Cobalt(II) and nickel(II) chelates of some 5-pyrazolone-based, Schiff-base ligands

Abstract

The cobalt(II) and nickel(II) chelates of Schiff bases, derived by condensing 4-butyryl-3-methyl-1-phenyl-2-pyrazolin-5-one (BMPP) with o-, m-, p-phenylenediamine, benzidine, and ethylenediamine have been synthesized and characterized by elemental analyses, thermogravimetric analyses (TGA), conductance data, magnetic measurements, IR, 1 H NMR, 13 C NMR, mass, and electronic spectroscopies. Each of the Schiff bases was an ONNO donor to metal forming chelates formulated as [M(L)(H 2 O) 2 ] n with M ¼ Ni(II) and Co(II) and L is the di-anion of the Schiff base. The monomeric (n ¼ 1) and dimeric (n ¼ 2) species of these metal chelates, based on available evidence, are suggested.

N′-[(4Z)-1-(3-Methyl-5-oxo-1-phenyl-4,5-dihydro-1H-pyrazol-4-ylidene)hexyl]benzenesulfonohydrazide

“…For related studies of 4-acylpyrazol-5-one Schiff bases, see: Xu et al (2008); Peng et al (2005); Yang et al (2007). For their ligating ability towards metal ions and their biological activity, see: Parmar & Teraiya, (2009); Bedia et al (2006); Raman et al (2001); Uzoukwu et al (1996); Yang et al (2000); Chiba et al 1998). For their use as efficient extractants of metal ions in solution and recently as photochromic agents, see: Marchetti et al (2005); Marchetti et al (2000); Wu et al (2009).…”

“…Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al, 2006); software used to prepare material for publication: WinGX (Farrugia, 2012). Heterocyclic β-diketones with a pyrazol core and their derivatives have been the subject of investigation for decades because of their interesting ligating ability towards metal centres and biological activities (Parmar and Teraiya, 2009;Bedia et al, 2006;Raman et al, 2001;Uzoukwu et al 1996;Yang et al 2000;Chiba et al 1998). They are also known to act as efficient extractants of metal ions in solution and recently as photochromic agents (Marchetti, et al, 2005;Marchetti et al, 2000;Wu et al,2009).…”

Synthesis, Characterization and in vitro Antibacterial Activity of Co(II), Cu(II) and Ni(II) Complexes with 4-Acylpyrazol-5-one Schiff Bases

“…Heterocyclic β-diketones with pyrazol moiety and their derivatives possess remarkable capacity for coordination with transition metals giving rise to coordination compounds with varying structural geometry [1][2][3][4][5][6] . 4-Acylpyrazol-5-one Schiff bases are one of the most studied heterocyclic β-diketones.…”

“…The Ni(II) complexes were found to be paramagnetic species with magnetic moments values in the range 2.95-2.97 BM, which are consistent with octahedral geometry. The Ni(II) complexes display bands in the region 11,000-13,000, 15,000 cm -1 and 23,000-24,000 cm -1 that are assignable to 3 A2g → 3 T2g(F), 3 A2g → 3 T1g(F) and 3 A2g → 3 T1g(P) transitions, respectively 44 . The three bands in the region 10,000, 18,000 and 23,000 cm -1 observed for Co(II) complexes have been assigned to 4 T1g(F) → 4 T2g(F), 4 T1g(F) → 4 A2g and 4 T1g → 4 T1g(P) transitions, respectively 40 .…”

Syntheses, spectral characterization, thermal properties and DNA cleavage studies of a series of Co(II), Ni(II) and Cu(II) polypyridine complexes with some new schiff-bases derived from 2-chloroethylamine

“…The electronic spectra of Ni(II) complexes exhibited three well defined bands in the range of 250-450 nm. These bands were assigned to 3 transitions which corresponds to octahedral geometry [28,29]. The weak absorption bands in the spectra of complexes were contribution from spin allowed metal to ligand charge transfer, MLCT [20].…”