Synthesis, structural characterization, and pro-apoptotic activity of 1-indanone thiosemicarbazone platinum(II) and palladium(II) complexes: potential as antileukemic agents

In the search for alternative chemotherapeutic strategies against leukemia, various 1‐indanone thiosemicarbazones, as well as eight novel platinum(II) and palladium(II) complexes, with the formula [MCl₂(HL)] and [M(HL)(L)]Cl, derived from two 1‐indanone thiosemicarbazones were synthesized and tested for antiproliferative activity against the human leukemia U937 cell line. The crystal structure of [Pt(HL1)(L1)]Cl^.2M eOH, where L1=1‐indanone thiosemicarbazone, was solved by X‐ray diffraction. Free thiosemicarbazone ligands showed no antiproliferative effect, but the corresponding platinum(II) and palladium(II) complexes inhibited cell proliferation and induced apoptosis. Platinum(II) complexes also displayed selective apoptotic activity in U937 cells but not in peripheral blood monocytes or the human hepatocellular carcinoma HepG2 cell line used to screen for potential hepatotoxicity. Present findings show that, in U937 cells, 1‐indanone thiosemicarbazones coordinated to palladium(II) were more cytotoxic than those complexed with platinum(II), although the latter were found to be more selective for leukemic cells suggesting that they are promising compounds with potential therapeutic application against hematological malignancies.     

Synthesis, Spectral and Antibacterial Studies of Copper(II) Tetraaza Macrocyclic Complexes

A novel family of tetraaza macrocyclic Cu(II) complexes [CuLX(2)] (where L = N(4) donor macrocyclic ligands) and (X = Cl(-), NO(3) (-)) have been synthesized and characterized by elemental analysis, magnetic moments, IR, EPR, mass, electronic spectra and thermal studies. The magnetic moments and electronic spectral studies suggest square planar geometry for [Cu(DBACDT)]Cl(2) and [Cu(DBACDT)](NO(3))(2) complexes and distorted octahedral geometry to the rest of the ten complexes. The biological activity of all these complexes against gram-positive and gram-negative bacteria was compared with the activity of existing commercial antibacterial compounds like Linezolid and Cefaclor. Six complexes out of twelve were found to be most potent against both gram-positive as well as gram-negative bacteria due to the presence of thio group in the coordinated ligands.     

Dimethyltin(IV) and palladium(II) complexes derived from 2-benzoylpyridine N(4)-cyclohexylthiosemicarbazone: Synthesis,crystal structures and biological evaluation

Two metal complexes [(Me)₂Sn(L)(OAc)] (1), and [Pd(L)Cl] (2) based on 2-benzoylpyridine N(4)-cyclohexylthiosemicarbazone have been synthesized and structurally characterized. X-ray crystallography reveals that in title compounds, each thiosemicarbazone adopts tridentate NNS manner to coordinate with the metal center, and the metal coordination geometry can be described as a distorted pentagonal bipyramid in 1 and a contorted square-planar in 2, respectively. Growth inhibition assays have indicated that two compounds can effectively inhibit the growth of HepG2 cancer cell lines at micromolar concentrations. In addition, apoptosis mechanisms of 2 on HepG2 cells were further investigated. The results show that 2 can promote the apoptosis of HepG2 cells and the apoptosis is associated with the activation of caspase-3.     

Symmetric 1,1'-Dimethylferrocene-Derived Amino Acids: Their Synthesis, Characterization, Ligational and Biological Properties With Cu(II), Co(II) and Ni(II) Ions

Some novel symmetric 1,1'-dimethylferrocene derived amino acids have been prepared by the reaction of 1,1'-ferrocenedimethyldichloride with amino acids (glycine, alanine, phenylalanine and tyrosine). Their Cu(II), Co(II) and Ni(II) complexes, of the type [M(L)] where [M = Cu(II) and L = L(1)-L(5)] and [M(L)Cl(2)] where [M-Co(II)and Ni(II), L = L(1)-L(5)] have been prepared. The dicarboxylic acids and their metal complexes were characterized by their physical, analytical and spectral data. The [M(L)] complexes showed a square planar geometry whereas an octahedral geometry was observed for [M(L)Cl(2)] complexes. The title dicarboxylic acids and their metal complexes have also been screened for their antibacterial activity.     

Organometallic ruthenium complexes with thiosemicarbazone ligands: Synthesis,structure and cytotoxicity of [(η6-p-cymene)Ru(NS)Cl]+ (NS = 9-anthraldehyde thiosemicarbazones)

A series of half-sandwich arene ruthenium complexes containing bidentate thiosemicarbazone ligands have been synthesized and their biological activity investigated. The compounds have the general formula [(6-p-cymene)Ru(R-ATSC)Cl]X (ATSC = 9-anthraldehyde thiosemicarbazone and R = H, CH₃ and C₆H₅). The crystal structure of [(6-p-cymene) Ru(MeATSC)Cl]Cl have been determined and represents the first structurally characterized arene–ruthenium half-sandwich complex with a thiosemicarbazone ligand. The complexes show good cytotoxic profiles against MCF-7 and MDA-MB-231 (breast adenocarcinoma) as well as HCT 116 and HT-29 (colorectal carcinoma) cell lines.     

Different coordination modes of a tripod phosphine in gold(i) and silver(i) complexes

The following gold(I) and silver(I) complexes of the tritertiary phosphine 1,1,1- tris(diphenylphosphinomethyl)ethane, tripod , have been synthesised: Au(3)(tripod)X(3) [X = Cl(1), Br(2), I(3)]; [Au(3)(tripod)(2)Cl(2)]Cl (4); Au(tripod)X [X = Br(5), I(6)]; Ag(3)(tripod) (NO(3))(4) (7), Ag(tripod)NO(3) (8). They were characterized by X-ray diffraction (complexes 2, 3 and 4), (31)P NMR spectroscopy, electrospray and FAB mass spectrometry and infrared spectroscopy. Complexes 2 and 3 show a linear coordination geometry for Au(I), with relatively short Au-P bond distances. Complex 3 has a Au***Au intramolecular distance of 3.326 A degrees , while complex 2 had a short Au***Au intermolecular interaction of 3.048 A degrees . Complexes 4-6 were found by (31)P NMR spectroscopy studies to contain a mixture of species in solution, one of which crystallised as [Au(3)(tripod|)(2)Cl(2)]Cl which was shown by X-ray diffraction to contain both tetrahedral and linear Au(I), the first example of a Au(I) complex containing such a mixture of geometries. The reaction of [Au(3) (tripod)Cl(3)] (1) with tripod led successfully to the formation of [Au(3)(tripod|)(2)Cl(2)](+) and [Au(3)(tripod)(2)Cl(3)](+) and [Au(3)(tripod|)(3)Cl](2+). The silver(I) complexes, 7 and 8 appear to contain linear and tetrahedral Ag(I), respectively.     

Arene ruthenium(II) p-chloroacetophenone phenylthiosemicarbazone complex mediated transfer hydrogenation of ketones

A series of cationic half-sandwich arene ruthenium(II) complexes of general formula [Ru(η⁶-p-cymene)Cl(L)]Cl have been synthesized from the reaction of [Ru(η⁶-p-cymene)Cl₂]₂ with thiosemicarbazone derivatives (L). Characterization of the complexes were accomplished by analytical and spectral (FT-IR, UV–Vis, ¹H NMR) methods. Single crystal structure determination reveals the presence of a pseudooctahedral three-legged piano stool conformation. All the complexes exhibit a quasi-reversible one electron reduction in the range from ?0.75 to ?0.85 V. Further, the catalytic activity of the titled complex has been investigated in the transfer hydrogenation of ketones in the presence of isopropanol/NaOH.     

Zeolite-encapsulated 2-(o-aminophenyl)benzimidazole complexes: synthesis,characterization and catalytic activity

Cobalt(II), copper(II) and zinc(II) complexes of 2-(o-aminophenyl)benzimidazole (AmPhBzlH) encapsulated in the super cages of zeolite-Y and ZSM-5 have been synthesized and characterized by spectroscopic studies (IR, UV/visible, EPR), elemental analyses, thermal studies and X-ray diffraction patterns. The catalytic activity of encapsulated complexes was investigated for the hydroxylation of phenol using 30% H₂O₂ as an oxidant. Under optimized reaction conditions, the hydroxylation of phenol yielded catechol and hydroquinone as the major products. All catalysts show good selectivity for diphenol products. A maximum conversion of phenol was obtained with [Cu(AmPhBzlH)]-Y as the catalyst. The results showed that conversion of phenol varies in the order [Cu(AmPhBzlH)]-Y > [Cu(AmPhBzlH)]-ZSM-5 > [Zn(AmPhBzlH)]-Y > [Co(AmPhBzlH)]-Y > [Zn(AmPhBzlH)]-ZSM-5 > [Co(AmPhBzlH)]-ZSM-5 after 6 h of reaction time. Test for the recyclability of the reaction was also carried out and the results indicate their recyclability.     

Nitric oxide releasing metal-diazeniumdiolate complexes strongly induce vasorelaxation and endothelial cell proliferation

The preparation, characterization, and NO-releasing properties of metal complexes derived from N-aminoethylpiperazine-N-diazeniumdiolate (HPipNONO), [Cu(PipNONO)Cl] and [Ni(PipNONO)Cl], and the Ni(II) complex derived from the Schiff base between HPipNONO and salicylaldehyde, [Ni(SalPipNONO)], are described. Compounds [Cu(PipNONO)Cl] and [Ni(SalPipNONO)] release NO at a much slower rate than HPipNONO in aqueous buffer in the pH range between 6.8 and 8.0. The kinetics of NO release by [Ni(SalPipNONO)] is complex, with an apparent stepwise release of NO molecules. Both [Cu(PipNONO)Cl] and [Ni(SalPipNONO)] are effective vasorelaxant agents of precontracted rabbit aorta rings, and are active in the nM concentration range. In addition, these complexes promote the proliferation of endothelial cells. Both vascular activities were inhibited by a specific inhibitor of guanylate cyclase, suggesting the involvement of the cGMP pathway. In all biological assays, the reference agent sodium nitroprusside was shown to be 10-1000-fold less potent than the two metal-NONOates.     

Synthesis of imine bond containing insoluble polymeric ligand and its transition metal complexes,structural characterization and catalytic activity on esterification reaction

In this study, synthesis of insoluble polymeric ligand (L) and its transition metal complexes [Cu(L)Cl₂]·2H₂O (1), [Co(L)Cl₂(H₂O)₂] (2) and [Ni(L)Cl₂(H₂O)₂] (3), having the azomethine groups, were synthesized by the condensation reactions of the diamines and dialdehydes. The structural properties were characterized by the analytical and spectroscopic methods using by elemental analysis, Fourier Transform Infrared, Thermo Gravimetric Analysis, Powder X-ray Diffraction, magnetic susceptibility and Inductively Coupled Plasma. The solubilities of the synthesized polymeric materials were also investigated and found as insoluble some organic and inorganic solvents. Additionally, their catalytic performance was carried out for the esterification reaction of acetic acid and butyl acetate. The highest conversion rate is 75.75% by using catalyst 1. The esterification of butanol gave butyl acetate with 100% selectivity.     

1,3,4-thiadiazole derivatives. Part 9. Synthesis and biological activity of metal complexes of 5-(2-aminoethyl)-2-amino-1,3,4-thiadiazole

Metal complexes of the title ligand (L) containing Co(II), Ni(II) and Cu(II) were prepared and characterized by elemental analysis, IR, electronic spectroscopy and conductimetry. The new derivatives, possessing the following formulae, CuL(2)(OH)(2), NiL(2)Cl(2), and [Co(2)LCl(4)](n) showed in vitro antifungal activity against Aspergillus and Candida spp.     

SOD mimic activity,DNA binding and in-vitro antibacterial studies of drug based copper(II) complexes

Square pyramidal complexes [Cu^II(PFL)(bpa)Cl]?5H₂O (1) and [Cu^II(LFL)(bpa)Cl]?5H₂O (2) have been synthesized and characterized. Compounds were checked for their in-vitro antimicrobial activity against two Gram^(+ ve) and three Gram^(–ve) bacterial species. Intrinsic binding constant (K_b) of complexes with CT DNA were determined using absorption titration. Viscosity measurement suggests that complexes bind with CT DNA through partial nonclassical intercalative mode. Superoxide dismutase (SOD) like activity of the complexes was also compared with previously reported compounds.     

Host (nanopores of zeolite Y)-guest (oxovanadium(IV) tetradentate schiff-base complexes) nanocomposite materials: synthesis,characterization and liquid phase hydroxylation of phenol with hydrogen peroxide

Oxovanadium(IV) tetradentate Schiff-base complexes; [VO(X₂-haacac)] (X = H, Cl, CH₃ and NO₂), X₂-haacac = substituted bis(2-hydroxyanil)acetylacetone; and encapsulated in the nanopores of zeolite NaY; [VO(X₂-haacac)]-NaY; have been synthesized and characterized. The host-guest nanocomposite materials; [VO(X₂-haacac)]-NaY; was characterized by chemical analysis and spectroscopic methods (FT-IR, UV/VIS, XRD, BET and DRS). The analytical data indicated a composition corresponding to the mononuclear complex of Schiff-base ligand. The characterization data showed the absence of extraneous complexes, retention of zeolite crystalline structure and encapsulation in the nanopores. Substitution of the aromatic hydrogen atoms of the Schiff-base ligand by electron withdrawing groups like −Cl, and −NO₂ has two major effects: (1) retention and concentration of the oxovanadium(IV) complex in the zeolite cavities is enhanced (due to the larger size of the substituents) and (2) the electronic and spectral properties of the encapsulated complex are modified. Liquid-phase selective hydroxylation of phenol with H₂O₂ to a mixture of catechol and hydroquinone in CH₃CN has been reported using oxovanadium(IV) Schiff-base complexes encapsulated in zeolite-Y as catalysts. Reaction conditions have been optimized by considering the concentration of substrate and oxidant, amount of catalyst, effect of time, volume of solvent and temperature. Under the optimized reaction conditions, [VO((NO₂)₂-haacac)]-NaY has shown the highest conversion of 42.3% after 6 h. All these catalysts are more selective toward catechol formation. Encapsulated oxovanadium(IV) complex is catalytically very efficient as compared to other neat complexes for the hydroxylation of phenol and is stable to be recycled without much deterioration.     

Synthesis,characterization, and catalytic study of polymeric metal complexes derived from divalent transition metal ions with 2,4‐dihydroxy benzophenone and 2,4‐dihydroxy acetophenone

The polymeric metal complexes of poly (3‐hydroxy‐4‐((Z)‐1‐(phenylimino)ethyl)phenyl‐3‐methylbut‐2‐enoate) designated as [poly(3H4‐1PEPMB)] and poly (3‐hydroxy‐4‐((Z)‐phenyl(phenylimino)methyl)phenyl‐3‐methylbut‐2‐enoate designated as [poly(3H4‐PPMPMB)] containing Cu(II), Ni(II), Co(II), Cd(II), Mn(II), Ca(II), and Zn(II) ions were synthesized. The ploymer ligands and metal complexes were charcterized by Fourier transform infrared, nuclear magnetic resonance (NMR), thermogravimetric analysis, differential scanning calorimeter (DSC), and X‐ray diffraction (XRD) techniques. The XRD study of the complexes revealed highly crystalline nature of polychelates. The polymeric complexes were active for the oxidation of aldehyde group. The oxidation activity of Cu (II) complex of poly (3H4‐1PEPMB) was studied for the oxidation of benzaldehyde and its derivaties to corresponding carboxylic acids. The oxidation products were confirmed by GC‐MS analysis. The oxidation of aldehydes was quantitative with 100% selectivity for benzioc acid. Thermal analysis of complexes indicated reasonably good thermal stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Toxicity, Spectroscopic Characterization and Electrochemical Behaviour of New Macrocclic Complexes of Lead(II) and Palladium(II) Metals

Tetraazamacrocyclie complexes of lead and palladium have been synthesized by the template process using the bis(benzil)ethylenediamine precursor. The tetradentate macrocycle (maL) reacts with PbCl(2), PdCl(2) and different diamines in a 1:1:1 molar ratio in methanol to give several solid complexes of the types [Pb(maL)(R)Cl(2)] and [Pd(maL)(R)]Cl(2) (where R = 2,6-diaminopyridine or 1,2-phenylenediamine). The macrocycle and its metal complexes have been characterized by elemental analysis, molecular weight determinations, molar conductivity, IR, (1)H NMR, (13)C NMR, electronic, mass and electrochemical studies. The macrocyclic ligand coordinates through the four azomethine nitrogen atoms which are bridged by benzil moieties. IR spectra suggest that the pyridine nitrogen is not coordinating. The palladium complexes exhibit tetracoordinated square-planar geometry, whereas a hexacoordinated octahedral geometry is suggested for lead complexes. The macrocycle along with its complexes have been screened in vitro against a number of pathogenic fungi and bacteria to assess their growth inhibiting potential.     

克霉唑金属配合物的合成与表征

以无水甲醇为溶剂,以克霉唑为配体分别与二水合氯化铜、无水氯化锌反应,合成了2种新的药物金属配合物。化合物经元素分析、摩尔电导率、IR、TG及UV等分析表征,表明2种配合物的可能结构式为:[Cu(C22H17ClN2)C l2]n,[Zn(C22H17ClN2)2Cl2]。     

Zeolite encapsulated Ru(III), Cu(II) and Zn(II) complexes of benzimidazole as reusable catalysts for the oxidation of organic substrates

Ru(III), Cu(II) and Zn(II) complexes of benzimidazole (BzlH) have been synthesized in the supercages of zeolite-Y by the flexible ligand method and were characterized by spectroscopic (IR, UV–Vis and ESR) studies, XRD and thermogravimetric analysis, surface area, and pore volume measurements. The zeolite encapsulated complexes catalyzed the oxidation of ethylbenzene, benzoin, and cyclohexanol. Various parameters, such as concentration of oxidant and catalyst, reaction time, temperature of the reaction and type of solvents have been optimized to obtain the maximum transformation of ethylbenzene to a mixture of acetophenone, benzaldehyde and styrene. Under the optimized reaction conditions, [Ru(BzlH)]-Y gave 80.4 % conversion of ethylbenzene in 1 h. All these zeolite encapsulated complexes were more selective towards acetophenone formation. Oxidation of benzoin catalyzed by [Cu(BzlH)]-Y, [Ru(BzlH)]-Y and [Zn(BzlH)]-Y encapsulated complexes resulted in 75.5, 78.7 and 59.9 % conversion respectively to give benzaldehyde as exclusive product. A maximum conversion of 39.1 % cyclohexanol with [Cu(BzlH)]-Y was achieved to give cyclohexanone. The activity of neat complexes towards these reactions was also carried out. The encapsulated catalysts were significantly more active than neat complexes and recyclable without much loss in catalytic activity.     

Synthesis,Characterization, Cytotoxicity and Detailed HSA Interaction of New Zinc(II) Complexes Containing Dithiocarbamate and Heterocyclic N-donor Ligands

[Zn(ph-dtc)(bpy)]Cl (1) and [Zn(ph-dtc)(phen)]Cl (2) (where bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline and ph-dtc = phenylacetichydrazidedithiocarbamate) were synthesized and characterized by elemental analysis and spectroscopic methods (FT–IR, UV–Vis and ¹H NMR). Zn(II) complexes were examined in biological tests in vitro using MCF-7 breast cancer cell line. Both complexes showed significant cytotoxic activity against human breast cancer MCF-7 cells. The interaction of above compounds with Human Serum Albumin (HSA) was investigated by means of various spectroscopic (at pH ～ 7.4 in Tris–HCl buffer medium) and molecular docking methods. The fluorescence data showed that 1 and 2 quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding constants (K_b) and the number of binding sites (n ～ 1) were calculated. The thermodynamic analysis suggested that hydrophobic interaction played major roles in the binding of 1 or 2 to HSA. The distance r between protein and the above-mentioned compounds was obtained according to fluorescence resonance energy transfer. The conformational changes of protein secondary structure in the presence of Zn(II) complexes were proven using UV–Vis absorption and circular dichroism techniques. Also, docking results confirmed the spectroscopic results.     

DNA binding,cytotoxicity and DNA cleavage promoted by gold(III) complexes

Square planar Au(III) complexes of 2,2′-dipyridylamine (A¹), di(2-pyridyl)ketone (A²), 2-(4-chlorophenyl)-1H-imidazo[4,5-f] [1,10] phenanthroline (A³) and 2-(4-bromophenyl)-1H-imidazo[4,5-f][1,10] phenanthroline (A⁴) of type [Au(Aⁿ)Cl₂].Cl were synthesized and characterized using conductivity measurement, C,H,N elemental analysis, FT-IR, LC–MS, ¹H and ¹³C NMR spectroscopy. The compounds manifested significant cytotoxic properties in vitro for brine shrimp lethality bioassay. The metal complexes were screened for series of DNA binding activity using UV–vis. absorption titration, hydrodynamic measurement and thermal DNA denaturation study. The nucleolytic activity was performed on plasmid pUC19 DNA. The Michaelis–Menten kinetic studies were performed to evaluate rate of enhancement in metal complexes mediated DNA cleavage over the noncatalyzed DNA cleavage.     

Synthesis, characterisation and biological activity of thienoyl- and furanoyl-derived schiff-base compounds with 3d metal ions

Cobalt(ll), copper(ll), nickel(ll) and zinc(ll) metal complexes of 2-carboxybenzylidene thienoylhydrazide HL(1) and 2-carboxybenzylidene furenoylhydrazide HL(2) of the type [M(L)(2).Cl(2)] have been prepared where M = Co(ll) and Ni(ll) and L = HL(1) and HL(2) (Fig 1) and characterized by their physical, analytical and spectral studies. The different mode of chelation of the ligands with metals and the effect of these metals on their biological properties is discussed.