Organic 8: Nucleophilic Substitution Flashcards
Nucleophile
an atom or ion that has an unshared electron pair which can be used to form a bond to carbon; = Lewis bases
Heterolytically
pertaining to the dissociation of a 2-electron covalent bond in which both electrons are retained by one of the initially bonded atoms; the 2 electrons in the carbon-halogen bond are lost with the leaving group
Substitution Nucleophilic Bimolecular (SN2)
mechanism proposed by Hughes and Ingold; concerted mechanism for nucleophilic substitution in which the nucleophile attacks carbon from the side opposite the bond to the leaving group and assists the departure of the leaving group
Inversion of configuration
reversal of the 3-d arrangement of the 4 bonds to sp^3 hybridized carbon
Steric hindrance
an effect on structure or reactivity that depends on van der Waals repulsive forces
Solvolysis
nucleophilic substitution in a medium in which the only nucleophiles present are the solvent and its conjugate base
Nucleophilicity
nucleophilic strength; a measure of how fast a Lewis base displaces a leaving group from a suitable substrate
Substitution Nucleophilic Unimolecular (SN1)
mechanism for nucleophilic substitution characterized by a 2-step process; the first step is rate-determining and is the ionization of an alkyl halide to a carbocation and a halide ion
Protic
solvents that have easily exchangeable protons, especially protons bonded to oxygen as in hydroxyl groups
Aprotic
solvents that do not have easily exchangeable protons such as those bonded to oxygen of hydroxyl groups
Dielectric constant
polarity of a solvent related to this measure of the ability of a material to moderate the force of attraction between oppositely charged particles
Polar solvents
solvents with high dielectric constants
Nonpolar solvents
solvents with low dielectric constants
