Synthesis and spectral studies of the mesogenic Schiff-base, N, N′-di-(4′-pentyloxybenzoate) salicylidene-1,8-diamino-3,6-dioxaoctane and crystal structure of the Zn(II) complex

• Published in: Polyhedron 2008-01, Vol.27 (1), p.181-186
• Main Authors: Singh, Angad Kumar, Kumari, Sanyucta, Ravi Kumar, K., Sridhar, B., Rao, T.R.
• Format: Article
• Language: English
• Subjects: Crystal structure; Mesogenic Schiff-base; NMR spectra; Tetrahedral zinc(II) complex
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2007.09.002

A novel Schiff-base, N, N′-di-(4′-pentyloxybenzoate)salicylidene-1,8-diamino-3,6-dioxaoctane (H 2L 4) with the mesogenic phase, nematic droplets, was prepared and its structure studied by mass, NMR and IR spectra. The Schiff base reacts with Zn(II) as a di-negative tetra-dentate species, giving rise to a non-mesogenic tetrahedral complex, [ZnL 4]. The complex crystallizes in monoclinic P 2 1 / n which possesses screw axis and n-glide and also inherent twofold axis by the combination of these two symmetry operations. Considerable torsion has been observed between benzoate ring and salicylaldimine ring on either side of the metal atom. A novel Schiff-base, N, N′-di-(4′-pentyloxybenzoate)salicylidene-1,8-diamino-3,6-dioxaoctane (H 2L 4) with the mesogenic phase, nematic droplets, was prepared and its structure studied by elemental analyses and mass, NMR and IR spectra. The di-negative tetra-dentate bonding of the Schiff-base in the non-mesogenic complex, [ZnL 4], as implied on the basis of IR and NMR spectral data, was confirmed in the crystal structure of the monomeric tetrahedral Zn(II) complex. As per the crystal structure of the complex, the dinegative species of the ligand, L 4 2 - , coordinates to the Zn(II) ion through two phenolate oxygens and two azomethine nitrogens, rendering the overall geometry around Zn(II) to distorted tetrahedron.