PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Inorganic chemistry → Main Group Chemistry ↓


Organosilicon chemistry


Organosilicon chemistry is a fascinating and diverse sub-discipline of chemistry that intersects with the fields of organic and inorganic chemistry. It deals with compounds that contain carbon-silicon (C-Si) bonds. Silicon, the second most abundant element in the Earth's crust, forms the backbone of this field that finds wide applications in materials science, drug development, agriculture and more.

Historical background

The study of organosilicon compounds began in earnest in the early 20th century. Early contributions laid the foundation for modern research and applications. The synthesis of silicon tetrahalides by Friedrich Wöhler in the 1840s was one of the earliest studies of silicon compounds. However, organosilicon chemistry did not really begin to develop its potential until the development of the silicon industry.

Basic concepts

Understanding organosilicon chemistry requires familiarity with the fundamentals of silicon chemistry:

  • The ability of silicon to form stable C-Si bonds.
  • Wide variety of possible silicon-containing clusters.
  • Organosilicon compounds exhibit unique properties such as thermal stability and hydrophobicity.

Chemical structure and bonding

Silicon's position in the periodic table is just below carbon. This gives it similar bonding characteristics but also some unique differences. Silicon can form compounds with many different elements, and its chemistry is primarily based on the formation of siloxane (Si-O-Si) and silane (Si-H) bonds.

SiH4 + 2 Cl2 → SiCl4 + 2 H2

In terms of bonding, organosilicon compounds often have silicon atoms bonded to alkyl or aryl groups. The Si-C bond is a sigma bond, which is typically quite strong, although weaker than a C-C bond, leading to different reactivity and stability results for compounds containing these bonds.

C Si

Synthesis of organosilicon compounds

Organosilicon compounds can be synthesized in several ways, the most common being the reaction of organomagnesium (Grignard reagents) or organolithium compounds with chlorosilanes:

R-MgX + R'SiCl → R-Si-R' + MgXCl

Some other synthetic routes include:

  • Hydrosilylation, where silanes are linked via carbon-carbon multiple bonds.
  • Direct process or Rochow process for the synthesis of methyl chlorosilane using a copper catalyst.

Applications of organosilicon compounds

Organosilicon compounds have wide applications in various industries. Here are some key areas where they make a significant impact:

Polymer industry

Perhaps the most prominent use of organosilicon compounds is in the production of silicones, a group of synthetic polymers composed of repeating units of siloxanes, which are widely used in everyday products.

R2SiO (N)

Silicones are used in sealants, adhesives, lubricants, medicine, cookware, and thermal insulation.

Pharmaceutical industry

Organosilicon chemistry also contributes to the pharmaceutical field. Organosilicon compounds are explored for their therapeutic potential due to their unique physicochemical properties such as increased lipophilicity, stability, and ability to enhance drug delivery mechanisms.

Agriculture

In agriculture, organosilicon compounds are used as surfactants and adjuvants, improving the delivery and effectiveness of insecticides and herbicides.

Properties and reactions

Organosilicon compounds have unique properties that make them suitable for a variety of industrial applications. These properties include:

  • Thermal stability: Silicon-containing polymers often exhibit high thermal stability due to the Si-O bond strength in the siloxane linkages.
  • Hydrophobicity: The Si-C bond provides water-repellent properties, making silicone suitable for waterproofing applications.
  • Flexibility: Silicones have flexibility at low temperatures, making them ideal in extreme weather conditions.

The chemistry of silicon is also interesting because of its ability to form hypercoordinate molecules. Unlike carbon, silicon can increase its coordination number beyond four. This leads to the formation of molecules such as pentacoordinate and hexacoordinate silicon compounds.

Important reactions involving organosilicon compounds

Understanding the unique reactivity of silicon leads us to several key reactions:

Hydrosilication

Hydrosilylation is an addition reaction in which a silane reagent adds to unsaturated carbon-carbon bonds (alkenes or alkynes). This reaction is important in the preparation of silicon-based materials:

R-Si-H + CH2=CH2 → R-Si-CH2-CH3

Kumada coupling

A variant of the cross-coupling reactions, the Kumada coupling, involves the coupling of organosilicon compounds with aryl or vinyl halides using nickel or palladium catalysts:

R-Si-R' + R"-X → RR" + X-SiR'

Environmental and health aspects

While organosilicon compounds offer significant industrial benefits, their impact on health and the environment remains a focus of ongoing research. Silicone polymers are generally considered non-toxic and harmless to the environment. However, the production and disposal of organosilicon compounds may pose environmental concerns due to the release of persistent and bioaccumulative materials.

Future perspectives

The future of organosilicon chemistry appears promising due to continuous innovations and the growing scope of its applications. Driven by advances in catalysis, materials science and sustainable chemistry, new avenues for research are constantly being explored, including:

  • Biocompatible silicones for medical applications.
  • Novel organosilicon polymers for environmentally friendly applications.
  • Next generation semiconductors and photovoltaic materials.

Overall, organosilicon chemistry is a dynamic and rapidly evolving field that continues to provide interesting challenges and opportunities for researchers around the world. As its applications grow, the need for a deeper understanding and control over their properties becomes even more important. Understanding and harnessing the unique properties and reactivity of organosilicon compounds will undoubtedly continue to be an important part of scientific exploration.


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Organosilicon chemistry

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