bimolecular

(adjective)

Involving two molecules.

Related Terms

Examples of bimolecular in the following topics:

  • Elimination

    • In elimination, a uni- or bimolecular processes, a molecule loses an H and leaving group and a double bond is formed between vicinal carbon.
    • Like nucleophilic substitution, it can occur via unimolecular or bimolecular mechanisms.
    • In bimolecular elimination (E2), a base deprotonates a carbon vicinal to a leaving group, and the electrons from the C-H bond form a double bond with the adjacent carbon, displacing the leaving group.

  • Molecularity

    • A mechanism in which two reacting species combine in the transition state of the rate-determining step is called bimolecular.

  • Kinetics

    • In a simple bimolecular reaction n & m would both be 1, and the reaction would be termed second order, supporting a mechanism in which a molecule of reactant A and one of B are incorporated in the transition state of the rate-determining step.
    • A bimolecular reaction in which two molecules of reactant A (and no B) are present in the transition state would be expected to give a kinetic equation in which n=2 and m=0 (also second order).

  • Nucleophilic Substitution

    • This will be explained further in the detailed sections on unimolecular and bimolecular forms of nucleophilic substitution.
    • Bimolecular nucleophilic substitution (SN2) occurs in a one-step process that can be modeled as:

  • Grob Fragmentation

    • In the bottom epimer the chlorine atom is not oriented properly, and a slower bimolecular E2 elimination is observed.

  • Rate Laws for Elementary Steps

  • Substitution and Elimination Reactions of Amines

    • The energy diagram shown earlier for a single-step bimolecular E2 mechanism is repeated below.

  • The Alkyl Moiety

    • We call this description the SN2 mechanism, where S stands for Substitution, N stands for Nucleophilic and 2 stands for bimolecular (defined below).

  • The Collision Theory

  • Alkene Isomerization

    • Unlike the previously described unimolecular isomerizations, this compound is formed by a bimolecular reaction between an electronically excited stilbene and a ground state stilbene molecule.