESI MS etc.) techniques.

ASSESSMENT CRITERIA

Mid Term Examination: 15% (Assigned assignment submitted in due time)

Sessional: 15% (Attendance = 5%, Assignments = 5%, class participation / conduct = 5%)

Project / Practical work: 25% (Attendance = 5%, Viva voce = 10%, quiz = 10%)

Presentation: included in sessional marks

Participation: 5% (already included in sessional marks)

Final examination: 45% (Subjective type=60%; Objective = 40%; premid : postmid course = 3:7,

2½ hours duration)

RULES AND REGULATIONS

Minimum attendance required for sitting in Mid and Final Examination = 75%