Related Experiment Video
Updated: Jun 20, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Correlation between the atomic alignment and the alignment of XeX* (B, C) rotation in the reactions of oriented Xe
1Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Abstract:
The polarization of the XeX* (B) and XeX* (C) emissions in the reactions of oriented Xe* ((3)P(2), M(J) = 2) + halogen (X)-containing molecules (CCl(4), CF(3)Br, CF(3)I, CH(3)I, NF(3)) has been measured as a function of each magnetic M(J)' substate in the collision frame. The parallel polarization of the XeX* (B, C) emissions to the relative velocity vector is commonly observed for all magnetic M(J)' substates. The correlation between the atomic alignment (M(J)') and the M(J)'-dependent alignment (A(M(J)')) of the XeX* (B, C) rotation is found to be extremely different between the XeX* (B) and XeX* (C) channels: For XeX* (B), A(M(J)') is highest for the M(J)' = 0 state, except CCl(4), whereas the |M(J)'| = 2 states give the highest A(M(J)') for XeX* (C). Alternatively, the correlation between the configuration (L(Z)') of the inner 5p orbital and the L(Z)'-dependent alignment (A(L(Z)')) of the XeX* (B, C) rotations is revealed. The collision with |L(Z)'| = 1 causes a similar positive alignment A(L(Z)') for the XeX* (B) and XeX* (C) channels. The alignment A(L(Z)') at the collision with |L(Z)'| = 0 is extremely different between the XeX* (B) and XeX* (C) channels. The collision with L(Z)' = 0 induces no alignment of XeX* (C) except CF(3)I, that is, A(L(Z)'=0) approximately 0, whereas it induces the higher positive A(L(Z)') of XeX* (B). The different M(J)' dependence on the alignment of the XeX* (B, C) rotation between the XeX* (B) and XeX* (C) channels can be recognized as the change of reaction mechanism due to the difference in the favorable impact parameter for each M(J)' state between the XeX* (B) and XeX* (C) channels, which reflects the Omega' conservation in the course of ion-pair (Xe(+)-RX(-)) formation.
More Related Videos
Related Concept Videos
Electrophilic Addition to Alkynes: Halogenation
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Alkyl Halides
Alkyl halides are halogen-substituted alkanes wherein one or more hydrogen atoms of an alkane is replaced by a halogen atom such as fluorine, chlorine, bromine, or iodine. The carbon atom in an alkyl halide is bonded to the halogen atom, which is sp3-hybridized and exhibits a tetrahedral shape.
Unlike alkyl halides, compounds in which a halogen atom is bonded to an sp2 -hybridized carbon atom of a carbon-carbon double bond (C=C) are called vinyl halides. Whereas aryl...
Hybridization of Atomic Orbitals I
Molecular Orbital Theory II
VSEPR Theory and the Effect of Lone Pairs

