CHARGE TRANSFER COMPLEXES by the book of solid state chemistry

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1. CHARGE TRANSFER COMPLEXES A BOON OF SOLID STATE REACTION PPT BY – SUMIT KHARKWAL CLASS – MSC (III SEM) CHEMISTRY

2. WHAT WE LEARN TODAY? INTRODUCTION - WHAT ARE CHARGE TRANSFER COMPLEXES? HOW THEY FORMED/ SYNTHESIS? TYPES OF CHARGE TRANSFER COMPLEXES USES OF CHARGE TRANSFER COMPLEXES IN PHYSICS, CHEMISTRY & BIOLOGY. ORGANIC CHARGE TRANSFER COMPLEXES (OCTC) USES OF ORGANIC CHARGE TRANSFER COMPLEXES.

3. INTRODUCTION Charge transfer complexes are molecular associations formed between two or more molecules, one of which is an electron donor (D) and the other an electron acceptor (A), resulting in the transfer of electrons and formation of a new molecular entity with distinct properties. Electron transfer refers to the process of transferring one or more electrons from a donor molecule (D) to an acceptor molecule (A), resulting in a change in oxidation states and formation of a charge transfer complex.

4. Donor-Acceptor Complexes In charge transfer complexes, the donor-acceptor interaction is the primary driving force for the formation of the complex. The donor-acceptor complex is a type of charge transfer complex where one molecule acts as an electron donor (D) and another molecule acts as an electron acceptor (A). Donor (D) A donor is a molecule that has a tendency to donate electrons. Donors typically have a high degree of electron density and are often molecules with lone pairs of electrons. Examples of donors include: Amines (e.g., NH3, N(CH3)3) Ethers (e.g., CH3OCH3) Alkenes (e.g., C2H4) Acceptor (A) An acceptor is a molecule that has a tendency to accept electrons. Acceptors typically have a low degree of electron density and are often molecules with empty orbitals. Examples of acceptors include: Nitro compounds (e.g., NO2, C6H5NO2) Quinones (e.g., C6H4O2) Metal ions (e.g., Ag+, Cu2+)

5. Types of Charge Transfer Complexes Importance: CTCs play a crucial role in various fields Crucial role : CTCs are essential for understanding and designing various phenomena and applications. Fields : The areas of research and application where CTCs are important, including: Chemistry : CTCs are relevant in organic chemistry, inorganic chemistry, and physical chemistry. Physics : CTCs are important in condensed matter physics, materials science, and spectroscopy. Biology : CTCs play a role in biochemistry, biophysics, and biomedical research.

6. Donor-Acceptor Interaction The donor-acceptor interaction is the attractive force between the donor and acceptor molecules. This interaction leads to the transfer of electrons from the donor to the acceptor, resulting in the formation of a charge transfer complex. The strength of the donor-acceptor interaction depends on the degree of electron density on the donor and the degree of electron deficiency on the acceptor. Types of Donor-Acceptor Complexes π-π* Complexes: Formed between two molecules with π (pi) orbitals, such as aromatic hydrocarbons. n-π* Complexes: Formed between a molecule with a lone pair of electrons (n orbital) and a molecule with an empty π* orbital. σ-π* Complexes: Formed between a molecule with a σ (sigma) orbital and a molecule with an empty π* orbital. Examples of Donor-Acceptor Complexes TTF-TCNQ: A classic example of a π-π* complex, formed between tetrathiafulvalene (TTF) and Emitting (TCNQ). Porphyrin-Quinone: An example of an n-π* complex, formed between a porphyrin molecule and a quinone molecule. Importance of Donor-Acceptor Complexes Donor-acceptor complexes play a crucial role in determining the properties of materials, such as conductivity, magnetic properties, and optical properties. Understanding donor-acceptor complexes is essential for designing materials with specific properties for various applications

7. USE OF CTC IN SOLID STATE CHEMISTRY Role of Charge Transfer Complexes in Solid State Reaction Can act as intermediates or catalysts in solid state reactions Can enhance the reactivity of solid state reactions Can influence the crystal structure and properties of the solid state product

8. USES Uses of Charge Transfer Complexes in Solid State Reaction Synthesis of organic semiconductors using charge transfer complexes as intermediates. Synthesis of metal-organic frameworks using charge transfer complexes as templates. Synthesis of OLED (Organic Light Emitting Diode) . Making of Different type of diode and transisters .

9. SYNTHESIS Synthesis of Charge Transfer Complexes by Solid State Reactions TTF-TCNQ : This complex can be synthesized by grinding TTF and TCNQ together and then heating the mixture at 150°C for 2 hours. Porphyrin-Quinone : This complex can be synthesized by milling porphyrin and quinone together and then heating the mixture at 200°C for 4 hours. Metal-Organic Frameworks (MOFs): MOFs can be synthesized by reacting metal ions with organic linkers using solid state reactions.

10. APPLICATIONS Applications of Charge Transfer Complexes Organic Electronics : Charge transfer complexes can be used as active layers in organic field-effect transistors (OFETs) and organic light-emitting diodes (OLEDs). Solar Cells : Charge transfer complexes can be used as active layers in organic solar cells. Sensors : Charge transfer complexes can be used as sensors for detecting specific molecules or ions. Catalysis : Charge transfer complexes can be used as catalysts for specific chemical reactions.

11. What is photodynamic therapy? Photodynamic therapy uses a drug that is activated by light, called a  photosensitizer  or  photosensitizing agent , to kill cancer cells. The light can come from a  laser  or other source, such as LEDs. Photodynamic therapy is also called PDT. Photodynamic therapy is most often used as a local treatment, which means it treats a specific part of the body. How photodynamic therapy treats cancer When cells that have absorbed photosensitizers are exposed to a specific wavelength of light, the photosensitizer produces a form of  oxygen , called an  oxygen radical , that kills them. Photodynamic therapy may also damage  blood vessels  in the tumor, which prevents it from receiving the blood it needs to keep growing. And, it may trigger the  immune system  to attack tumor cells, even in other areas of the body. A BOON : PHOTODYNAMIC THERAPY

12. How the light is applied depends on where the tumor is. For skin tumors, the light is aimed right at the cancer. For tumors in the throat, airways, and lungs, your doctor will insert an endoscope down your throat. An endoscope is a thin, lighted tube that can help the doctor see inside the body. Once the endoscope is in place, the doctor threads a fiber optic cable that transmits light through it to reach the treatment areas. One type of photodynamic therapy called  extracorporeal photopheresis  (ECP) is used to treat abnormal  white blood cells  that can cause skin symptoms in people with cutaneous T-cell lymphoma. In ECP, a machine collects your blood cells, treats them with a photosensitizer, exposes them to light, and then returns them to your body through a needle in a vein. Most often, you will have photodynamic therapy as an outpatient, which means you go home after treatment and do not spend the night in the hospital. You may have photodynamic therapy by itself, or you may have it along with other cancer treatments. How photodynamic therapy is given Photodynamic therapy is a two-step process . First, you will first receive a photosensitizer . The drug may be taken by mouth, spread on the skin, or given through an  IV , depending on where the tumor is in the body. After 24 to 72 hours, most of the drug will have left normal cells but remain in cancer or precancer cells. Then your tumor will be exposed to the light source. PROCEDURE

13. AREAS IN WHICH OCTC USED:-

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