Spectroscopic characterization, crystallographic elucidation and DFT investigation of 5-fluoro-6-(4-methylpiperazin-1-yl)benzo[d]thiazol-2-amine

Thuraya S. Al-Harthy, Musa Shongwe, John Husband, Raphael Stoll, Klaus Merz, Raid Abdel-Jalil*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The spectroscopic features and molecular structure of 5-fluoro-6-(4-methylpiperazin-1-yl)benzo[d]thiazol-2-amine (2-ABT) have been determined. Single-crystal X-ray analysis and vibrational spectroscopy have revealed the existence of 2-ABT in the amino tautomeric form in the solid state. Properties of 2-ABT in solution have been investigated using 1H and 13C NMR spectroscopy along with electronic absorption spectroscopy. The experimental data are complemented by DFT and TD-DFT calculations at the B3LYP/6–311 + g(2d,p) level. TD-DTF-predicted spectroscopic and structural properties for both amino and imino tautomers of 2-ABT are compared with the measured data; no strong evidence for the presence of the imino tautomer is found within the experimental data. Calculated energy differences between the tautomers strongly favour the amino tautomer over the other. Indeed, X-ray crystallography has unequivocally shown the amino tautomer which co-crystallized with one water molecule in the orthorhombic space group Pnna. Analysis of the crystal packing reveals an interesting structural motif which comprises an assemblage of the 2-ABT molecules through π···π stacking interactions. Furthermore, there exist hydrogen-bonding interactions involving the lattice solvent and the amino group along with the benzothiazole nitrogen atom.

Original languageEnglish
Pages (from-to)614-621
Number of pages8
JournalJournal of Molecular Structure
Publication statusPublished - Jan 15 2019


  • 2-aminobenzothiazole
  • Amino-imino tautomer
  • DFT calculations
  • H-bonding interactions
  • Single-crystal X-ray

ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry
  • Inorganic Chemistry


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