Synthesis, Physicochemical, and Biological Properties of Nickel(II), Copper(II), and Zinc(II) Complexes of an Unsymmetrical Tetradentate Schiff Base and Their Adducts

<b>Studies on some VO(IV), Ni(II) and Cu(II) complexes of non-symmetrical tetradentate Schiff-bases</b>

“…and squareplanar complexes are diamagnetic [23]. The Ni(II) complexes reported in this work, are diamagnetic and consequently, four coordinate, square planar in geometry [19][20]23], ruling out the presence of paramagnetic, tetrahedral forms.…”

“…These ligands are widely studied because of their pronounced coordinating properties and stability [8][9]. A number of symmetrical Schiff bases and chelates have been reported [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], while comparatively little is known on synthesis and physico-chemical properties of asymmetric Schiff-base ligands and metal complexes [16][17][18][19][20]. Consequently, the aim of this work is to synthesize and characterize unsymmetrical Schiff-base ligands (derived from condensation of 1-phenyl-1,3-butanedione/2,4-pentanedione, ethylenediamine and 5-methoxy-2-hydroxy acetophenone) and their VO(IV), Ni(II) and Cu(II) complexes, in order to see the effect of the mixed π-electron ligand system and phenyl/methyl substituent on geometries and physico-chemical properties.…”

On the zinc(II) and mercury(II) compounds with Schiff-base N-(p-anisoyl)-2-oxo-1-naphthylideneamine. Tautomerism of the ligand and polymerization of mercury compound via Hg⋯I contact

“…Furthermore, at low wavenumbers, namely at about 450 cm -1 one weak-to-medium band in the spectra of the zinc complexes 1-3 is found; it can be ascribed to the stretching of the Zn−O bond [36,37]. In the IR spectra of the mercury complexes 4-6, an indication of the band at wavenumbers something lower than 450 cm -1 is present, but since the measuring range of the IR-spectrometer used in these experiments ends at 450 cm -1 it is not possible to detect the exact wavenumbers of these bands which could be ascribed to the Hg−O stretching.…”

The African black soap from Elaeis guineensis (Palm kernel oil) and Theobroma cacao (Cocoa) and its transition metal complexes

“…The strong band appearing at 1305 cm -1 attributable to υ (C-O) frequency has also disappeared in all its metal complexes. This also signifies the involvement of the oxygen of the ester group in chelation (Osowole et al, 2005;Adetoye et al, 2009;Ikotun et al, 2011;Oladipo et al, 2012).…”