Shahab A.A. Nami

Template synthesis of symmetrical transition metal dithiocarbamates

Novel transition metal dithiocarbamates of the type [M2(etdtc)2] and [M1(etdtc)Cl]2 where M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II), M1 = Cr(III), Fe(III) and etdtc = (S4N4C11H18 ) have been synthesized by the use of self-assembly techniques. The metal dithiocarbamates were prepared from the primary amine, CS2 and metal chloride. They have been characterized by spectroscopic, TGA/DSC, magnetic susceptibility and conductivity data. The complexes, [Mn2(etdtc)2], [Fe2(etdtc)2], [Co2(etdtc)2], [Zn2(etdtc)2], [Cd2(etdtc)2] and [Hg2(etdtc)2] have been suggested to be tetrahedral while [Ni2(etdtc)2] and [Cu2(etdtc)2] have square-planar geometry. [Cr(etdtc)Cl]2 and [Fe(etdtc)Cl]2 have chlorine bridged distorted-octahedral geometry. It has been observed that the dithiocarbamato moiety is symmetrically bonded in all the cases. A three stage TGA profile is observed for all the complexes leading to the formation of respective metal sulfide as the end-product. The molar conductance of 10-3 mol L-1 solution of the complexes measured in DMSO is indicative of their non-ionic nature.

Synthesis and characterization of transition metal 2,6-pyridinedicarboxylic acid derivatives, interactions of Cu(II) and Ni(II) complexes with DNA in vitro

Mononuclear complexes M(L)Cl(2) where M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II) and (L=N,N-diethylpiperazinyl,2,6-pyridinedicarboxylate), have been synthesized and characterized by elemental analysis, FT-IR, (1)H NMR spectroscopy, UV-vis, magnetic moment, TGA/DSC, cyclic voltammetry and conductivity measurement data. The spectral data suggests that the dipicolinic acid acts as a bidentate ligand and is coordinated to the metal ion through the carboxylate oxygen. The cyclic voltammogram for Cu(L)Cl(2) complex was found to display two reversible Cu(II)/Cu(I) and Cu(II)/Cu(III) redox couple. The ligand exhibits a two-step thermolytic pattern while the complexes decompose in three stages respectively. An octahedral geometry has been proposed for both the complexes. The investigation of the interaction of the complexes with calf thymus DNA has been performed with absorption spectroscopy and fluorescence quenching experiments, which showed that the complexes are avid binders of calf thymus DNA. Also the interaction of the Cu(II) and Ni(II) complexes with plasmid DNA (pUC 19) was studied using agarose gel electrophoresis. The results revealed that these complexes can act as effective DNA cleaving agents resulting in the nicked form of DNA (pUC 19) under physiological conditions. The gel was run both in the absence and presence of an oxidizing agent (H(2)O(2)). The ligand and its complexes have also been screened against microbes in order to study their antibacterial action. The results revealed that the Cu(II) complex has activity comparable with the reference drugs gentamycin and flucanzole.

Synthesis, characterization and antifungal activities of 3d-transition metal complexes of 1-acetylpiperazinyldithioc arbamate, M(acpdtc)2

A series of mononuclear 3d-transition metal complexes of the type M(acpdtc)2 have been synthesized (where acpdtc=1-acetylpiperazinyldithiocarbamate, M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II)). The ligand and its complexes have been characterized by micro analysis (CHNS), TG/DSC, FT-IR, UV-vis, 1H NMR, magnetic susceptibility and conductance measurements. On the basis IR spectroscopy a symmetrical bidentate coordination has been observed for the 1-acetylpiperazinyldithiocarbamate moiety in all the complexes. On the basis of UV-vis spectra and magnetic susceptibility measurement a square-planar geometry has been proposed for the Ni(II) and Cu(II) complexes while the other complexes have been found to acquire a distorted-tetrahedral structure. The thermogravimetric and differential scanning calorimetric profile of the ligand indicates a two-step decomposition pattern while the complexes exhibit a three-stage thermogram forming metal sulfide as the eventual end product. The molar conductivity data of 1mM solution in DMSO of the complexes is in close accord to their non-electrolytic behaviour. The ligand and its 3d-transition metal complexes have also been tested for their antifungicidal activity by agar well diffusion method using Fusarium sp. and Sclerotina sp. The maximum activity has been observed in case of Mn(II) and Fe(II) complexes.

Convenient One-Pot Synthesis of Symmetrical Dithiocarbamates

Abstract Self‐assembled symmetrical metal dithiocarbamates of the type M2(hdtc), where [M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) and hdtc = (S2N2C3H4)2CH2] with a closed‐ring system, have been synthesized by a convenient one‐pot synthesis in moderate yields. Based on elemental analyses, IR, TGA, and magnetic susceptibility measurements, a square‐planar geometry has been proposed for the Co(II), Ni(II), and Cu(II) dithiocarbamates, while the Zn(II), Cd(II), and Hg(II) complexes have been suggested to have a tetrahedral geometry. It has been observed that the dithiocarbamato moiety is symmetrically bonded to the metal ion via both sulfur atoms of the –NCS2 group. Since the dithiocarbamates are covalently bonded to the metal ions they are non‐conducting in solution.

Synthesis, Characterization and Thermal Studies of Bipyridine Metal Complexes Containing Different Substituted Dithiocarbamates

Complexes of the type [Mpy2(dedtc)2], and [Mpy2(dpdtc)2], where M=Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), py=pyridine, dedtc=diethyldithiocarbamate and dpdtc=diphenyldithiocarbamate, have been synthesized and characterized by elemental analyses, magnetic susceptibility, TGA/DSC and IR in the solid-state, and electronic spectroscopy and conductivity measurement studies in solution. The dithiocarbamato moiety has been found to be symmetrically bonded to the metal. The complexes are proposed to have a distorted-octahedral structure. The ligand field parameters 10 Dq, B and β have also been evaluated. The value of β indicates a considerable orbital overlap in the complexes. A two-stage decomposition pattern leading to the formation of respective metal sulfide as the end-product has been observed in all the complexes. Their molar conductance indicated them to be non-electrolyte in nitrobenzene.

Synthesis, characterization, thermal and antioxidant studies of potassium dihydrobisphenothiazinyl borate and its transition metal complexes

The bidentate borate anion H(2)B(ptz)(2)(-) and its transition metal complexes have been synthesized and characterized by elemental analyses, magnetic susceptibility, electronic, IR, (1)H and (13)C NMR data. The molar conductance of 10(-3) M solution for all the complexes supports their non-ionic nature. The TGA profile of borate anion shows a single stage unlike that of two stage decomposition plot of the metal complexes. On the basis of spectroscopic studies the geometry of all the complexes have been proposed to be distorted-tetrahedral. The in vitro antioxidant and lipid oxidation inhibition of the ligand and its complexes have also been studied. The Cu[B(ptz)(2)](2) complex was found to be most effective in all the studies.

Herbo-mineral based Schiff base ligand and its metal complexes: Synthesis, characterization, catalytic potential and biological applications.

Schiff base ligand, (L), derived from condensation reaction of 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, (curcumin), with pyridine-3-carboxamide, (nicotinamide), and its complexes of Co(II), Ni(II) and Cu(II) ions, containing 1,10-phenanthroline as auxiliary ligand were synthesized and characterized by various physico-chemical techniques. From the micro analytical data, the stoichiometry of the complexes 1:1 (metal: ligand) was ascertained. The Co(II) and Cu(II) forms octahedral complexes, while the geometric structure around Ni(II) atom can be described as square planar. The catalytic potential of the metal complexes have been evaluated by recording the rate of decomposition of hydrogen peroxide. The results reveal that the percent decomposition of H2O2increases with time and the highest value (50.50%) was recorded for Co(II) complex. The ligand and its complexes were also screened for their in vitro antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pyogenes and Pseudomonas aeruginosa. The relative order of antibacterial activity against S. Pyogenes, S. aureus and E. coli is Cu(II)>Ni(II)>Co(II)>(L); while with P. aeruginosa, K. pneumoniae the order of activity is Cu(II)>Co(II)>Ni(II)>(L). The anthelmintic screening was performed using Pheretima posthuma. The order of anthelmintic activity of ligand and its complexes is [(Phen)CuLCl2]>[(Phen)CoLCl2]>[(Phen)NiL]Cl2>(L).

Self assembled homodinuclear dithiocarbamates: One pot synthesis and spectral characterization

Several self assembled homodinuclear complexes of the type [M2(Ldtc)2·4H2O] derived from quadridentate ligand (Ldtc), where Ldtc = 2-aminobenzoylhydrazidebis(dithiocarbamate) and M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) have been reported. The in situ procedure gives high yield with the formation of single product as evident by TLC and various other physicochemical techniques. Elemental analysis, TGA, (1)H NMR, (13)C NMR, ESI mass spectrometry, EPR, UV-vis. and IR spectroscopy were used to characterize the homodinuclear complexes. The spectroscopic evidences and room temperature magnetic moment values suggest that all the complexes have octahedral geometry around the transition metal atom. A symmetrical bidentate coordination of the dithiocarbamato moiety has been observed in all the complexes. The energy-minimized structure of the molecule also showed that each metal atom acquires a distorted octahedral geometry. The complexes exhibit a three-step thermolytic pattern and are non-electrolyte in nature.

Synthesis, crystal structure, and magnetic properties of single end-to-end azido-bridged 1-D chain coordination polymers of Cu(II)

The synthesis and spectroscopic characterization of azido derivatives of Cu(II) complexes with macrocyclic building blocks of the type [CuLN3] n  · [ClO4 · 3/2H2O] n (1), [CuL(N3)2] (2) and [CuL1N3]n · [ClO4]n (3) (where L = 3,10-bisbenzyl-1,3,5,8,10,12-hexaazacyclotetradecane and L1 = 3,10-bisbenzyl-6,13-dimethyl-1,3,5,8,10,12-hexaazacyclotetradecane) are reported. On the basis of single-crystal X-ray diffraction, 1 and 3 have a 1-D polymeric chain where Cu(II) ions are bridged by single azide in the μ-1,3 (end-to-end) bridging mode in a trans-position with respect to the azide. When [CuLN3] n  · [ClO4 · 3/2H2O] n was recrystallized from acetone, the non-polymeric 2 was obtained, where Cu(II) is in a tetragonally distorted octahedral environment. The chains of [CuLN3] n  · [ClO4 · 3/2H2O] n and [CuL1N3] n  · [ClO4] n propagate parallel to the crystallographic b-axis and are stacked one over the other along the c-axis by hydrogen bonding. The azides exhibit symmetric coordination. The ions fill channels formed between the strings of octahedra and are held in place by hydrogen bonds leading to the formation of a 3-D network. Compound 1 exhibits only very weak antiferromagnetic interactions, while 2 and 3 show no signs of magnetic exchange.

Synthesis, Spectral Characterization, and In Vitro Cytotoxicity of N-2′-Hydroxyethyl-Substituted Azacholestanes Prepared from 6-Oxocholestanes by Modified Schmidt Reaction

The present paper reports the synthesis and spectroscopic characterization of few N-2′-hydroxyethyl-substituted azacholestanes using BF3-OEt2, TiCl4, SnCl4, and H2SO4 as catalysts in moderate yields by a modified version of Schmidt reaction. A notable feature is the passivity of SnCl4 in case of 3β-acetoxy-N-2′-hydroxyethyl-6-aza-B-homo-5α-cholestan-7-one and 3β-chloro-N-2′-hydroxyethyl-6-aza-B-homo-5α-cholestan-7-one. However, the reaction was unsuccessful in case of N-2′-Hydroxyethyl-6-aza-B-homo-5α-cholestan-7-one. Another striking aspect is the attainment of high yield in case of H2SO4 as catalyst. The semisolid compounds are characterized using various spectroscopic techniques such as FT-IR, 1H-NMR and mass spectra, and microanalytical data. A reaction mechanism has been proposed on the basis of previous studies. Moreover, the compounds have also been screened for their in vitro cytotoxicity against human colon carcinoma cell line, HCT116, and human liver hepatocellular carcinoma cell line, HepG2, using doxorubicin as standard. On the basis of IC50 values, 3β-chloro-N-2′-hydroxyethyl-6-aza-B-homo-5α-cholestan-7-one (5) was found to inhibit the cancer cells most effectively.