Co(III) and Fe(III) complexes of Schiff bases derived from 2,4-dihydroxybenzaldehyde S-allyl-isothiosemicarbazonehydrobromide

Exploitation of a Half-Conjugate Polydentate Salamo-Salen Hybrid Ligand and Its Two Phenoxide-Bridged Heterohexanuclear 3d-s Double-Helical Cluster Complexes

A half-conjugate polydentate Salamo-Salen hybrid ligand, H₅L, containing two unique N₂O₂ pockets was first designed so that these metal ions in the complexes appear in different coordination modes. Two heterohexanuclear 3d-s double-helical cluster complexes, [Zn₄Ca₂L₂(μ₁-OAc)₂(EtOH)₂]·2EtOH (1; EtOH = ethanol) and [Zn₄Sr₂L₂(μ₂-OAc)₂(MeOH)₂]·2CH₂Cl₂ (2; MeOH = methanol), are reported that are formed through the reaction of H₅L with zinc(II) and calcium(II) acetate or strontium(II) acetate, respectively. IR spectral analysis of the two complexes showed the existence of monodentate- and bidentate-coordinated acetate ions. The fluorescence properties of the ligand and its two heterohexanuclear complexes were explored in MeOH and water solutions, separately. In addition, theoretical calculations (density functional theory, interaction region indicator, and bond order) were performed to further understand the formation of a single-molecular double helix and the electron distribution characteristics of the two complexes.

Synthesis, structural, cytotoxic and pharmacokinetic evaluation of some thiosemicarbazone derivatives

Iron(III) and nickel(II) complexes bearing a thiosemicarbazone framework were synthesized by a one-pot synthesis method. The structures were characterized by elemental analysis, IR, ¹ H NMR, APCI Mass, conductivity, magnetic moment measurements. Molecular and crystal structures of the iron(III) complex were obtained from single-crystal X-ray diffraction. The findings showed that the metal atom adopts a slightly distorted square-pyramidal coordination, with the four donor atoms of the thiosemicarbazone ligand defining the basal plane and a chloride atom occupying the apical position. In the crystal lattice, the structure is stabilized by intermolecular O─H···O and C─H···O interactions. The cytotoxic activity was studied by MTT assay, the expression levels of cytochrome P450 (CYP) enzymes by Western blot, and the lipophilicity (LogP) by using the shake-flask method, another pharmacokinetic parameter. The findings showed that the IC₅₀ values decreased with the decrease of the LogP values of the substances. Cytochrome P450 expression levels were found specific for each compound and each cell line. As a result, the pharmacokinetic properties of the newly synthesized thiosemicarbazone compounds are crucial for oral administration and provide us with clues for prospective in vivo studies.