Mesogenic behaviour of (4‐alkoxybenzylideneamino)bromobenzene, (4‐alkoxybenzylideneamino)benzenethiols, and thiolatonickel complexes of the thiols

Abstract

The synthesis, characterization and mesogenic properties of Schiff base compounds arising from the reaction of 4‐alkoxybenzaldehydes with 4‐aminothiophenol or 4‐bromoaniline are described. Whereas the Schiff base thiol with two benzene rings in the molecule, HSC₆H₄NC(H)C₆H₄OC₁₆H₃₃ (2), is non‐mesogenic, the bromo analogue, BrC₆H₄NC(H)C₆H₄OC₁₆H₃₃ (3), is mesogenic. The introduction of a third benzene ring into the molecular architecture of 2 and 3 produced thiol‐ and bromo‐Schiff base compounds, HSC₆H₄NC(H)C₆H₄OC(O)C₆H₄OC₁₆H₃₃ and BrC₆H₄NC(H)C₆H₄OC(O)C₆H₄OC₁₆H₃₃, respectively, that are both mesogenic. The thiol compounds react with nickelocene to form [(η ⁵‐C₅H₅)Ni(μ ₂‐SC₆H₄NC(H)C₆H₄OC₁₆H₃₃)]₂ and [(η ⁵‐C₅H₅)Ni(μ ₂‐SC₆H₄NC(H)C₆H₄OC(O)‐C₆H₄OC₁₆H₃₃)]₂, but the nickel complexes are not mesogenic.

Acknowledgements

We thank Dr W. A. Ddamba, University of Botswana for some of the DSC data. We also thank the National Research Foundation (South Africa) for a postgraduate bursary (R.M.M.) and the University of the Western Cape (J.D.) for funding.