Structure, aggregation and spectroscopic properties of self-assembled Zn(II) Schiff base complexes

Nawal K. Al Rasbi, Harry Adams, Ibtisam Alshabibi, Fatma Alamri

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8 Citations (Scopus)

Abstract

The structures and photophysical properties of Zn(II) complexes with the tridentate Schiff base ligand HL: 1-((E)-((pyridin-2-yl)methylimino)methyl) naphthalen-2-ol, have been synthesized and fully characterized. The X-ray structures of the complexes showed unusual and inequivalent dimeric assemblies of Zn(II) that were tuned by the counter ions used. The complex [ZnL(HL)] 2(ClO4)2, 1, proves the self-assembly of a box-like structure that stabilized by OH⋯OR contacts within the complex. The complex [Zn2(μ-L)2(NO3)2], 2, contains two symmetrical Zn(II) centers that are directly linked by two oxo bridges from two ligands. The 1H NMR spectra in non-polar solvents such as CDCl3 confirmed the stability of the dimeric assemblies and aggregation in solution. By controlling the counter ions used, e.g. ClO 4 or NO3 and the polarity of solution, the Zn(II) complexes would form molecular aggregates at different extents with different emission properties in the solid and solution states. The solid-state emission spectra exhibited a spectral red-shift on the ligand-based emission besides a growth of a low-energy feature in 1 due to face-to-face π⋯π contacts between the aromatic rings in the box-like assembly. Therefore, complex 1 emits greenish-blue light and complex 2 emits blue light.

Original languageEnglish
Pages (from-to)37-43
Number of pages7
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume285
DOIs
Publication statusPublished - Jul 1 2014

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Keywords

  • Aggregation
  • Crystal structure
  • Emission
  • Zinc

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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