Functional Group Chemistry

The ability of a molecule to attract electrons due to its electronegativity.

A functional group is a specific group of atoms within a molecule that gives the molecule its characteristic chemical properties.

A molecule that is attracted to electron-rich areas and accepts electrons.

A molecule or ion that donates electrons to an electrophile.

Stable atoms or groups that can leave a molecule during a reaction, creating a positive charge.

A molecule that is electron-deficient, often because it has a positive charge or a partially positive charge. This makes it susceptible to attack by nucleophiles.

Polarisation by proximity occurs when a molecule with a partial positive charge (δ+) is brought near an electron cloud. This enhances the positive charge making it more susceptible to attack.

Polarisation by proximity occurs when a molecule with a partial positive charge (δ+) is brought near an electron cloud. This enhances the positive charge making it more susceptible to attack by a nucleophile.

Good leaving groups are those that can easily detach from the substrate and form stable ions or neutral molecules. This often involves resonance stabilization.

A reactive intermediate with a positive charge, often formed during a reaction with a leaving group. It is highly reactive and will quickly seek out a nucleophile.

A single-headed arrow represents the movement of one electron, typically in radical reactions. It symbolizes the shift of an electron from one atom or bond to another.

A species containing an unpaired electron, often denoted by a dot next to its symbol.

A high-energy, short-lived molecular configuration that represents the transition between reactants and products in a chemical reaction.

A stable species that exists for a brief time during a chemical reaction, often formed as an intermediate step between reactants and products.

The energy difference between reactants and products in a chemical reaction. A positive value indicates an endothermic reaction, while a negative value indicates an exothermic reaction.

The energy required to reach the transition state in a chemical reaction. It determines the rate of the reaction.

The study of reaction mechanisms reveals the step-by-step process of a chemical transformation, providing insights into how molecules interact and transform.

A covalent bond between two atoms with unequal sharing of electrons, resulting in slightly positive and negative charges on the atoms. The more electronegative atom attracts the electron pair more strongly, creating a partial negative charge (δ-) and a partial positive charge (δ+) on the less electronegative atom.

Resonance forms are representations of the delocalization of electrons within a molecule, showing different possible arrangements of electrons without altering the position of the atoms. They help visualize how electrons are spread across a molecule.

Resonance structures are NOT isomers or different compounds. They represent the same molecule with different electron arrangements, contributing to the overall stability.

Resonance arrows are used to indicate the movement of electrons between resonance forms. They are double-headed arrows, showing the potential flow of electrons.

Resonance helps to explain the stability of certain molecules. It contributes to electron delocalization, which spreads out the electron density and stabilizes the molecule.

Only lone pairs and pi electrons can participate in resonance. The sigma electrons (those involved in single bonds) are localized and don't participate in resonance.

Resonance helps explain the behavior of molecules in reactions. It can explain how certain molecules are more reactive than others.

sp3 hybridized atoms, like carbon in methane (CH4), have all their electrons in sigma bonds. They cannot participate in resonance, because they have no p orbitals for electron delocalization.

Resonance structures are just representations of the electron distribution in real molecules. They don't exist as separate structures, but rather as an average of all the resonance forms.

A chemical reaction where an alcohol reacts with a carboxylic acid to form an ester and water. It is catalyzed by a strong acid, typically sulfuric acid, and is reversible.

A process where two molecules combine to form a larger molecule, releasing a smaller molecule, usually water.

The principle stating that changes in conditions, such as adding heat or removing product, will shift the equilibrium to relieve the stress.

The process of adding an electron to a molecule or atom, making it more negatively charged.

The process of removing an electron from a molecule or atom, making it more positively charged.

A chemical reaction where a hydroxyl group (OH) is replaced by a halogen atom, typically chlorine, bromine, or iodine.

An enzyme that catalyzes the oxidation of alcohols to aldehydes using NAD+ as a coenzyme.

An enzyme that catalyzes the oxidation of aldehydes to carboxylic acids using NAD+ as a coenzyme.

A drug that inhibits the activity of aldehyde dehydrogenase, leading to an accumulation of acetaldehyde, causing unpleasant side effects such as nausea and flushing.

The process of adding a hydrogen halide (HCl, HBr, or HI) to a molecule, usually an alcohol or alkene, resulting in the formation of a haloalkane. It is a nucleophilic substitution reaction.

A class of organic compounds characterized by the presence of a hydroxyl group (-OH) attached to a saturated or unsaturated carbon atom.

A measure of the tendency of a molecule to donate a proton (H+). Lower pKa values indicate stronger acids.

The tendency of a molecule's electron density to be pulled towards an atom or functional group. Electron-donating groups increase electron density, while electron-withdrawing groups decrease it.

An electron-donating group that increases electron density around a molecule.

An electron-withdrawing group that decreases electron density around a molecule.

A specific type of alcohol with a hydroxyl group directly attached to an aromatic ring.

A chemical reaction where an alcohol reacts with a strong acid to form an alkyl halide, with water as a byproduct.

A chemical reaction involving the addition of water to an alkene, resulting in the formation of an alcohol.

A chemical reaction in which a carbonyl compound is reduced to an alcohol.

The ability of a substance to dissolve in another substance, referring to the attractive forces between molecules.

Intermolecular forces that involve a dipole-dipole interaction between a hydrogen atom covalently linked to an electronegative atom (like oxygen) and an electron pair of another electronegative atom.

The ability of a molecule to attract electron density towards itself.

The tendency of a molecule to donate a pair of electrons to form a new bond with an electrophile.

The process of replacing one atom or group within a molecule with another.

The extent to which a molecule is capable of undergoing chemical reactions.

A chemical species that has a positive charge and is attracted to electron-rich areas.

The process of how a drug moves throughout the body, from absorption into the bloodstream to its excretion. It involves a series of steps: absorption, distribution, metabolism, and excretion.

A specific group of atoms within a molecule that determines its chemical properties and reactivity.

A molecule with the same functional group tends to have similar properties and reactions.

Drugs are often small organic molecules with a hydrocarbon part (usually non-reactive) and a functional group (where most of the reactions and interactions happen).

Understanding how functional groups affect molecular properties allows us to design new drugs and choose appropriate analytical methods.

A tetrahedral shape is adopted by sp3 hybridised carbon atoms. Its 3D structure can't be flattened. Wedged and hashed bonds are used to depict this structure. Bonds that point towards the viewer are shown as wedges, while those pointing away are shown as hashed bonds. Regular bonds are shown as if they are in the pane of the screen.

A chiral center is a carbon atom to which four different groups/atoms are attached. Chiral molecules have this center, which is essential for the development of stereoisomers.

A detailed step-by-step analysis of how a chemical reaction happens. This approach breaks down the reaction into a series of bond-making and bond-breaking steps.

A chemical process that involves the movement of two electrons in a specific sequence. This type of reaction involves polar bonds or charged species.

These species are electron-rich and readily donate electrons to an electrophile, usually with a pair of electrons represented by a curly arrow originating from the nucleophile.

A reaction involving the movement of one electron at a time, generating radical intermediates with an unpaired electron.

The stability of the intermediate radical formed during a reaction determines the distribution of products. More stable radicals are formed more readily, leading to a higher proportion of the corresponding product.

A tertiary radical (3o) is more stable than a secondary radical (2o), which is more stable than a primary radical (1o). The methyl radical is the least stable.

Alkyl groups, due to their electron-donating nature, stabilize radicals through hyperconjugation, a type of electron delocalization.

Hyperconjugation involves the interaction of electrons in a sigma bond with an adjacent empty p orbital or a pi orbital. This delocalization of electrons stabilizes the system.

The benzyl radical and the allyl radical are unusually stable due to resonance, which allows for delocalization of the unpaired electron.

Carbocations, like radicals, also follow a similar stability order: tertiary > secondary > primary > methyl. This trend is due to the same factors that stabilize radicals, such as hyperconjugation and inductive effects.

The more stable the intermediate radical, the more likely the reaction will occur to form that radical, resulting in a higher proportion of the corresponding product.

The reaction of free radicals involves the exchange of a hydrogen atom for a chlorine atom, often resulting in the formation of a new free radical.

Side reactions can occur during free-radical reactions, forming various byproducts alongside the desired product. These side reactions can be influenced by factors like temperature and the presence of inhibitors.

The distribution of substituted products in a reaction is influenced by the relative stability of the radicals that form as intermediates. The more stable the radical, the more likely it is to form, leading to a higher proportion of the corresponding product.

Alkenes are unsaturated hydrocarbons containing a carbon-carbon double bond (C=C). This double bond consists of one sigma and one pi bond, making the molecule more reactive than alkanes.

Alkenes are weakly polar due to the polarizability of the pi bond. This creates temporary dipoles, allowing for weak intermolecular interactions.

Alkenes exhibit cis-trans isomerism, where the arrangement of substituents around the double bond affects their spatial orientation. Cis isomers have substituents on the same side of the double bond, while trans isomers have substituents on opposite sides.

Hyperconjugation is a stabilizing interaction where electron density from neighboring C-H bonds overlaps with the empty p-orbital of the double bond. This increases the stability of more substituted alkenes.

Alkynes are unsaturated hydrocarbons containing a carbon-carbon triple bond (C≡C). This triple bond consists of one sigma and two pi bonds, making them even more reactive than alkenes.

Electrophilic addition is a fundamental reaction of alkenes and alkynes. It involves the attack of an electrophile, typically a proton (H+), to the electron-rich double bond.

Markovnikov's rule states that in the addition of a protic acid (HX) to an alkene, the hydrogen atom adds to the carbon with the most hydrogen atoms already attached.

Carbocation stability is important in predicting the regioselectivity of electrophilic addition. More stable carbocations are formed preferentially. Tertiary carbocations are the most stable, followed by secondary, and then primary.

Hydrohalogenation is a type of electrophilic addition where a hydrogen halide (HX, e.g., HCl, HBr) adds to an alkene, producing a haloalkane.

Hydration is a type of electrophilic addition where water (H2O) adds to an alkene, producing an alcohol. The reaction can occur under acidic conditions.

The addition of halogens like chlorine (Cl2), bromine (Br2), and sometimes iodine (I2) across the double bond of an alkene, resulting in the formation of a vicinal dihalide.

A type of addition reaction where the two new substituents add to the same side of the double bond, creating a cis or syn product.

A type of addition reaction where the two new substituents add to opposite sides of the double bond, creating a trans or anti product.

A three-membered ring intermediate formed during the addition of halogens to alkenes. It is formed by the attack of the alkene's pi electrons on the halogen molecule.

The process of converting an alkene to an alkane by adding hydrogen (H2) across the double bond. This reaction requires a metal catalyst like platinum (Pt), palladium (Pd), or nickel (Ni).

A rule that states that in the addition of a protic acid (HX) to an alkene, the hydrogen atom (H) will attach to the carbon atom that already has the most hydrogen atoms.

A type of organic compound characterized by the presence of a triple bond between two carbon atoms.

A chemical reaction where a molecule adds to a double or triple bond, breaking the pi bond and forming two new sigma bonds. This is a common reaction for alkenes and alkynes.

Alkynes are hydrocarbons containing a triple bond between two carbon atoms. This triple bond consists of one sigma bond and two pi bonds.

Terminal alkynes have the triple bond at the end of the carbon chain, while internal alkynes have the triple bond within the chain.

Alkynes have a general formula of CnH2n-2, indicating two fewer hydrogen atoms compared to alkanes with the same number of carbon atoms.

Terminal alkynes are more acidic than internal alkynes due to the electron-withdrawing effect of the sp hybridized carbon atom on the terminal hydrogen.

Alkynes undergo similar reactions to alkenes, including addition reactions with HX, X2, H2, and H2O. These reactions can be stopped at the monoaddition stage using one molar equivalent of reagent.

Alkynes undergo a nucleophilic substitution reaction called alkylation, where a terminal alkyne reacts with a primary alkyl halide to form a new carbon-carbon bond.

Alkynes are less reactive than alkenes due to the stronger triple bond.

The addition of HX to alkynes follows Markovnikov's rule, meaning the hydrogen atom adds to the carbon atom with more hydrogen atoms already attached.

Alkynes are virtually insoluble in water due to their nonpolar nature and weak intermolecular forces.

The triple bond in alkynes acts as a nucleophile, attracting electrophiles.