Synthesis, single crystal X-ray, spectroscopic characterization and biological activities of Mn2+, Co2+, Ni2+ and Fe3+ complexes

New cyanido-bridged iron(II) spin crossover coordination polymers with an unusual ladder-like topology: an alternative to Hofmann clathrates

Two new cyanido-bridged {FeIIMII} double chains were obtained by reacting cyanido anions [M(CN)4]2- with complex cations [FeII(tptz)]2+ (preformed in situ by mixing a hydrated tetrafluoroborate salt of iron(II) and a tptz ligand, tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazine) having the general formula [FeII(tptz)MII(CN)4]·2H2O·CH3CN, where M = Pd (1) or Pt (2). Additionally, two molecular complexes formulated as [FeII(tptz)2][MII(CN)4]·4.25H2O, where M = Pd (3) or Pt (4), were subsequently obtained from the same reaction, as secondary products. Single crystal X-ray analysis revealed that 1 and 2 are isostructural and crystallize in the P-1 triclinic space group. Their structure consists of a double-chain with a ladder-like topology, in which cyanido-based [M(CN)4]2- metalloligands coordinate, through three CN- ligands and three [FeII(tptz)]2+ complex cations. Compounds 3 and 4 are also isostructural and crystallize in the P1̄ triclinic space group, and the X-ray structural data show the formation of [FeII(tptz)2]2+ and [MII(CN)4]2- ionic units interconnected through H-bonds and π⋯π stacking supramolecular interactions. The static DC magnetic measurements recorded in the temperature range of 2-300 K showed that 1 and 2 exhibit incomplete spin transition on cooling, which is also confirmed by single crystal XRD analysis and Mössbauer spectroscopy. Compounds 3 and 4 are diamagnetic, most likely due to the encapsulation of Fe(II) in a tight pocket formed by two tptz ligands that preserve the low-spin state in the temperature range of 2-400 K.

Synthesis, structural investigations, and in vitro biological activity of Co(II) and Fe(III) mixed ligand complexes of 1,10-phenanthroline and 2,2'-bipyridine

Herein, we report, four new mixed ligand complexes of Cobalt(II) and Iron(III), viz., [Co(L₁ )(L₂ )(H₂ O)₂ ]Cl₂ (1), [Co(L₁ )(L₂ )(L₃ )(H₂ O)]Cl₂ (2), [Fe(L₁ )(L₂ )(H₂ O)₂ ]Cl₃ (3), and [Fe(L₁ )(L₂ )(L₃ )(H₂ O)]Cl₃ (4), where L₁  = 1,10-phenanthroline (C₁₂ H₈ N₂ ), L₂  = 2,2'-bipyridine (C₁₀ H₈ N₂ ), and L₃  = acetamide (C₂ H₅ NO)). They were synthesized and characterized using spectroscopic analysis (ESI-MS, ICP-OES, FT-IR, and UV-Vis), elemental analysis, melting point determination, and conductance measurement. The in vitro antibacterial activity was tested on two Gram-positive Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes) and two Gram-negative Escherichia coli (E. Coli)and Klebsiella pneumoniae (K. pneumoniae) bacteria using the disc diffusion method. Based on the analytical and spectroscopic data, octahedral geometries are assigned to the complexes. Co(II) complexes were found more active against K. pneumoniae than the corresponding Fe(III) complexes which indicated that antibacterial activities of metal complexes have tuned with the nature of the metal. The results provide an insight to design and readily prepare task-specific metal-based drugs for interaction with particular bacterial strains.

Coordination compounds of biogenic metals as cytotoxic agents in cancer therapy

The review summarizes the data on the structures and methods for the synthesis of compounds with anticancer activity based on biogenic metals, which can replace platinum drugs prevailing in cytotoxic therapy. The main focus is given to the comparison of the mechanisms of the cytotoxic action of these complexes, their efficacy and prospects of their use in clinical practice. This is the first systematic review of cytotoxic zinc, iron, cobalt and copper compounds. The structure – activity relationships and the mechanisms of antitumour action are formulated for each type of metal complexes.

The bibliography includes 181 references.

Synthesis and high antiproliferative activity of dehydroabietylamine pyridine derivatives in vitro and in vivo

Several bioactive dehydroabietylamine Schiff-bases (L1-L4), amides (L5-L11) and complex CuL3(NO3)2, Cu(L5)3, Co(L6)2Cl2 had been synthesized successfully for developing more efficient but lower toxic antiproliferative compounds. Their antiproliferative activities to Hela (cervix), HepG2 (liver), MCF-7 (breast), A549 (lung) and HUVEC (umbilical vein, normal cell) were investigated in vitro. The toxicity of all compounds was less than dehydroabietylamine (L0). For HepG2 cells, L1, L2 and L3 had higher anti-HepG2 activity, especially L1 (0.52 µM) had highest anti-HepG2 activity but low toxicity. For MCF-7 cells, L1, L2, L3 and L4 had higher anti-MCF-7 activity, especially L3(0.49 µM) had highest anti-MCF-7 activity but low toxicity. For A549 cells, L2 and L3 had higher anti-A549 activity. Furthermore, L1 and L3 may be the great promise antiproliferative drugs with nontoxic side effects, due to the high anti-HepG2 and anti-MCF-7 inhibition rate in vivo, 65% and 61%, respectively. L1, L2 and L3 could induce apoptosis through intercalating into DNA.

Charge-assisted hydrogen bond and nitrile⋯nitrile interaction directed supramolecular associations in Cu(ii) and Mn(ii) coordination complexes: anticancer, hematotoxicity and theoretical studies

Charge-assisted H-bonds and nitrile⋯nitrile interactions directed assemblies in Cu(ii) and Mn(ii) complexes have been analyzed by MEP surface and NCI plot index. Anticancer activities and hematotoxictiy have been investigated.