Photochemistry and Pericyclic Reactions by Jagdamba Singh & Jaya Singh — A Complete Guide
If you are an M.Sc Chemistry student or someone preparing for competitive exams like CSIR-NET, GATE, or BITSAT, you already know how tricky pericyclic reactions and photochemistry can get. Most textbooks either skim the surface or drown you in detail without enough solved examples to practice. Photochemistry and Pericyclic Reactions by Jagdamba Singh and Jaya Singh fills that gap rather well — it is written by teachers who have spent years in the classroom and understand exactly where students get stuck.
Now in its third edition, published by New Academic Science, this book has become a trusted companion across Indian universities. The ISBN is 978-1-906574-51-2, and it spans roughly 449 pages of carefully structured content that takes you from the fundamentals of molecular orbital theory all the way to applied photochemistry in nature and industry.
Who Wrote This Book — and Why
Jagdamba Singh, M.Sc., D.Phil., is a Professor in the Department of Chemistry at the University of Allahabad. His co-author Jaya Singh, M.Sc., D.Phil., is a Lecturer in the Department of Chemistry at L.R.P.G. College, Sahibabad (Ghaziabad). Their combined teaching experience shows on every page — the explanations feel like they come from someone who has watched hundreds of students struggle with the same concepts and has refined their approach accordingly.
The motivation behind the book is simple. During their years of teaching undergraduate and postgraduate classes, both authors noticed the absence of a concise yet thorough volume dedicated specifically to pericyclic reactions and photochemistry. Students kept asking for a single resource that covered the theory, the mechanisms, and enough practice problems to build real confidence. This book is their answer.
What Makes This Book Stand Out
Plenty of chemistry textbooks cover photochemistry as a chapter or two tucked inside a larger organic chemistry volume. This one gives the subject its full due. The treatment of pericyclic reactions, in particular, is among the most complete you will find at this level.
Chapters 2 through 5 walk through all four classes of pericyclic reactions — electrocyclic reactions, cycloaddition reactions, sigmatropic rearrangements, and group transfer reactions. Each is examined through multiple lenses: the Woodward–Hoffmann orbital correlation method, the Frontier Molecular Orbital (FMO) method, the Woodward–Hoffmann selection rules, and the Perturbation Molecular Orbital (PMO) method. Students often find the last two approaches especially helpful because they offer simple mnemonics for predicting the stereochemical course of these reactions without getting lost in heavy mathematics.
Beyond the core pericyclic content, the book dedicates individual chapters to the photochemistry of carbonyl compounds, photo rearrangements, photo reduction and oxidation, and the photochemistry of alkenes, dienes, and aromatic compounds. There is even a full chapter on photo substitution reactions at sp3 hybrid carbon, covering the Barton reaction and the Hofmann–Loeffler–Freytag reaction — topics that frequently appear in competitive exam papers.
Where this book really earns its place on your shelf is Chapter 14, which contains a large collection of problems along with their complete solutions. For exam preparation, having fully worked answers is invaluable. You can attempt a question, check your approach, and identify where your reasoning went off track.
A Closer Look at the Chapter Index
The book is organized into fourteen chapters, moving logically from molecular orbital foundations through the four pericyclic reaction classes, then into photochemistry proper, and finally into applied and natural-product photochemistry. Here is the complete chapter breakdown:
| Chapter | Title | Page Range |
|---|---|---|
| 1 | Pericyclic Reactions | 1–16 |
| 2 | Electrocyclic Reactions | 17–57 |
| 3 | Cycloaddition Reactions | 58–110 |
| 4 | Sigmatropic Rearrangement | 111–152 |
| 5 | Group Transfer Reactions | 153–159 |
| 6 | Introduction and Basic Principles of Photochemistry | 160–183 |
| 7 | Photochemistry of Carbonyl Compounds | 184–228 |
| 8 | Photo Rearrangements | 229–261 |
| 9 | Photo Reduction and Photo Oxidation | 262–268 |
| 10 | Photochemistry of Alkenes, Dienes and Aromatic Compounds | 269–300 |
| 11 | Photo Substitution Reactions at sp3 Hybrid Carbon Having at Least One Hydrogen | 301–311 |
| 12 | Photochemistry in Natural Products | 312–321 |
| 13 | Photochemistry in Nature and Applied Photochemistry | 322–345 |
| 14 | Problems and Their Solutions | 346–449 |
Chapter 1 builds the foundation by covering the construction of π molecular orbitals of ethylene and 1,3-butadiene, symmetry in π molecular orbitals, frontier molecular orbitals, and excited states. Without this groundwork, the selection rules in later chapters would feel arbitrary rather than logical.
Chapter 6 serves as the bridge into photochemistry, introducing energy of a molecule, electronic transitions, spin multiplicity, the Jablonski diagram, photolytic cleavage, and the fundamental laws of photochemistry including the Grotthuss–Draper law and Einstein's law of photochemical equivalence. Quantum yield is explained clearly, along with the reasons for high quantum yield in certain reactions.
The later chapters venture into genuinely interesting territory. Chapter 12 explores photochemistry in natural products — including dye-sensitised photooxygenations and the photochemistry of saturated ketones. Chapter 13 covers atmospheric photochemistry, the chemistry of vision, photography, photochromism, photoimaging, and polymer photochemistry. These applied topics often surprise students who assumed photochemistry was purely theoretical.
Who Should Read This Book
The short answer: M.Sc Chemistry students in both their first and second year. The book aligns closely with the syllabi of nearly all Indian universities, with only minor variations depending on the institution. If your course includes a paper on photochemistry or pericyclic reactions, this text will cover what you need.
Competitive exam aspirants benefit just as much. CSIR-NET, GATE, and BITSAT questions on pericyclic mechanisms, photochemical rearrangements, and stereochemical predictions are handled thoroughly here. The Woodward–Hoffmann rules, FMO method, and Hückel–Möbius approach are all presented with the kind of clarity that makes exam problem-solving feel systematic rather than guesswork.
Students preparing for IIT-JAM and other state-level entrance exams will also find the problem-solving chapter worth its weight in gold. Each chapter ends with its own set of problems and a glossary of key terms, which makes revision far more efficient.
Key Features at a Glance
- Four pericyclic reaction classes explained through multiple theoretical methods (FMO, correlation diagrams, Woodward–Hoffmann rules, PMO).
- Complete photochemistry coverage — from basic principles through carbonyl photochemistry, rearrangements, oxidation–reduction, and aromatic compound reactions.
- Applied photochemistry chapters covering vision, photography, photochromism, photoimaging, and polymer photochemistry.
- Dedicated problems and solutions chapter (Chapter 14) with extensive worked examples.
- Glossary and further reading at the end of every chapter for quick revision and deeper exploration.
- Aligned with Indian university M.Sc syllabi and major competitive exam requirements.
Final Thoughts
Finding a single textbook that handles both pericyclic reactions and photochemistry with equal depth is rare. Jagdamba Singh and Jaya Singh have managed to create something that works as a classroom textbook, a competitive exam resource, and a reference you can return to during research. The writing stays accessible without cutting corners on rigor, and the solved problems give you a practical way to test your understanding.
If pericyclic selection rules have ever confused you, or if you have struggled to keep Norrish Type I, Paternò–Büchi, and di-π-methane rearrangements straight in your head, this book will help bring order to that chaos. Download it from the link below and add it to your study arsenal.