Coordination of Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(II) with 2,5-hexanedione bis(thiosemicarbazone), HBTS: crystal structure of cis-[Pd(HBTS)]Cl2 and 1-(2,5-dimethyl-1H-pyrrol-yl)-thiourea

Synthesis, Characterization, and Anticancer Activity of Phosphanegold(i) Complexes of 3-Thiosemicarbano-butan-2-one Oxime

Four novel phosphanegold(I) complexes of the type [Au(PR3)(DMT)].PF6 (1-4) were synthesized from 3-Thiosemicarbano-butan-2-one oxime ligand (TBO) and precursors [Au(PR3)Cl], (where R = methyl (1), ethyl (2), tert-butyl (3), and phenyl (4)). The resulting complexes were characterized by elemental analyses and melting point as well as various spectroscopic techniques, including FTIR and (1H, 13C, and 31P) NMR spectroscopy. The spectroscopic data confirmed the coordination of TBO ligands to phosphanegold(I) moiety. The solution chemistry of complexes 1-4 indicated their stability in both dimethyl sulfoxide (DMSO) and a mixture of EtOH:H2O (1:1). In vitro cytotoxicity of the complexes was evaluated relative to cisplatin using an MTT assay against three different cancer cell lines: HCT116 (human colon cancer), MDA-MB-231 (human breast cancer), and B16 (murine skin cancer). Complexes 2, 3, and 4 exhibited significant cytotoxic effects against all tested cancer cell lines and showed significantly higher activity than cisplatin. To elucidate the mechanism underlying the cytotoxic effects of the phosphanegold(I) TBO complexes, various assays were employed, including mitochondrial membrane potential, ROS production, and gene expression analyses. The data obtained suggest that complex 2 exerts potent anticancer activity against breast cancer cells (MDA-MB-231) through the induction of oxidative stress, mitochondrial dysfunction, and apoptosis. Gene expression analyses showed an increase in the activity of the proapoptotic gene caspase-3 and a reduction in the activity of the antiapoptotic gene BCL-xL, which supported the findings that apoptosis had occurred.

Spectral, thermal, molecular modeling and biological studies on mono- and binuclear complexes derived from oxalo bis(2,3-butanedionehydrazone)

Background

Hydrazones and their metal complexes were heavily studied due to their pharmacological applications such as antimicrobial, anticonvulsant analgesic, anti-inflammatory and anti-cancer agents. This work aims to synthesize and characterize novel complexes of VO²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Zr⁴⁺and Pd²⁺ ions with oxalo bis(2,3-butanedione-hydrazone). Single crystals of the ligand have been grown and analyzed.

Results

Oxalo bis(2,3-butanedionehydrazone) [OBH] has a monoclinic crystal with P 1 21/n 1 space group. The VO²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Zr⁴⁺ and Pd²⁺ complexes have the formulas: [VO(OBH–H)₂]·H₂O, [Co(OBH)₂Cl]Cl·½EtOH, [Ni₂(OBH)Cl₄]·H₂O·EtOH, [Cu(OBH)₂Cl₂]·2H₂O, [Zn(OBH–H)₂], [Zr(OBH)Cl₄]·2H₂O, and [Pd₂(OBH)(H₂O)₂Cl₄]·2H₂O. All complexes are nonelectrolytes except [Co(OBH)₂Cl]Cl·½EtOH. OBH ligates as: neutral tetradentate (NNOO) in the Ni²⁺ and Pd²⁺ complexes; neutral bidentate (OO) in [Co(OBH)₂Cl]Cl·½EtOH, [Zr(OBH)Cl₄]·2H₂O and [Cu(OBH)₂Cl₂]·2H₂O and monobasic bidentate (OO) in the Zn²⁺ and VO²⁺ complexes. The NMR (¹H and ¹³C) spectra support these data. The results proved a tetrahedral for the Zn²⁺ complex; square-planar for Pd²⁺; mixed stereochemistry for Ni²⁺; square-pyramid for Co²⁺ and VO²⁺ and octahedral for Cu²⁺ and Zr⁴⁺ complexes. The TGA revealed the outer and inner solvents as well as the residual part. The molecular modeling of [Ni₂(OBH)Cl₄]·H₂O·EtOH and [Co(OBH)₂Cl]Cl·½EtOH are drawn and their molecular parameters proved that the presence of two metals stabilized the complex more than the mono metal. The complexes have variable activities against some bacteria and fungi. [Zr(OBH)Cl₄]·2H₂O has the highest activity. [Co(OBH)₂Cl]Cl·½EtOH has more activity against Fusarium.

Conclusion

Oxalo bis(2,3-butanedionehydrazone) structure was proved by X-ray crystallography. It coordinates with some transition metal ions as neutral bidentate; mononegative bidentate and neutral tetradentate. The complexes have tetrahedral, square-planar and/or octahedral structures. The VO²⁺ and Co²⁺ complexes have square-pyramid structure. [Cu(OBH)₂Cl₂]·2H₂O and [Ni₂(OBH)Cl₄]·H₂O·EtOH decomposed to their oxides while [VO(OBH–H)₂]·H₂O to vanadium. The energies obtained from molecular modeling calculation for [Ni₂(OBH)Cl₄]·H₂O·EtOH are less than those for [Co(OBH)₂Cl]Cl·½EtOH indicating the two metals stabilized the complex more than mono metal. The Co(II) complex is polar molecule while the Ni(II) is non-polar.

Graphical abstract

Electronic supplementary material

The online version of this article (doi:10.1186/s13065-015-0135-y) contains supplementary material, which is available to authorized users.

Crystal structure, complexation, spectroscopic characterization and antimicrobial evaluation of 3,4-dihydroxybenzylidene isonicotinyl-hydrazone

A single crystal of 3,4-dihydroxybenzylidene isonicotinylhydrazone, HBINH, has been grown and solved by X-ray crystallography. The VO(2+), Zr(4+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Pd(2+) complexes of HBINH have been prepared and spectroscopically characterized. The data confirmed the formulae [Co(HBINH)(H2O)Cl]Cl·H2O, [Pd(HBINH)Cl2], [Zn(HBINH)2Cl2], [Cd(HBINH)(H2O)2Cl2]·1½H2O, [(VO)2(HBINH-3H)(OH)(H2O)], [Ni2(HBINH)(H2O)6Cl2]Cl2, [Cu2(HBINH-3H)(H2O)2(OAc)]·3H2O, [Zr2(HBINH-3H)Cl4]Cl, [Hg2(HBINH)Cl4] and the dimer {[Cu(HBINH)Cl]Cl}2. Most of the complexes have intense colors and high melting points and some are electrolytes in DMSO solution. The ligand behaves as a neutral bidentate in the Co(II), Cu(II), Pd(II), Zn(II) and Cd(II) complexes; dibasic tetradentate in [Ni2(HBINH)(H2O)6Cl2]Cl2 and tribasic tetradentate in [Cu2(HBINH-3H)(OAc)]·5H2O, [(VO)2(HBINH-3H)(OH)(H2O)] and [Zr2(HBINH-3H)Cl4]Cl by the loss of 3H(+) due to the deprotonation of the two hydroxyl groups and the enolization of the amide (OCNH) group. A tetrahedral geometry was proposed for the Co(II), Cu(II), Zn(II) and Hg(II) complexes; square-planar for the Pd(II) complex; square-pyramid for the VO(2+) complex and octahedral for the Ni(II) and Cd(II) complexes. The complexes [Cd(HBINH)(H2O)2Cl2]·1½H2O, [(VO)2(HBINH-3H)(OH)(H2O)] and [Cu2(HBINH-3H)-(H2O)2(OAc)]·3H2O have activities against Bacillus sp. M3010, Candida albicans, Escherichia coli, Staphylococcus aureus and Slamonella sp. PA393.

Synthesis, crystal structure, characterization and biological activity of 2,5-hexanedione bis(isonicotinylhydrazone) and N-(2,5-dimethyl-1H-pyrrol-1-yl)isonicotinamide complexes

The reaction between 2,5-hexanedione and isonicotinic acid hydrazide in EtOH gave two products. The ethanol insoluble product was identified as 2,5-hexanedione bis(isonicotinylhydrazone) [HINH] and the soluble ethanol product as N-(2,5-dimethyl-1H-pyrrol-1-yl)isonicotinamide [DINA]. A series of Cr(3+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Hg(2+) and Pd(2+) complexes of HINH and Co(2+), Cu(2+), Zn(2+) and Hg(2+) complexes of DINA have been synthesized and structurally characterized. Based on the elemental analysis, mass spectra and molar conductance, the complexes have assigned the proposed imperical formulae. The crystal structures of N-(2,5-dimethyl-1H-pyrrol-1-yl)isonicotinamide and its Zn(2+) and Hg(2+) complexes have been solved by X-ray diffraction having [Zn(DINA)2Cl2] and [Hg(DINA)2Cl2] in a tetrahedral structure. In the DINH complexes, the ligand coordinates as a monodentate through the pyridine nitrogen. On the other hand, HINH behaves as a tetradentate (neutral or binegative) manner with the two metal ions. The magnetic moments and electronic spectra of all complexes provide tetrahedral, square-planar, trigonal biyramid and/or octahedral structure. The thermal decomposition of the complexes revealed the outer and inner solvents as well as the end product. The steady part of [Zn(DINA)2Cl2] and [Hg(DINA)2Cl2] thermograms till 303 and 286 °C indicates the absence of any outside solvents. All compounds have activity against bacteria more than fungi. [Cd4(HINH)Cl8]·3H2O has the highest values.

Synthesis, spectral, thermal and biological studies on N(-)(2,4-dinitro-phenyl)-2-mercaptoacetohydrazide and its metal complexes

Complexes of VO(2+), Cr(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+) and Hg(2+) ions with N(-)(2,4-dinitrophenyl)-2-mercaptoacetohydrazide (H2L) have been prepared and characterized on the basis of elemental analysis, molar conductance, thermal (TGA, DTGA), spectral (IR, NMR, UV-Visible, MS) and magnetic measurements. The IR spectra show that H2L behaves in a mononegative and/or binegative bidentate manner. The sulfate bridged the two complex molecules in [Cu(HL)(H2O)2(½SO4)]⋅3H2O. The acetate functions as a monodentate in [Ni(HL)(OAc)(H2O)3] and [Cr(HL)(OAc)2(H2O)(EtOH)]. Different stereochemistries are proposed: octahedral for Cr(III), Ni(II), Hg(II) and [Cu(HL)(H2O)2(SO4)0.5]⋅3H2O, square-based pyramid for [VO(HL)2]⋅EtOH, square-planar for [Co(L)(EtOH)(H2O)]⋅H2O, [Cu(L)(H2O)2] and tetrahedral for [Zn(L)(EtOH)(H2O)], [Cd(L)(EtOH)(H2O)] and [Cu2(HL)(H2O)6]Cl3⋅H2O according to the data of electronic spectra and magnetic measurements. The TGA data support the formula and indicate the outer and inner solvents as well as the final residue. The thermodynamic parameters are calculated using the Coats-Redfern and Horowitz-Metzger methods. H2L and [Zn(L)(EtOH)(H2O)] showed the highest cytotoxic activity while H2L has a higher antioxidant activity than ascorbic acid. The ionization constant of the ligand and the stability constant of the Cu(II)H2L in absence and presence of hexamine buffer were calculated.

An Investigation of a Combined Thiourea and Hexamethylenetetramine as Inhibitors for Corrosion of N80 in 15% HCl Solution: Electrochemical Experiments and Quantum Chemical Calculation

The inhibition mechanism of thiourea (TU) and hexamethylenetetramine (HMTA) mixed in 15% HCl solution on N80 surface was investigated by potentiodynamic polarization, electrochemical impedance spectroscopy measurements, and surface morphology analysis. Quantum chemical calculations and molecular dynamics simulations were performed to study the properties of TU and HMTA. The results showed that the inhibitors can form strong bonds and stable films on the surface, which inhibits the cathodic and anodic reactions in HCl solution and reduces the diffusion coefficients of corrosive particles.