Differences Between Naphthalene And Azulene

Naphthalene and azulene are both defined by the chemical formula C10H8. This makes naphthalene and azulene isomers, or a set of compounds with the same formula, but have different variation of arrangements in the molecule and therefore have different properties. In this case, naphthalene and azulene, naphthalene is composed of two six sided compounds, while azulene has a seven-sided ring and a five-sided ring. Azulene has large dipole movement due to buildup in charge in the five-sided ring at the expense of the seven-sided ring. The major difference between the HOMO and LUMO orbitals of naphthalene and azulene are the relative sizes of coefficients of the atomic orbitals that reflect the large difference in distribution of electron density for the two molecules in their respective state. For azulene, the transference of an electron from the HOMO to LUMO increases separation between electrons while reducing electron repulsion creating a lower electronic transition. However, this does not occur in the case of naphthalene. The transition of HOMO and LUMO leads to larger electron repulsion with a larger electronic transition energy in the case of naphthalene. …show more content…
The shorter wavelength results in a blue shift for the molecule. In addition, when a mono-substituted compound has decreased energy, when an EDG is placed on an odd carbon and a EWG is placed on and even carbon, the wavelength is longer than the wavelength of azuluene. The longer wavelength results in a red shift for the molecule. It can be concluded that mono-substituted compounds change absorption energies depending on whether the functional group is either an electron donating group or an electron withdrawing group, as well as the location of the functional group, either placed on an even or odd