Structural and spectroscopic characterizations on the charge-transfer interactions of the second generation poly(propylene amine) dendrimers with iodine and picric acid acceptors

Spectrochim Acta A Mol Biomol Spectrosc. 2015 Feb 25:137:1270-9. doi: 10.1016/j.saa.2014.09.032. Epub 2014 Sep 22.

Abstract

Herein, this study was focused to get a knowledge about the intermolecular charge transfer complexes between the second generation of poly(propylene amine) dendrimer (PPD2) with picric acid (PA) and iodine (I2) as π and σ-acceptors. The charge-transfer interaction of the PPD2 electron donor and the PA acceptor has been studied in CHCl3. The resulted data refereed to the formation of the new CT-complex with the general formula [(PPD2)(PA)4]. The 1:4 stoichiometry of the reaction was discussed upon the on elemental analysis and photometric titration. On the other hand, the 1:3½ iodine-PPD2 heptaiodide (I7(-)) charge-transfer complex has been studied spectrophotometrically in chloroform at room temperature with general formula [(PPD2)](+)I7(-). The electronic absorption bands of 2I2·I3(-) (I7(-)) are observed at 358 and 294 nm. Raman laser spectrum of the brown solid heptaiodide complex has two clearly vibration bands at 155 and 110 cm(-1) due to symmetric stretching νs(II) outer and inner bonds, respectively. The (1)H NMR spectra and differential scanning calorimetry (DSC) data of PPD2 charge-transfer complexes were discussed.

Keywords: Dendrimer; Heptaiodide; Picric acid; Raman laser; Spectrophotometrically.

MeSH terms

  • Amination
  • Dendrimers / chemistry*
  • Electron Transport
  • Electrons
  • Iodine / chemistry*
  • Magnetic Resonance Spectroscopy
  • Picrates / chemistry*
  • Polypropylenes / chemistry*
  • Spectrophotometry
  • Spectrum Analysis, Raman

Substances

  • Dendrimers
  • Picrates
  • Polypropylenes
  • Iodine
  • picric acid