Preface

**Section 3 Computational Photochemistry 103**

**Hydantoin 105** Ming-Der Su

**VI** Contents

**Catalysts 115**

Tibbetts

Lorena Iancu

Chapter 6 **Computational Study of the Photochemical Fragmentation of**

**Section 4 Applications of Photochemistry and Photophysics 113**

Chapter 7 **Photophysics and Photochemistry of Conformationally**

Chapter 8 **Au Nanoparticle Synthesis Via Femtosecond Laser-Induced Photochemical Reduction of [AuCl4]− 137**

Chapter 9 **Photochemical Degradation Processes of Painting Materials**

Muhammad Saeed, Muhammad Usman and Atta ul Haq

Chapter 10 **Fluorescence Dyes for Determination of Cyanide 179**

Issah Yahaya and Zeynel Seferoglu

Chapter 11 **Catalytic Degradation of Organic Dyes in Aqueous Medium 197**

Sankalan Mondal and Satyen Saha

**from Cultural Heritage 161**

**Restricted Triarylmethanes: Application as Photoredox**

Mallory G. John, Victoria Kathryn Meader and Katharine Moore

Rodica-Mariana Ion, Alexandrina Nuta, Ana-Alexandra Sorescu and

Photochemistry and photophysics (PP) are as old as our planet Earth. Even before the exis‐ tence of our planet, photochemistry was evident in the turbulent atmosphere of our planet. At present, photosynthesis is an excellent example of the natural photochemical and photo‐ physical process on which our life depends. In our eyes, PP processes occur that allow us to see. Needless to say, PP have always been present in our main branch of science. Fundamen‐ tally, the topic of PP arises due to the interaction of light and matter, but exists in several crossroads of mainstream disciplines such as chemistry, physics, biology, and material sci‐ ence. Further, in our daily life, we are surrounded by products that are obtained in some ways with the aid of PP. Numerous devices are constructed based on PP, the most popular example being the solar cells.

For any civilization to progress, steady access to energy is essential. The sun is unarguably the ultimate renewable and sustainable source of unlimited energy. Scientists are investigat‐ ing ways to exploit the potentials of radiations from the sun to convert into usable forms of energies like electrical energy. However, that is possible only using the knowledge learnt from PP. Modern society also depends heavily on "information technology." Scientists are interested in miniature devices related to information and communication down to the mo‐ lecular level for which again the knowledge and expertise on PP are a prerequisite.

Scientists working on light-matter interaction have increased considerably due to develop‐ ment in the state-of-the-art spectroscopic instrumentation. Light is often found to be the sil‐ ver bullet in chemical laboratories and often provides exciting products that are otherwise impossible to obtain thermally. However, complicacy in the photochemical reaction is enor‐ mous and yet to be fully understood. Therefore, it is necessary to have a more in-depth un‐ derstanding of the PP fundamentals that would enable us to contribute significantly in emerging fields like energy conversion, medicine, information, and nanotechnology. It is predicted that frontiers of PP will continue to contribute significantly in the development of new molecules and materials and related processes and thereby will play a crucial role in the development of science and technology.

There are various comprehensive and stand-alone textbooks on PP available in the market. The most famous one is: 'Modern Molecular Photochemistry of Organic Molecules' by N. J. Turro, followed by 'Fundamentals of Photochemistry' by K. K. Rohatgi-Mukherjee. These books, along with others, provide a crystal-clear idea on the common topics both in pictorial and intuitive terms. Due to the gravity of this subject area, one can find around 50 books/ chapters on 'photophysics' and close to 370 on 'photochemistry' (as revealed by SciFinder search). Topics of photophysics and photochemistry of polymer, laser materials, coordina‐ tion compounds, multichromophoric molecule, and nucleic acids are becoming more popu‐ lar lately. The research on PP is increasing as revealed by a SciFinder search with "photophysics and photochemistry" keywords. There were 554 references found with those keywords, while more than 10,000 references are traced having both photophysics and pho‐ tochemistry separately.

Finally, I wish to thank all who have contributed in making this project successful: I am thankful to all the contributors for their excellent chapters without which this book would not have been possible and to coeditor Dr. Sankalan Mondal for helping me in reviewing several chapters. The help and guidance from Author Service Manager, Ms. Dolores Kuzelj, is gratefully acknowledged. Sincere thanks are due to IntechOpen publishers, the world leader in open access publications for giving us the opportunity to publish this book with

**Satyen Saha and Sankalan Mondal**

Department of Chemistry Institute of Science

Banaras Hindu University

Varanasi, India

Preface IX

highest degree of professionalism.

This book entitled "*Photochemistry and Photophysics: Fundamentals to Applications*" presents various advanced topics that inherently utilize those core concepts/techniques of photochemistry and photophysics. The purpose of this book is to bring many of these topics together in one publication. The goal of this book is to familiarize both research scholars and postgraduate students with recent advances in various fields related to photophysics and photochemistry.

The book is broadly divided into four parts: Part I deals with photophysics, while Part II covers photochemistry. Part III deals in a lone chapter with computational aspects of photo‐ chemistry. Part IV contains the application aspects. Each part provides the unique aspect of photophysics and photochemistry.

This book starts with a vital chapter that is one of the most discussed topics in PP, "proton transfer." Yoonsoo Pang and coworkers have presented an excellent discussion on the vari‐ ous aspects of ultrafast intramolecular proton transfer reaction in anthraquinone derivatives. BODIPY dyes are vital and show exciting photophysics. López-Arbeloa and coworkers have described the tailoring of photophysical responses of BODIPY dyes in Chapter II.

Part II contains three chapters that are primarily on photochemistry. While Chapter III deals with the photoconversion mechanism of substituted amides of salicylic acid (written by Na‐ dezhda Medyanik and coworkers), Chapter IV deals with photochemical preservation tech‐ niques of natural water by photoinduced degradation of organics as described by Sarka Klementova. Chapter V by S. Baptista and coworkers deals with the photochemistry of lipo‐ fuscin in the skin.

A relatively uncommon chapter in this book is the computational aspect of photochemistry. The single chapter in Part III is written by Ming-Der Su on the computational study of pho‐ tochemical fragmentation of hydantoin.

There are five significant chapters in the last part of this book that fall under the heading of "applications of photochemistry & photophysics." Part IV starts with a chapter on 'photo‐ physics and photochemistry of conformationally restricted triarylmethanes' by Sankalan Mondal and Satyen Saha. A significant part of this chapter deals with applications of these molecules as photoredox catalysis. Laser-induced gold nanoparticle synthesis has been dis‐ cussed in Chapter VIII by K. M. Tibbetts and coworkers. For the preservation of cultural heritage such as monuments, paints are essential. Understanding photochemical degrada‐ tions of such things is significant and has been discussed by Lorena Iancu and coworkers in Chapter IX. Determination of ions, mainly which are crucial to human health, is significant. Chapter X deals with the determination of cyanides by fluorescence dyes as discussed by Zeynel Seferoglu and coworkers. The last chapter of this book is devoted to the catalytic degradation of organic dyes in aqueous medium, written by Muhammad Usman and cow‐ orkers.

Most of the chapters in this book aim to highlight the photophysics and the photochemistry of novel organic molecules used in different processes. Last but not the least, the future of photo‐ physics-photochemistry, like in any other burgeoning field, is more exciting than the past.

Finally, I wish to thank all who have contributed in making this project successful: I am thankful to all the contributors for their excellent chapters without which this book would not have been possible and to coeditor Dr. Sankalan Mondal for helping me in reviewing several chapters. The help and guidance from Author Service Manager, Ms. Dolores Kuzelj, is gratefully acknowledged. Sincere thanks are due to IntechOpen publishers, the world leader in open access publications for giving us the opportunity to publish this book with highest degree of professionalism.

lar lately. The research on PP is increasing as revealed by a SciFinder search with "photophysics and photochemistry" keywords. There were 554 references found with those keywords, while more than 10,000 references are traced having both photophysics and pho‐

This book entitled "*Photochemistry and Photophysics: Fundamentals to Applications*" presents various advanced topics that inherently utilize those core concepts/techniques of photochemistry and photophysics. The purpose of this book is to bring many of these topics together in one publication. The goal of this book is to familiarize both research scholars and postgraduate students with recent advances in various fields related to photophysics and

The book is broadly divided into four parts: Part I deals with photophysics, while Part II covers photochemistry. Part III deals in a lone chapter with computational aspects of photo‐ chemistry. Part IV contains the application aspects. Each part provides the unique aspect of

This book starts with a vital chapter that is one of the most discussed topics in PP, "proton transfer." Yoonsoo Pang and coworkers have presented an excellent discussion on the vari‐ ous aspects of ultrafast intramolecular proton transfer reaction in anthraquinone derivatives. BODIPY dyes are vital and show exciting photophysics. López-Arbeloa and coworkers have

Part II contains three chapters that are primarily on photochemistry. While Chapter III deals with the photoconversion mechanism of substituted amides of salicylic acid (written by Na‐ dezhda Medyanik and coworkers), Chapter IV deals with photochemical preservation tech‐ niques of natural water by photoinduced degradation of organics as described by Sarka Klementova. Chapter V by S. Baptista and coworkers deals with the photochemistry of lipo‐

A relatively uncommon chapter in this book is the computational aspect of photochemistry. The single chapter in Part III is written by Ming-Der Su on the computational study of pho‐

There are five significant chapters in the last part of this book that fall under the heading of "applications of photochemistry & photophysics." Part IV starts with a chapter on 'photo‐ physics and photochemistry of conformationally restricted triarylmethanes' by Sankalan Mondal and Satyen Saha. A significant part of this chapter deals with applications of these molecules as photoredox catalysis. Laser-induced gold nanoparticle synthesis has been dis‐ cussed in Chapter VIII by K. M. Tibbetts and coworkers. For the preservation of cultural heritage such as monuments, paints are essential. Understanding photochemical degrada‐ tions of such things is significant and has been discussed by Lorena Iancu and coworkers in Chapter IX. Determination of ions, mainly which are crucial to human health, is significant. Chapter X deals with the determination of cyanides by fluorescence dyes as discussed by Zeynel Seferoglu and coworkers. The last chapter of this book is devoted to the catalytic degradation of organic dyes in aqueous medium, written by Muhammad Usman and cow‐

Most of the chapters in this book aim to highlight the photophysics and the photochemistry of novel organic molecules used in different processes. Last but not the least, the future of photo‐ physics-photochemistry, like in any other burgeoning field, is more exciting than the past.

described the tailoring of photophysical responses of BODIPY dyes in Chapter II.

tochemistry separately.

VIII Preface

photochemistry.

fuscin in the skin.

orkers.

photophysics and photochemistry.

tochemical fragmentation of hydantoin.

#### **Satyen Saha and Sankalan Mondal**

Department of Chemistry Institute of Science Banaras Hindu University Varanasi, India

**Section 1**

**Primarily Photophysics**
