i) I would need to know the relation between the dipole moment of the solute and the polarity of the solvent.
ii) How the dipole moment of the solute decrease in n → π* transition but increase in π → π* transition in case of polar solvent?
iii) What mean by the solvent can interact with the solute in its ground state or excited state?
i) Excited state dipole moment of the solute is expresed via Lippert-Mataga factor and Osager raidius. Many datails yuo can find in my minireview in ChePhysChem.
ii) Such an approach is incorrect, since the dipole moment, in a first approximation, does not depend on the properties of solvent.
iii) With increasing distance from the dissolved molecules interact with the solvent weaken, so the interaction with the environment and the electronic spectra depend on the number of solvent molecules located in the 1, 2 and 3 coordination spheres. Interactions with more distant solvent molecules often may be neglected.
You can read:
Solvents and Solvent Effects in Organic Chemistry, Christian Reichardt.
On the other hand I attached a paper with a light introduction to what you ask.
Luck
1) There are some theories concern that topic, Lippert-Mataga is one of them.
2) I am not sure of understand the question and i need more details. I thinck understand that your molecule is a non conjugated system and that you are able to see the transitions of separated form (n → π* and π → π*). If that is correct your affirmation is posible (The dipole moment of the solute decrease in n → π* transition). Remember that the coordination bond has ionic contribution, i.e. The N→B bond in the ground state has electronic redistribution from N to B which is "diminished" in the excited state, that is, dipole moment of the solute decrease IN THE EXCITED STATE for that moiety of the molecule (band in the electronic spectrum). You can find more about that in the paper atached.
Dear Hossam Attia
The article below may be helpful
http://dx.doi.org/10.1246/bcsj.44.3272
- Badges
- Science topic
- Similar topics
- Chemistry
- Theoretical Chemistry