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Title: Diradicals acting through diamagnetic phenylene vinylene bridges: Raman spectroscopy as a probe to characterize spin delocalization

We present a complete Raman spectroscopic study in two structurally well-defined diradical species of different lengths incorporating oligo p-phenylene vinylene bridges between two polychlorinated triphenylmethyl radical units, a disposition that allows sizeable conjugation between the two radicals through and with the bridge. The spectroscopic data are interpreted and supported by quantum chemical calculations. We focus the attention on the Raman frequency changes, interpretable in terms of: (i) bridge length (conjugation length); (ii) bridge conformational structure; and (iii) electronic coupling between the terminal radical units with the bridge and through the bridge, which could delineate through-bond spin polarization, or spin delocalization. These items are addressed by using the “oligomer approach” in conjunction with pressure and temperature dependent Raman spectroscopic data. In summary, we have attempted to translate the well-known strategy to study the electron (charge) structure of π−conjugated molecules by Raman spectroscopy to the case of electron (spin) interactions via the spin delocalization mechanism.
Authors:
; ; ; ;  [1] ; ; ; ;  [2] ;  [3] ; ;  [4] ; ; ;  [5]
  1. Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071 (Spain)
  2. Department of Molecular Nanoscience and Organic Materials, Institut de Ciència de Materials de Barcelona (CSIC), Campus Universitari de Bellaterra, E-08193 Cerdanyola, Barcelona (Spain)
  3. (CIBER-BBN), Campus Universitari de Bellaterra, E-08193 Cerdanyola, Barcelona (Spain)
  4. Dpt. de Química Física and IQTCUB, Fac. Química, Univ. de Barcelona, Av. Diagonal, 647, 08028-Barcelona (Spain)
  5. MALTA-Consolider Team, Department of Physical Chemistry, University Complutense of Madrid, Madrid 28040 (Spain)
Publication Date:
OSTI Identifier:
22253026
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 16; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COUPLING; ELECTRONS; INTERACTIONS; PROBES; RADICALS; RAMAN SPECTROSCOPY; SPIN; SPIN ORIENTATION; TEMPERATURE DEPENDENCE