Matrix

• Organic chemistry is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds
• These compounds may contain many other elements, including hydrogen, nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur
• Organic compounds are ubiquitous
• They are central to the study of biology, medicine and petroleum
• Organic compounds form the basis of all known life on Earth
• Applications of organic chemistry include pharmaceuticals, plastics, food additives and explosives

Core Concepts

• Structure determines properties
• Structure elucidation, synthesis, and reactivity are the main foci of organic chemistry
• Carbon's tetravalency allows for a vast array of molecules
• Organic molecules can exist as isomers, having the same molecular formula but different structures and properties

Functional Groups

• Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules
• Common functional groups include:
  • Alcohols (-OH)
  • Ethers (R-O-R')
  • Aldehydes (RCHO)
  • Ketones (RCOR')
  • Carboxylic acids (RCOOH)
  • Amines (RNH2)
  • Amides (RCONH2)
• The properties and reactivity of an organic molecule are largely determined by the functional groups it contains

Alkanes, Alkenes, and Alkynes

• Alkanes are hydrocarbons containing only single bonds
  • They are saturated hydrocarbons
  • They have the general formula CnH2n+2
  • They are relatively unreactive
• Alkenes are hydrocarbons containing at least one carbon-carbon double bond
  • They are unsaturated hydrocarbons
  • They have the general formula CnH2n
  • They are more reactive than alkanes due to the presence of the pi bond
• Alkynes are hydrocarbons containing at least one carbon-carbon triple bond
  • They are unsaturated hydrocarbons
  • They have the general formula CnH2n-2
  • They are highly reactive due to the presence of two pi bonds

Isomerism

• Isomers are molecules that have the same molecular formula but different structural arrangements
• Structural isomers have different connectivity of atoms
• Stereoisomers have the same connectivity but different spatial arrangement of atoms
  • Enantiomers are stereoisomers that are non-superimposable mirror images
  • Diastereomers are stereoisomers that are not mirror images

Chirality

• Chirality refers to the property of a molecule that is non-superimposable on its mirror image
• A chiral center is typically a carbon atom bonded to four different groups
• Enantiomers have identical physical properties except for their interaction with plane-polarized light
• A racemic mixture contains equal amounts of both enantiomers and is optically inactive

Reactions

• Addition reactions involve the addition of atoms or groups of atoms to a molecule, typically across a multiple bond
• Elimination reactions involve the removal of atoms or groups of atoms from a molecule, typically forming a multiple bond
• Substitution reactions involve the replacement of one atom or group of atoms with another
• Rearrangement reactions involve the reorganization of atoms within a molecule

Reaction Mechanisms

• Reaction mechanisms describe the step-by-step sequence of elementary reactions that occur during a chemical transformation
• They involve the movement of electrons and the formation and breaking of chemical bonds
• Common mechanistic elements include:
  • Nucleophilic attack
  • Electrophilic attack
  • Leaving group departure
  • Proton transfer

Spectroscopy

• Spectroscopy is a technique used to determine the structure and properties of molecules by analyzing their interaction with electromagnetic radiation
• Common spectroscopic methods include:
  • Nuclear Magnetic Resonance (NMR) spectroscopy, which provides information about the carbon-hydrogen framework of a molecule
  • Infrared (IR) spectroscopy, which provides information about the functional groups present in a molecule
  • Mass spectrometry (MS), which provides information about the molecular weight and fragmentation pattern of a molecule
  • UV-Vis spectroscopy, which probes electronic transitions within the molecule.

Nomenclature

• IUPAC nomenclature is a systematic method for naming organic compounds
• It is based on identifying the parent chain, functional groups, and substituents
• The name provides information about the structure of the molecule

Acids and Bases

• Organic acids are compounds that can donate a proton (Brønsted-Lowry acid) or accept an electron pair (Lewis acid)
• Organic bases are compounds that can accept a proton (Brønsted-Lowry base) or donate an electron pair (Lewis base)
• The strength of an acid or base is determined by its pKa value
• Electron-withdrawing groups increase acidity, while electron-donating groups decrease acidity

Aromaticity

• Aromatic compounds are cyclic, planar, and have a continuous ring of p orbitals
• They follow Hückel's rule, which states that an aromatic compound must have 4n+2 pi electrons
• Aromatic compounds are exceptionally stable
• Benzene is the most common example of an aromatic compound

Stereochemistry

• Stereochemistry involves the study of the three-dimensional arrangement of atoms in molecules
• It includes the concepts of chirality, enantiomers, diastereomers, and meso compounds
• Stereoisomers have different physical and chemical properties
• Reactions can be stereoselective, favoring the formation of one stereoisomer over another, or stereospecific, where a specific stereoisomer of the reactant leads to a specific stereoisomer of the product

Main Reaction Types

• SN1: Unimolecular Nucleophilic Substitution
• SN2: Bimolecular Nucleophilic Substitution
• E1: Unimolecular Elimination
• E2: Bimolecular Elimination
• Addition Reactions
• Reduction Reactions
• Oxidation Reactions

Key Concepts

• Electronegativity: Describes how strongly an atom attracts electrons
• Inductive Effect: Transmission of charge through a chain of atoms in a molecule by electrostatic induction
• Resonance: Describes molecules with multiple valid Lewis structures
• Hybridization: Atomic orbitals mix to form new hybrid orbitals suitable for the pairing of electrons to form chemical bonds in valence bond theory. sp, sp2, and sp3
• Bond Length and Strength: Affected by bond order and atomic radii
• Thermodynamics: Enthalpy, entropy, and Gibbs free energy determine reaction spontaneity
• Kinetics: Reaction rates are influenced by activation energy and catalysts