The key difference between cis and trans stilbene is that in cis stilbene, the two phenyl groups are on the same side of the double bond whereas, in trans stilbene, the two phenyl groups are on the opposite sides of the double bond.
Cis and trans stilbene are aromatic alkenes that are geometrical isomers of each other. They differ from each other according to the orientation of the two phenyl groups that are attached to the two carbon atoms of the double bond.
CONTENTS
1. Overview and Key Difference
2. What is Cis Stilbene
3. What is Trans Stilbene
4. Side by Side Comparison – Cis vs Trans Stilbene in Tabular Form
5. Summary
What is Cis Stilbene?
Cis stilbene is an organic compound having two phenyl groups attached to the two carbon atoms of a double bond where the groups are oriented in the same direction. This compound falls under the category of diarylethenes. This name is given because this compound contains a cis ethane bond. The chemical formula of this organic compound is C14H12. Its molar mass is around 180 g/mol. At room temperature and pressure, this compound occurs in a liquid state.
Figure 01: Structure of Cis Stilbene
There are two isomers of stilbene: E isomer and Z isomer. Here, cis isomer of stilbene is named Z-stilbene. This compound is less stable due to the high steric hindrance since the two bulky phenyl groups are on the same side of the double bond. The melting point of cis stilbene is comparatively very low.
When considering the properties and applications of cis stilbene, it has the specific ability to undergo electrocyclic reactions. As a general property, it can undergo photoisomerization in the presence of UV radiation. This compound naturally occurs in plants. Moreover, this compound is useful in manufacturing dyes, as grain medium in dye lasers, etc.
What is Trans Stilbene?
Trans stilbene is an organic compound having two phenyl groups attached to the two carbon atoms of a double bond where the groups are oriented in opposite directions. It is the isomer of cis stilbene, and this compound is also named as E stilbene. It has the two bulky phenyl groups far from each other, making this compound more stable than cis isomers due to less steric hindrance. The chemical formula and molar mass of this compound are exactly similar to that of trans stilbene because they are structural isomers.
Figure 02: Structure of Trans Stilbene
At room temperature and pressure, trans stilbene exists in solid state. It is practically insoluble in water. This compound has a high melting point compared to its cis isomer. The most common method of producing this compound is the reduction of benzoin in the presence of zinc amalgam. There are several derivatives of trans stilbene that are used as dyes, optical brighteners, phosphors, and scintillators.
What is the Difference Between Cis and Trans Stilbene?
Cis and trans stilbene are organic compounds that are isomers of each other. The key difference between cis and trans stilbene is that in cis stilbene, the two phenyl groups are in the same side of the double bond whereas, in trans stilbene, the two phenyl groups are in the opposite sides of the double bond. Moreover, cis stilbene occurs in the liquid state while trans stilbene occurs in the solid-state.
Your can find more comparisons related to the difference between cis and trans stilbene in the below tabulation.
Summary – Cis vs Trans Stilbene
Cis and trans stilbene are organic compounds that are isomers of each other. The key difference between cis and trans stilbene is that in cis stilbene, the two phenyl groups are in the same side of the double bond whereas, in trans stilbene, the two phenyl groups are in the opposite sides of the double bond.
Reference:
1. Laane, Jaan. “Vibrational Potential Energy Surfaces in Electronic Excited States.” Frontiers of Molecular Spectroscopy, 2009, pp. 63–132., doi:10.1016/b978-0-444-53175-9.00004-0.
2. “(Z)-Stilbene.” Wikipedia, Wikimedia Foundation, 11 Oct. 2019, Available here.
Image Courtesy:
1. “Stilbene cis structure” By Su-no-G – Own work (Public Domain) via Commons Wikimedia
2. “Stilbene trans structure” (Public Domain) via Commons Wikimedia