These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Intervalence near-IR spectra of delocalized dinitroaromatic radical anions.
    Author: Nelsen SF, Konradsson AE, Weaver MN, Telo JP.
    Journal: J Am Chem Soc; 2003 Oct 15; 125(41):12493-501. PubMed ID: 14531693.
    Abstract:
    The Class III (delocalized) intervalence radical anions of 1,4-dinitrobenzene, 2,6-dinitronaphthalene, 2,6-dinitroanthracene, 9,9-dimethyl-2,7-dinitrofluorene, 4,4'-dinitrobiphenyl, and 1,5-dinitronaphthalene show charge-transfer bands in their near-IR spectra. The dinitroaromatic radical anions have comparable but slightly larger electronic interactions (H(ab) values) through the same aromatic bridges as do the corresponding dianisylamino-substituted radical cations. H(ab) values range from 5410 cm(-)(1) (1,4- dinitrobenzene) to 3400 cm(-)(1) (9,9-dimethyl-2,7-dinitrofluorene), decreasing as the number of bonds between the nitro groups increases, except for the 1,5-dinitronaphthalene radical-anion, which has a coupling similar to that of 9,9-dimethyl-2,7-dinitrofluorene. All charge-transfer bands show vibrational fine structure. The vertical excitation energies (lambda(v)) were estimated from the vibrational components, obtained by simulation of the entire band. The large 2H(ab)/lambda(v) values confirm these radicals to be Class III delocalized mixed-valence species. Analysis using Cave and Newton's generalized Mulliken-Hush theory relating the transition dipole moment to the distance on the diabatic surfaces suggests that the electron-transfer distance on the diabatic surfaces, d(ab), is only 26-40% of the nitrogen-to-nitrogen distance, which implies that something may be wrong with our analysis.
    [Abstract] [Full Text] [Related] [New Search]