Explanation of cis and trans stilbene
Stilbene is a hydrocarbon consisting of a central ethylene group and two aromatic rings attached to either side. It has the molecular formula c14h12 and is a colorless, crystalline solid. Stilbene exists in two forms, cis and trans, which differ in the arrangement of the two aromatic rings with respect to the central ethylene group.
Structure of stilbene
Stilbene has a symmetrical structure with two phenyl rings attached to either side of a central ethylene group. The two phenyl rings can be oriented in two ways, either on the same side of the ethylene group (cis) or on opposite sides (trans).
Cis-stilbene
Cis-stilbene refers to the isomer of stilbene where the two phenyl groups are located on the same side (cis configuration) of the double bond. In this isomer, the substituents attached to the double bond are positioned on the same side of the molecule, resulting in a bent or zigzag shape.
Structure and properties
Cis-stilbene is a type of stilbene where the two phenyl rings are oriented on the same side of the ethylene group. This results in a bent, or “u” shape, in the molecule. Cis-stilbene has a melting point of 5-6°c and a boiling point of 305°c.
Applications
Cis-stilbene is commonly used in organic synthesis as a precursor for various chemicals and drugs, including tamoxifen, a drug used in the treatment of breast cancer.
Trans-stilbene
Trans-stilbene, on the other hand, refers to the isomer where the two phenyl groups are located on opposite sides (trans configuration) of the double bond. In this isomer, the substituents attached to the double bond are positioned on opposite sides of the molecule, resulting in a linear or straight shape.
Structure and properties
Trans-stilbene is a type of stilbene where the two phenyl rings are oriented on opposite sides of the ethylene group. This results in a linear, or “i” shape, in the molecule. Trans-stilbene has a melting point of 124°c and a boiling point of 309°c.
Applications
Trans-stilbene is used in the production of optical brighteners, which are additives used in laundry detergents to make clothes appear whiter and brighter.
Differences between cis and trans stilbene
The main difference between cis-stilbene and trans-stilbene lies in their molecular structure and spatial arrangement.
Here are some key differences:
1. Molecular structure:
A. Cis-stilbene: the two phenyl groups are located on the same side (cis configuration) of the central ethene double bond. This results in a bent or zigzag shape in the molecule.
B. Trans-stilbene: the two phenyl groups are located on opposite sides (trans configuration) of the central ethene double bond. This leads to a linear or straight shape in the molecule.
2. Physical properties:
A. Melting and boiling points: cis-stilbene generally has a lower melting and boiling point compared to trans-stilbene due to the differences in molecular shape and intermolecular interactions.
B. Solubility: trans-stilbene is typically more soluble in nonpolar solvents, while cis-stilbene tends to be less soluble due to its bent structure.
3. Optical properties:
A. Chirality: trans-stilbene is achiral, meaning it does not possess a chiral center and cannot rotate plane-polarized light. Cis-stilbene, however, can exhibit optical activity if it is present in a chiral environment.
B. Absorption and emission: the absorption and emission spectra of cis-stilbene and trans-stilbene may differ due to their distinct molecular conformations, leading to variations in their optical properties.
4. Reactivity:
A. Chemical reactions: the spatial arrangement of substituents in cis-stilbene and trans-stilbene influences their reactivity and ability to undergo specific chemical reactions. Some reactions may exhibit different rates or product formations depending on the isomer.
B. Stability: trans-stilbene is generally more thermally stable compared to cis-stilbene due to its linear structure, which allows for a more favorable overlap of molecular orbitals.
5. Biological activities:
A. Bioavailability: due to differences in solubility and molecular shape, the bioavailability and pharmacokinetics of cis-stilbene and trans-stilbene may vary.
B. Biological effects: stilbenes, including cis-stilbene and trans-stilbene, can exhibit different biological activities and potential health benefits. Specific isomers may have varying degrees of efficacy in various biological systems.
It is important to note that the differences between cis-stilbene and trans-stilbene extend beyond the points mentioned above, and further exploration and research are ongoing to understand their distinct properties and potential applications.
Importance and applications of stilbenes
Stilbenes, including cis-stilbene and trans-stilbene, are of significant importance and find various applications in different fields.
Here are some key areas where stilbenes are utilized:
1. Pharmaceuticals and medicine:
A. Antioxidant and anti-inflammatory properties: stilbenes, such as resveratrol (a derivative of trans-stilbene), exhibit potent antioxidant and anti-inflammatory effects. They have been studied for their potential benefits in cardiovascular health, cancer prevention, neuroprotection, and age-related diseases.
B. Anti-cancer properties: stilbenes have shown promising anti-cancer properties, including the ability to inhibit tumor growth and induce apoptosis (cell death) in cancer cells. Resveratrol, in particular, has been extensively studied for its potential in cancer prevention and treatment.
2. Cosmetics and skincare: stilbenes are used in cosmetic formulations and skin care products due to their antioxidant and anti-aging properties. They can help protect the skin against oxidative damage, reduce inflammation, and improve skin texture and elasticity.
3. Food and beverages: stilbenes, especially resveratrol, are naturally present in various foods and beverages, such as grapes, red wine, peanuts, and berries. They contribute to the health benefits associated with the consumption of these foods and are considered bioactive compounds with potential positive effects on human health.
4. Agriculture: stilbenes are known for their role in plant defense mechanisms. They are produced by plants in response to stressors such as uv radiation, pathogens, and pests. Stilbenes act as phytoalexins, protecting plants against various diseases and promoting their overall health. Additionally, stilbene-based compounds have been explored for their potential as natural pesticides and fungicides.
5. Polymer chemistry: stilbenes possess a unique property known as photoisomerization, which allows them to undergo reversible structural changes upon exposure to light. This property has been utilized in the development of photoresponsive materials and smart polymers with applications in optoelectronics, sensors, and nanotechnology.
6. Material science and optics: stilbenes have interesting optical properties, including fluorescence and phosphorescence, making them valuable in the development of dyes, pigments, and optical brighteners. They have also been employed in the synthesis of liquid crystals and as components in oled (organic light-emitting diode) devices.
The diverse applications of stilbenes highlight their importance in various industries, including pharmaceuticals, cosmetics, food, agriculture, and materials science. Ongoing research continues to explore their potential benefits and expand their range of applications.
Conclusion
The difference between cis and trans stilbene lies in their molecular structures, which affect their physical and optical properties. Trans-stilbene is more stable and optically active, while cis-stilbene has dipole-dipole interactions and is used as a starting material for various organic compounds. Both isomers have unique applications in various industries, making them important compounds in organic chemistry. So, now you know the difference between cis and trans stilbene! If you have any further questions, feel free to ask in the comments below.
