Nickel(II), palladium(II) and platinum(II) complexes of N-allyl-N′-pyrimidin-2-ylthiourea

Abstract

Platinum(II), palladium(II) and nickel(II) complexes with N-allyl-N¢-pyrimidin-2-ylthiourea were synthesized in 1:1 and 1:2 [metal:ligand] stoichiometric ratios and characterized by elemental analyses, molar conductivities, magnetic susceptibilities and by i.r., u.v.-vis., 1 H-and 13 C-n.m.r. and mass spectra. The 1 H-and 13 C-n.m.r. chemical shifts reveal coordination of one pyrimidine-N and sulphur atoms to Pt II and Pd II . The i.r. spectra indicate that the ligand behaves as a neutral monodentate towards Ni II ; coordinates via a pyrimidine-N and as a bidendate towards Pd II and Pt II coordinates via thione-S and a pyrimidine-N. The magnetic moments and electronic spectral data suggest a square-planar geometry for Pt II and Pd II complexes, a mixture of square-planar and tetrahedral geometries for the tetracoordinate Ni II complex and octahedral for the six-coordinate one. The E.I. mass spectra of the complexes showed some isotope ion peaks of [M] + and fragments containing metals; assignments of fragments containing metal ions were supported by the appearance of their peaks among isotope clusters.

Synthesis and spectroscopic characterization of Pt(II), Pd(II), Ni(II), Co(III) and Cu(II) complexes of N-allyl-N'-(4-methylthiazol)-2ylthiourea

“…Palladium(II) and platinum(II) complexes were prepared by the methods described previously [19,20]. Elemental analyses and some physical properties of the complexes formed are given in Table 1.…”

“…Platinum(II) and palladium(II) complexes show charge transfer bands at 305 -325 nm, the tails of which obscure the weaker dd transitions [37]. [19,20]. (ii) Small shifts occur for thiazole proton H(5') from 6.63 ppm in HL to 6.87-6.61 ppm.…”

“…This is an evidence for coordination of thiazole -N atom, not thiazole -S atom to metal ions, since the prominent withdrawing effect of the metal through σ-bonding on proton H(5') would be the prominent factor in case of the borderline acids Ni II and Co III , but through the distanceindependent extensive delocalized π-system as due to the pariciation of the soft acids Pd II ). This could be attributed to the two opposing effects of σ-electron withdrawing and π-bonding on the electron density around those carbons which are influenced by the metallic cations [19,20]. …”

Synthesis and characterization of 1-(4-methylthiazol-2-yl)-3-propyl thiourea

“…DOI: http://dx.doi.org/10.22192/ijarbs.2017.04.07.006 -1 H, 13 C -NMR spectra were measured on BRUKER 500 and 125 MHz, NMR apparatus with DMSO as solvent.…”

“…Thiazole and its derivatives are the main group of heterocyclic compounds, which have been found to possess useful bioactivity such as [12], antiinflammatory, anti-microbial [13], anti-tumor, and anti-fungal properties [14]. In recent years, thiazole derivatives have attracted large attention because of their bioactivity and some applications in organic and medicinal chemistry [15][16].…”