What is the Difference Between Cis and Trans Stilbene?

The main difference between cis and trans stilbene lies in the arrangement of the two phenyl groups attached to the central double bond. In cis-stilbene, the two phenyl groups are on the same side of the double bond, while in trans-stilbene, the phenyl groups are on opposite sides of the double bond. This difference in arrangement results in distinct physical properties for each isomer:

• Cis-stilbene:
• Liquid at room temperature (melting point: 5–6 °C).
• Sterically hindered and less stable due to steric interactions forcing the aromatic rings.
• Trans-stilbene:
• Crystalline solid at room temperature.
• Highly soluble in organic solvents.
• More stable due to the opposite arrangement of the phenyl groups.

Trans-stilbene is sometimes referred to as (E)-stilbene, while cis-stilbene is called (Z)-stilbene. The two isomers can be interconverted via photochemical reactions, and further reactions can produce phenanthrene.

Comparative Table: Cis vs Trans Stilbene

Cis and trans stilbene are isomeric forms of the compound stilbene, which consists of two benzene rings linked by a central ethylene bridge. They are aromatic alkenes that are geometrical isomers of each other, differing in the orientation of the two phenyl groups attached to the carbon atoms of the ethylene bridge. Here is a comparison table highlighting the differences between cis and trans stilbene:

The difference in physical properties, such as melting point and solubility, can be attributed to the different molecular structures and packing arrangements of cis and trans stilbene. Trans stilbene has a symmetrical structure, allowing it to be tightly packed and form a lattice, resulting in a higher melting point and lower solubility in water.