Course

Unit 1

Tetrapyrrole Frameworks

Introduction to tetrapyrroles – role in biological processes (photosynthesis, oxygen transport). General structural features. Porphyrins, porphyrinoids and related macrocyclic tetrapyrroles. Fischer nomenclature and IUPAC nomenclature of porphyrins. Structure-nomenclature relationships.

Unit 2

Synthesis of Porphyrins

General strategies for porphyrin synthesis – Synthesis of β-substituted and meso-substituted porphyrins from monopyrroles, Rothemund method, Adler–Longo method, Lindsey method, Mechanistic considerations of porphyrin formation, Comparison of synthetic routes and reaction conditions.

Unit 3

Mechanism and Reactivity of Porphyrin Formation

Stepwise vs statistical porphyrin formation, Mechanistic aspects of acid-catalyzed condensation and oxidation, Factors governing macrocyclization efficiency, Side reactions and formation of porphyrin isomers, Influence of substituents on porphyrin stability and reactivity.

Unit 4

Metallation of Porphyrins

Concept and importance of metalloporphyrins, Metallation of porphyrins under different reaction conditions, Choice of metal ions and solvents, Kinetic vs thermodynamic control in metallation, Factors affecting metal insertion and stability.

Unit 5

Biomimetic and Functional Porphyrin Systems

Concept of biomimetic porphyrins, Porphyrins with appended peptides, Chelated hemes and axial ligand control, Porphyrins with covalently attached functional groups – Imidazole, pyridine, sulphur-donor groups, Quinone and other redox-active moieties, Picket fence porphyrins, Capped and strapped porphyrins, Structure–function relationships in biomimetic design

Text Books / References

Textbooks:

1. K. M. Kadish, K. M. Smith, R. Guilard, The Porphyrin Handbook, Vol. 1-10, Academic Press, San Diego, 1999; (b) K. M. Kadish, K. M. Smith, R. Guilard, The Porphyrin Handbook, Vol. 11-20, Academic Press, San Diego, 2003.
2. D. Dolphin, The Porphyrins, Volume 1: Structure and Synthesis, Part A, Academic Press, New York, 1978.
3. J. E. Merritt, and K. L. Loening, Pure & Appl. Chem., 1979, 51, 2251.

References:

1. T. Kitagawa and Y. Ozaki, Structure and Bonding, 1987, Vol. 64, 71
2. B. Morgan and D. Dolphin, Structure and Bonding, 1987, Vol. 64, 115

• CO1: Explain the structural features, biological significance and nomenclature of tetrapyrrole frameworks.
• CO2: Described and compare synthetic strategies for porphyrins.
• CO3: Describe the mechanism of porphyrin formation and effect of factors affecting stability and reactivity.
• CO4: Explain the principles of metallation of porphyrins, considering the selection of metal ions, reaction conditions and factors affecting stability and reactivity of metalloporphyrins.
• CO5: Describe the design of biomimetic and functional porphyrin systems and the relation between structure and functional properties.