UV
I was just wondering how a solvent would affect the spectra of a compound.
Like a polar or nonpolar solvent for example:
polar: Methylene chloride
Nonpolar: cyclohexane, hexane, or ethanol
Thanks
This may be just a hint of what you are looking for.
http://answers.yahoo.com/question/index?qid=20080621111634AAE3LO0
And I consider ethanol as somewhat polar, at least more polar than the other two solvents you list.
Yes I saw that. I thoroughly looked this up before I came here...
That doesn't tell me what will I see.
What does "Agregate," mean?
I found out what I needed, I think.
Thank you for looking, Dr.Bob.
There are corrections to Woodward's rules for solvents which would help here. These below are for the uv max of a conjugated carbonyl and are in nm.
water + 8
chloroform - 1
ether - 7
cyclohexane - 11
dioxane - 5
hexane - 11
so the lower polarity solvent shifts the maximum to a lower wavelength and the more polar solvent to a higher wavelength.
The choice of solvent can indeed have a significant effect on the spectra of a compound, especially in the case of UV-visible (UV-Vis) spectroscopy. UV-Vis spectroscopy involves measuring the absorption or emission of light by a sample within the ultraviolet (UV) and visible range of the electromagnetic spectrum.
The primary factor that determines how a solvent affects the spectra of a compound is its polarity. A solvent can be either polar or nonpolar, depending on the distribution of electrical charges within its molecules.
In the case of polar solvents like methylene chloride, they have a high dielectric constant and contain polar functional groups. These solvents have a strong ability to stabilize charged or polar species. When a compound is dissolved in a polar solvent, it can undergo solvation, where the solvent molecules surround and interact with the compound's ions or polar groups. This solvation process can influence the electronic structure and stability of the compound, which in turn affects its UV-Vis spectra. The absorption intensity and wavelength may shift, broadening or narrowing the spectral lines, and sometimes even splitting the bands.
On the other hand, nonpolar solvents like cyclohexane, hexane, or ethanol have low dielectric constants and lack polar functional groups. They are less effective at solvating charged or polar species and provide a relatively inert environment. When a compound is dissolved in a nonpolar solvent, the solvent molecules do not interact strongly with the compound. In this case, the solvation effect is minimal, allowing the compound to exhibit its inherent electronic structure more directly. As a result, the UV-Vis spectra obtained in nonpolar solvents tend to be sharper, showing well-resolved absorption or emission bands.
It's worth noting that the polar/nonpolar nature of a solvent is not the only factor influencing the spectra. Other factors like temperature, concentration, and pH can also affect the spectra of a compound. Additionally, different compounds may exhibit varying degrees of sensitivity to solvent polarity.
To obtain specific information about how a solvent affects the spectra of a particular compound, it is recommended to consult scientific literature or references related to the compound of interest. Experimental data and studies conducted on that compound in different solvents can provide valuable insights into the solvent-solute interactions and resulting spectral changes.