Header menu link for other important links
X
A New Class of Nitroanilinic Dimer, the PNA O-Dimer: Electronic Structure and Emission Characteristics of O-Dimeric Aggregates
Nikhil Aggarwal,
Published in American Chemical Society
2015
Volume: 119
   
Issue: 30
Pages: 8388 - 8399
Abstract
p-Nitroaniline (PNA) has been reported as a J aggregate species. In retrospect, this communication confirms a radically different oblique orientation of the PNA units in all three solid, liquid, and gas phases of the dimer, the O-dimer. The nonvanishing transition dipole moments (TDM) associated with the allowed electronic excitations of the O-dimer, computed using electron-hole pair density distribution (EDD and HDD) analyses ascertained the two monomers to be inclined at slippage (π) and polarization (α) angles of 18.5° and 55.4°, respectively. A detailed structure-property relationship of the PNA O-dimeric aggregate was carried out using UV-vis absorption and matrix scan emission spectroscopy, supported by electronic structure calculations at DFT-M062X/6-31G+(d,p) level using integral equation formalism polarizable continuum model (IEFPCM). The computed potential energy surface (PES) implied the global minimum of the PNA O-dimer stabilized by 4.8 kcal.mol-1, owing to bifurcated intermolecular hydrogen bonding. In the excited PNA O-dimeric aggregate, an exchange of excitation energy between the monomeric units resulted in two distinct electronic states separated by an interaction energy of -1644 cm-1. The TD-DFT computed excited state equilibrium structures of the PNA O-dimer corroborated the experimentally observed pronounced Stokes shift to internal conversion following vibrational relaxation of the allowed electronic excited states. On the basis of the detailed structural analysis of PNA O-dimer, the observed energy shifts in optical absorption spectroscopy were evident within the framework of exciton coupling model. © 2015 American Chemical Society.
About the journal
JournalData powered by TypesetJournal of Physical Chemistry A
PublisherData powered by TypesetAmerican Chemical Society
ISSN10895639
Open AccessNo
Concepts (23)
  •  related image
    Absorption spectroscopy
  •  related image
    Aggregates
  •  related image
    Continuum mechanics
  •  related image
    Dyes
  •  related image
    Electric excitation
  •  related image
    Electromagnetic wave absorption
  •  related image
    Electronic structure
  •  related image
    Emission spectroscopy
  •  related image
    Excited states
  •  related image
    Hydrogen bonds
  •  related image
    Integral equations
  •  related image
    Light absorption
  •  related image
    Potential energy
  •  related image
    Quantum chemistry
  •  related image
    Electronic excited state
  •  related image
    Electronic structure calculations
  •  related image
    INTEGRAL EQUATION FORMALISMS
  •  related image
    Intermolecular hydrogen bonding
  •  related image
    Polarizable continuum model
  •  related image
    STATE EQUILIBRIUM STRUCTURES
  •  related image
    Structure property relationships
  •  related image
    TRANSITION DIPOLE MOMENTS
  •  related image
    Dimers