• Neuroscience & Pharmacology Discussion Welcome Guest
    Posting Rules Bluelight Rules
    Recent Journal Articles Chemistry Mega-Thread
    FREE Chemistry Databases! Self-Education Guide

  • N&PD Moderators: Skorpio

I'd like to learn more about Chemistry.

MedicinalUser247 said:
Do you know the difference between Polar v.s. Non-Polar @Skorpio ?
Click to expand...
First we need to get the concept of electronegativity. This is an atomic property where certain atoms attract electrons/electron density.

A polar compound is asymmetric, with one end having an atom (or a few atoms) significantly more electronegative than the other end. This causes the molecule to have a partial charge, with one end being more negative and one end being more positive.

Water is an example of a polar molecule, with its two hydrogens having a partial positive charge and the oxygen having a negative charge. Due to this polar molecules are often hydrophilic.

Non-polar molecules do not have a charge difference in the molecule. They are made of molecules with little or no difference in electronegativity. Propane is an example of a non-polar molecule.

Non-polar molecules tend to be hydrophobic.
 
Water, ethanol, acetone are fairly polar molecules. Likes dissolve likes. A polar solid like urea will dissolve in polar solvents.
Then in the middle you have your chloroform, methylene chloride. Diethyl ether is weakly polar.
THe non polars are hydrocarbons like @Skorpio said propane, hexane, octane, toluene, xylenes.

These are reasons why substances are immiscible or insoluble because of polarity differences.
My old advisor said dielectric constant is a measure of polarity maybe. iirc.
or the chromatographic series of eluents ranks solvents according to polarity.
 
Be careful with symmetry attributes. Because there's an entire expertise of chemistry using Group Theory and symmetry properties of molecules to calculate energy of molecular orbitals. Like water had a C2v point group which means it has a rotational axis 180degrees and 2 mirror planes of symmetry as well as an identity operation. You may also use spectroscopy to determine the energy gaps between orbitals based on electronic transitions to an excited state. Also is rotational (microwaves), vibrational (Infrared), and as mentioned electronic (UV/Vis) spectroscopy. reference to The Born-Oppenheimer approximation
 
Search Assist

Phenethylamines are generally considered polar compounds due to the presence of polar covalent bonds within their structure. However, the overall polarity can vary depending on the specific substituents attached to the phenethylamine backbone.
 
I'm not a chemist at all but very interested in this thread, hoping to learn more!
MedicinalUser247 said:
So even if they're Polar they can pass the BBB ?
Click to expand...
I think it's more complicated than that, a polar molecule can still pass the BBB but it might make it harder, however there are other things that might be a bigger factor on BBB e.g. the size of the molecule
 
en.wikipedia.org

Lipinski's rule of five - Wikipedia

en.wikipedia.org en.wikipedia.org

Lipinski’s rule of five is a pretty good heuristic for druglike action (plenty of drugs break that rule, but like many such “rules” it is a useful framework for drug design if you aren’t making weird stuff like protacs or macrolides or stuff that is actively transported).
 
Not in the RO5 but if you ever come across a compound with cis/trans isomerism, the trans isomers are likely to be the actives.
 
Vogel's Textbook of Practical Organic Chemistry

That was a required book for anyone studying chemistry past 16 in the UK.

An old second-hand copy is still probably just as good and unlike a digital document, it requires no power, cannot be hacked, corrosion resistant and isn't subject to someone editing it unbeknownst to the the end user. One of the few cases where having the physical book is of value.
 
couldn't find either of these books on libgen but they're on archive.org and clayden's is on google drive, just search for them with duckduck.

having had a quick flick through, I can tell I'm already outta my depth :ROFLMAO: :ROFLMAO::rolleyes:

doubtful I'll have the time to get through these in reality, heyho
 
As I said - a paper copy of Vogal's is better.

It isn't expensive if you don't mind an older edition and having seen them all, I conclude even a 30 year old copy is almost as good as the latest edition but far cheaper. £150 for a new one, £30 for the one I used.

It's printed on that special ultra-thin paper so if nothing else it makes servicable toilet paper in an emergency...
 
You must log in or register to reply here.
Top