Synthesis and spectroscopic studies of some cadmium(II) and mercury(II) complexes of an asymmetrical bidentate Schiff base ligand

In vitro nephrotoxicity and anticancer potency of newly synthesized cadmium complexes

Complexes based on heavy metals have great potential for the treatment of a wide variety of cancers but their use is often limited due to toxic side effects. Here we describe the synthesis of two new cadmium complexes using N(4)-phenyl-2-formylpyridine thiosemicarbazone (L1) and 5-aminotetrazole (L2) as organic ligands and the evaluation of their anti-cancer and nephrotoxic potential in vitro. The complexes were characterized by Single-crystal X-ray data diffraction, 1HNMR, FT-IR, LC/MS spectrometry and CHN elemental analysis. Next, cytotoxicity of these cadmium complexes was evaluated in several cancer cell lines, including MCF-7 (breast), Caco-2 (colorectal) and cisplatin-resistant A549 (lung) cancer cell lines, as well as in conditionally-immortalized renal proximal tubule epithelial cell lines for evaluating nephrotoxicity compared to cisplatin. We found that both compounds were toxic to the cancer cell lines in a cell-cycle dependent manner and induced caspase-mediated apoptosis and caspase-independent cell death. Nephrotoxicity of these compounds was compared to cisplatin, a known nephrotoxic drug, in vitro. Our results demonstrate that compound {2}, but not compound {1}, exerts increased cytotoxicity in MCF-7 and A549 cell lines, combined with reduced nephrotoxic potential compared to cisplatin. Together these data make compound {2} a likely candidate for further development in cancer treatment.

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.

Chelation, spectroscopic characterization, biological activity and crystal structure of 2,3-butanedione isonicotinylhydrazone: Determination of Zr(4+) after flotation separation

New metal complexes of Co(II), Ni(II) Cu(II), Zn(II), Cd(II), Pd(II) and Hg(II) with 2,3-butanedione isonicotinylhydrazone [BINH] have been prepared and investigated. Single crystal for BINH is grown and solved as orthorhombic with P 21 21 2 space group. The formula of the ligand was assigned based on the elemental analysis, mass spectra and conductivity measurements. The complexes assigned the formulae [M(BINH-H)Cl]⋅nH2O (MCo(II), Ni(II), Cu(II), Zn(II); n=0 or 1); [Hg(BINH-H)(H2O)2Cl]; [Cd(BINH)Cl2]⋅2H2O and [Pd(BINH)Cl2]⋅H2O. All complexes are nonelectrolytes. BINH acts as a tridentate ligand in [M(BINH-H)Cl]⋅nH2O and [Hg(BINH-H)(H2O)2Cl] coordinating through COketonic, COamedic and CNhy and as a neutral bidentate through COketonic and CNhy in [Cd(BINH)Cl2]⋅2H2O and [Pd(BINH)Cl2]⋅H2O; the pyridine nitrogen has no rule in coordination. The data are supported by NMR ((1)H and (13)C) spectra. The magnetic moments and electronic spectra provide a tetrahedral structure for the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes; square-planar for the Pd(II) complex and octahedral for the Hg(II) complex. The TGA of the complexes depicted the outer and inner water molecules as well as the final residue. The cobalt and cadmium complexes ended with the metal while the Cu(II), Zn(II) and Pd(II) complexes ended with complex species. [Hg(BINH-H)(H2O)2Cl] has no residue. The ligand is inactive against all tested organisms except for Bacillus thuringiensis. The Hg(II) complex is found more active than the other complexes. The flotation technique is found applicable for the separation of micro amount (10ppm) of Zr(4+) using 10ppm of BINH and 1×10(-5)molL(-1) of oleic acid at pH 6 with efficiency of 98% with no interferences.

Spectroscopic characterization and biological activity of dihydrazone transition metal complexes: crystal structure of 2,3-butanedione bis(isonicotinylhydrazone)

Metal complexes of the chloride, nitrate and acetate salts of Co(II), Ni(II) Cu(II), Zn(II), Cd(II) or Hg(II) with 2,3-butanedione bis(isonicotinylhydrazone) [BBINH] have been synthesized and structurally characterized. The crystal of BBINH was solved to crystallize as monoclinic system with space group of P121/c14. The formulae of the complexes were assigned based on the elemental analysis and mass spectra. The formation of BBINH complexes depend on the metal anion used. All complexes are nonelectrolytes except for the complexes 2, 3, 4 are (1:1) and 13 and 14 which are 1:2 electrolytes. BBINH behaves as a neutral tetradentate (N2O2) in the chloride complexes of Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II). In [Co2(BBINH)(H2O)Cl3]Cl⋅H2O, BBINH has the same dentate but with the two Co(II) ions. In the acetate complexes, [Ni2(BBINH-2H)(H2O)2(OAc)2]⋅3H2O and [Cu2(BBINH-2H)(OAc)2]⋅5H2O, BBINH acts as a binegative tetradentate with the two metal ions. The ligand in the nitrate complexes acts as a neutral bidentate via the two hydrazone azomethine C=NHy; the nitrate ions are ionic in the Cd(II) and Zn(II) complexes and covalent in the Ni(II) complex. The data are supported by NMR ((1)H and (13)C) spectra. The magnetic moments and electronic spectra of all complexes provide tetrahedral, square planar and/or octahedral structure. The decomposition of the complexes revealed the outer and inner solvents as well as the remaining residue based on TGA. The complexes have variable activities against some bacteria and fungi. The ligand is inactive against all tested organisms. The activity of Cd(II) and Hg(II) may be related to the geometry of the complexes.

Crystal growth and characterization of an organic nonlinear optical single crystal: 2,3-Dimethyl-N-[4-(Nitro) benzylidene] aniline

An organic nonlinear optical material 2,3-Dimethyl-N-[4-(Nitro) benzylidene] aniline was synthesized by condensation reaction. The single crystals were grown by the slow evaporation technique at room temperature using ethyl acetate as solvent with large in size and having transparent nature. The unit cell parameters were determined and belong to a noncentrosymmetric orthorhombic crystal structure by single crystal X-ray diffraction. The crystalline nature of the synthesized material was recorded by the powder X-ray diffraction pattern. The molecular structure of the grown material was investigated by proton and carbon nuclear magnetic resonance, mass spectrum analysis. Functional groups were identified by the vibration spectrum analysis. The optical absorbance of the grown crystal was ascertained by Ultraviolet-Visible spectrum. Thermal behaviour and stability of the grown material was investigated by thermo gravimetric/differential thermal analysis. The nonlinear optic conversion efficiency was determined by powder technique and found to be 4.08 times greater that of KDP as a standard reference.

Two 2D Cd(II) coordination polymers based on asymmetrical Schiff-base ligand: synthesis, crystal structures and luminescent properties

Two new two-dimensional coordination polymers [Cd(3)L(2)(SCN)(6)](n) (1) and [CdLI(2)](n) (2) have been synthesized and characterized by IR spectroscopy, elemental analysis, TG technique, XRPD and complete single crystal structure analysis, where L is 4-(pyridine-2-yl)methyleneamino-1,2,4-trizaole. Asymmetrical Schiff-base ligand L with five- and six-membered N-containing heterocyclic rings acts as a tridentate bridging ligand to bind two Cd(II) centers through one terminal N(triazolyl) and one pyridylimine chelate unit in 1 and 2. For polymer 1, tridentate bridging ligands link Cd-(1,3-μ-SCN(-)) 1D inorganic chains to form a 2D layer network. The existence of C-H···π and π-π stacking interactions between 2D hybrid layers further gives rise to a 3D supramolecular network. In comparison with 1, polymer 2 shows a 2D layer network containing hexanuclear macrometallacyclic units. The 2D layers are staggered together through the combination of C-H···π and π-π stacking interactions and forming a 3D supramolecular structure. The luminescent properties of the polymers 1 and 2 were investigated in the solid state at room temperature.

Synthesis, spectral identification, electrochemical behavior and theoretical investigation of new zinc complexes of bis((E) 3-(2-nitrophenyl)-2-propenal)propane-1,2-diimine

Synthesis, spectroscopic, electrochemical behavior and theoretical investigation of some zinc complexes of a new Schiff base ligand of bis((E) 3-(2-nitrophenyl)-2-propenal)propane-1,2-diimine (L) with a general formula of ZnLX(2)(X=Cl(-), Br(-), I(-), SCN(-) and N(3)(-)) are described. The ligand and its complexes were identified by elemental analysis, molar conductivity, UV-Visible spectra, FT-IR spectra, (1)H NMR and (13)C NMR spectra. The complexes were found to be molecular and non-electrolyte based on conductivity measurement. The spectral data confirm coordination of ligand and anions(X(-)) to zinc ion center. Electrochemical behavior of ligand and complexes were investigated by cyclic voltammetry technique exhibiting different redox behavior of complexes with respect to free ligand so that the ligand and complexes showed quasi-reversible and irreversible electron transfer processes respectively. Molecular structures of the ligand and complexes have been optimized at the UB3LYP/LANL2MB(*) level of theory. Accordingly some theoretical thermodynamical and/or structural parameters such as HF-energy, Gibbs free energy, enthalpy, selected bond distances, bond angles and torsion angles of optimized structures are presented.

Investigations on growth and crystalline perfection of an organic Schiff base material: 4-chloro-4'bromobenzylidene aniline

Single crystal of an organic material, 4-chloro-4'bromobenzylidene aniline (CBBA), was synthesized and grown by slow evaporation method at room temperature. (1)H and (13)C NMR spectra were recorded to elucidate the molecular structure and functional groups of CBBA were identified using FTIR and FT Raman spectral analyses. The lattice parameters were calculated from single crystal X-ray diffraction data. Single and reasonably sharp peak observed in the high resolution X-ray diffraction curve indicates that the quality of the crystal is good. Thermal properties of CBBA were carried out using thermogravimetric, differential thermal and differential scanning calorimetric analyses and the melting point of the CBBA material is ~123 °C. The dielectric properties of CBBA crystal was studied as the function of frequency (100 Hz-500 kHz). The optical properties were ascertained by recording UV-vis-NIR and fluorescence spectrum. Further the mechanical properties were studied using Vickers microhardness test.

Synthesis and spectroscopic studies of 2,5-hexanedione bis(isonicotinylhydrazone) and its first raw transition metal complexes

New VO(2+), Mn(2+), Co(2+), Ni(2+) Cu(2+) and Zn(2+) complexes of 2,5-hexanedione bis(isonicotinylhydrazone) [H(2)L] have been synthesized and characterized. The analyses confirmed the formulae: [VO(L)].H(2)O, [Mn(2)(H(2)L)Cl(2)(H(2)O)(6)]Cl(2), [Co(L)(H(2)O)(2)].2H(2)O, [Ni(HL)(OAc)].H(2)O, [Cu(L)(H(2)O)(2)].2H(2)O, [Cu(L)].2H(2)O and [Zn(L)(H(2)O)(2)]. The formulae of [Ni(HL)(OAc)].H(2)O, [Zn(L)(H(2)O)(2)] and [Mn(2)(H(2)L)Cl(2)(H(2)O)(6)]Cl(2), are supported by mass spectra. The molecular modeling of H(2)L is drawn and showed intramolecular hydrogen bonding. The ligand releases two protons during reaction from the two amide groups (NHCO) and behaves as a binegative tetradentate (N(2)O(2)); good evidence comes from the (1)H NMR spectrum of [Zn(L)(H(2)O)(2)]. The ligand has a buffering range 10-12 and pK's of 4.62, 7.78 and 9.45. The magnetic moments and electronic spectra of all complexes provide a square-planar for [Cu(L)].2H(2)O, square-pyramidal for [VO(L)].H(2)O and octahedral for the rest. The ESR spectra support the mononuclear geometry for [VO(L)].H(2)O and [Cu(L)(H(2)O)(2)].2H(2)O. The thermal decomposition of the complexes revealed the outer and inner solvents where the end product in most cases is metal oxide.