Synthesis and "in Vitro" Trypanocidal Activity Evaluation of Some Organo-iron Compounds

Eight organo-iron ferrocene derivatives and arenocenium salts were prepared and evaluated by "in vitro" assay against one strain of Trypanosoma cruzi (Y). Six of the eight organo-iron compounds assayed, piperazinium diferrocenoate 1, eta(6)-(o-xylene)-eta(5)-(cyclopentadienyl) Iron(II) hexafluorophosphate 3, eta(6)-(mesitylene)-eta(5)-(cyclopentadienyl) iron(II) hexafluorphosphate 5, eta(6)-(durene)-eta(5)-(cyclopentadienyl) iron(II) hexafluorphosphate 6, eta(6)-(rho-chlorotoluene)-eta(5)-(cyclopentadienyl) Iron(II) hexafluorphosphate 7 and eta(6)-(chlorobenzene)-eta(5)-(cyclopentadienyl) iron(II) picrate 8 , were poorly active in the "in vitro" assays. Only two compounds 1,1'-(N-pyperidinocarbonyl) ferrocene 2(IC(50)=2.4 mug/mL) and eta(6)-(o-xylene)-eta(5)(cyclopentadienyl) iron(II) picrate 4 (IC(50)=12.08 mug/mL), were more active. Thus, some of the compounds are promising to be used against Chagas' disease as a prophylactic agents.     

Antibacterial and Antifungal Activity of Zinc(II) Carboxylates With/Without N-Donor Organic Ligands

The antibacterial and antifungal activity of zinc(II) carboxylates with composition Zn(RCOO)(2)*nH(2)O(R =H-, CH(3) (-), CH(3)CH(2)CH(2) (-), (CH(3))(2)CH-, XCH(2) (-), X=Cl, Br, I, n=0 or 2), [ZnX(2)(Nia(+)CH(2)COO(-))(2)](Nia=nicotinamide, X=Cl, Br, I) and [Zn(XCH(2)COO)(2)(Caf)(2)]*2H(2)O (Car=caffeine, X=Cl, Br) is studied against bacterial strains Staphylococcus aureus, Escherichia coli and yeast Candida albicans. The structural types are assigned to the prepared compounds and the influence of (i) carboxylate chain length, (ii) substitution of hydrogen atom of carboxylate by halogen and (iii) presence of N-donor organic ligands on the biological activity is discussed.     

Structure Determination and Anti-Inflammatory Activity of some Purine Complexes

Organomercury(II)-purine derivatives of the type, p-MeOC(6)H(4)HgL(1) (I), p-NO(2)C(6)H(4)HgCl(L(2))(II), p-MeC(6)H(4)HgCl(L(3))(III) and p-NO(2)C(6)H(4)HgCl(L(3))(IV) [ HL(1) = theophylline, L(2) = theobromine, L(3) = caffeine] have been synthesised and characterised on the basis of spectral studies (IR, UV, (1)H & (13)C NMR). The complexes have been screened for anti-inflammatory activity.     

Pentamethylcyclopentadienyl ruthenium(III) vs hexamethylbenzene ruthenium(II) in sulfur-centered reactivity of their thioether-thiolate and allied complexes

The reactivity features of [Cp*Ru(III){eta(3)-tpdt)}] (7) and [(HMB)Ru(II)(eta(3)-tpdt)] (10) {Cp* = eta(5)-C(5)Me(5); HMB = eta(6)-C(6)Me(6); tpdt = 3-thiapentane-1,5-dithiolate, S(CH(2)CH(2)S(-))(2)} are presented, together with selected aspects of their (eta(3)-apdt) analogues 8 and 11 {apdt = 3-azapentane-1,5-dithiolate, HN(CH(2)CH(2)S(-))(2)}. This account will highlight the differences observed in their reactions with metal fragments of compounds of Ru and groups 10 and 11 in various coordination environments and with alkylating agents, including alpha,omega-dibromoalkanes. The mechanistic pathway of the alkylation of 7 will be discussed in some detail.     

4,4′-联苯二乙酰丙酮桥联双核镍(Ⅱ)配合物的合成及磁性研究

以4,4′-联苯二乙酰丙酮和二苯甲酰甲烷为原料合成了标题化合物,并用元素分析、电导率、红外光谱、电子光谱和电喷雾质谱对其进行了表征,确定了配合物的组成,研究了配合物在氮气气氛中的热分解行为。其变温磁化率(2~300 K)的测定结果表明,桥联双核Ni2+配合物为铁磁性自旋交换作用,Curie常数C=2.04 cm3.mol-1.K,Weiss常数θ=8.10 K。     

Aspirin analogues as dual cyclooxygenase-2/5-lipoxygenase inhibitors: synthesis, nitric oxide release, molecular modeling, and biological evaluation as anti-inflammatory agents

Analogues of aspirin were synthesized through an efficient one-step reaction in which the carboxyl group was replaced by an ethyl ester, and/or the acetoxy group was replaced by an N-substituted sulfonamide (SO(2)NHOR(2):R(2) =H, Me, CH(2)Ph) pharmacophore. These analogues were designed for evaluation as dual cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitors. In vitro COX-1/COX-2 isozyme inhibition studies identified compounds 11 (CO(2) H, SO(2)NHOH), 12 (CO(2)H, SO(2)NHOCH(2)Ph), and 16 (CO(2)Et, SO(2)NHOH) as highly potent and selective COX-2 inhibitors (IC(50) range: 0.07-0.7 μM), which exhibited appreciable in vivo anti-inflammatory activity (ED(50) range: 23.1-31.4 mg kg(-1)). Moreover, compounds 11 (IC(50) =0.2 μM) and 16 (IC(50) =0.3 μM), with a sulfohydroxamic acid (SO(2)NHOH) moiety showed potent 5-LOX inhibitory activity. Furthermore, the SO(2)NHOH moiety present in compounds 11 and 16 was found to be a good nitric oxide (NO) donor upon incubation in phosphate buffer at pH 7.4. Molecular docking studies in the active binding site of COX-2 and 5-LOX provided complementary theoretical support for the experimental biological structure-activity data acquired.     

Near infrared broadband emission of In0.35Ga0.65As quantum dots on high index GaAs surfaces

The morphology and optical properties of In(0.35)Ga(0.65)As/GaAs quantum dots (QDs) grown on (210), (311)A, (711)A, (731) and (100) substrates are investigated. QDs formed on (210) and (731) oriented substrates are grown by molecular beam epitaxy. Regular QDs are observed on (100), (311)A, and (711)A. Randomly distributed QDs and comet-shaped QDs form on (210) and (731) substrates, respectively. A high density of QDs on the order of 10(11) cm(-2) are obtained from (711)A. The optical measurement shows a spectrum linewidth (FWHM = 74.3 nm) of QDs on GaAs (210) three times wider than GaAs (100) substrate. Long exciton decay times, over 1 ns, are also measured by time-resolved photoluminescence technique for all samples. Our results demonstrate the potential for QDs on GaAs high index substrates for wideband applications.     

A novel organometallic ReI complex with favourable properties for bioimaging and applicability in solid-phase peptide synthesis

Organometallic complexes possess great potential for imaging applications in biology, due to their kinetic stability and often favourable intrinsic properties. In this work we present a new class of Re(I) -tricarbonyl complexes with a substituted bis(phenanthridinylmethyl)amine (bpm) ligand. The complex Re(CO)(3) (R-bpm) could be conveniently prepared by microwave synthesis from [Re(CO)(3)(H(2)O)(3) ]Br and a suitably substituted bis(phenanthridinylmethyl)amine (R-bpm). Complex 5, with R=CH(2)-CO(2)-CH(3) , was characterized by a single-crystal X-ray structure. Complex 6 (R=CH(2)-C(6)H(4)-CO(2)H) was used in solid-phase peptide synthesis (SPPS) to label the neurotensin(8-13) (NT) fragment N-terminally. The complexes show luminescence emission with large Stokes shifts (λ(ex) =350 nm, λ(em) =570 nm). Cellular uptake and intracellular localization studies in several cell lines demonstrate the utility of the new Re(CO)(3) (R-bpm) complexes for fluorescence imaging and reveal significant differences between the simple methyl ester 5 and the NT bioconjugate 7.     

Interaction of Some Non-Platinum Metal Anticancer Complexes With Nucleotides and DNA and The Two-Pole Complementary Principle (TPCP) Arising Therefrom

The binding modes of some non-platinum metal anticancer complexes, Cp(2)TiCl(2), Cp(2)ZrCl(2), (CH(3))(2)SnCl(2), (C(2)H(5))(2)SnCl(2), (C(2)H(5))(2)SnCl(2)(phen) (phen=Phenanthroline) and cis-Ru(II)Cl(2)(DMSO)(3) (DMSO) (cis-RDT) with nucleotides and DNA in aqueous solution at physiological pH values were investigated by various modern techniques. 5'-dGMP with Cp(2)TiCl(2) or cis-RDT forms chelate complexes in which both N(7) and phosphate of dGMP bind to the metal center. Whereas Cp(2)ZrCl(2) and all the diorganotin compounds can bind dGMP only via the phosphate group. The investigations of the interactions between Cp(2)TiCl(2) or (C(2)H(5))(2)SnCl(2) and DNA indicate that there are two types of binding sites on DNA for Cp(2)TiCl(2), i.e., the base nitrogen rings and the phosphate group, while (C(2)H(5))(2)SnCl(2) can bind to DNA only via the phosphate group. At last, by carefully comparing and analysing the binding modes-activity relationships of the above anticancer complexes and other non-platinum and platinum anticancer complexes, a hypothesis named "Two-Pole Complementary Principle" was put forward.     

Cooperative enhancement of two-photon absorption based on electron coupling in triphenylamine-branching chromophore

Two novel, triphenylamine derivatives N-(4-(4-(diphenylamino)styryl)phenyl)acetamide and N-(4-(4-(bis-(4-(4-(diphenyl-amino)styryl)phenyl)amino)styryl)phenyl)acetamide were synthesized. The two-photon absorption of N-(4-(4-(bis-(4-(4-(diphenyl-amino)styryl)phenyl)amino)styryl)phenyl) was 17-fold greater relative to N-(4-(4-(diphenylamino)styryl)phenyl)acetamide. Linear absorption spectra, steady-fluorescence and time-resolved fluorescence spectra revealed that electron coupling originating from π-electron delocalization is responsible for the strong cooperative enhancement of TPA within the compounds. This is confirmed by the Lippert-Mataga equation.     

Metallation of Isatin (2,3-Indolinedione). X-Ray Structure and Solution Behavior of Bis(Isatinato)Mercury(II)

The first X-ray structure of an isatin (2,3-indolinedione, isaH) metal complex, bis(isatinato)memury(II) (C(16)H(8)N(2)O(4)Hg) (1), was determined. (1) was obtained from the reaction of isaH with mercury(II) acetate in methanol. Analogously, treatment of sodium saccharinate and mercury(II) acetate in methanol yielded Hg(saccharinato)(2) (*)0.5CH(3)OH (3). (1) crystallizes in the monoclinic system, space group P2(1)/ a with a = 7.299(1) A, b = 8.192(1) A, c = 11.601(1) A , beta = 105.82(1) degrees , V = 667.4 A(3), Z = 2, D(calc) = 2.452 g cm(-3), MoKalpha radiation(lambda = 0.71073 A), mu = 115.5 cm(-1), F(000) = 460, 21(1) degrees C. The structure was refined on the basis of 2023 observed reflections to R= 0.044. The two deprotonated, non coplanar isa ligands are trans to each other in a head to tail orientation and bound to the Hg through the nitrogen in a linear N-Hg-N arrangement. The Hg atom is at the center of symmetry of the complex and displaced by 0.62 A from the two planes of the isa ligands (tau Hg-N1-C2-O2= -16 degrees ). The Hg-N bond length is 2.015 A. Nopi-aryl-memury(ll)-pi-aryl stacking interaction was observed either in the solid state or in the solution state. The IR, electronic, and (1)H and (13)CNMR spectral data of (1) and (3) suggest binding of the memury to the heterocyclic nitrogen, in agreement with the crystal structure determination of (1).     

Behaviors of plutonium and neptunium in nitric acid solutions containing hydrazine and technetium ions

The valence behaviors of plutonium and neptunium in the interaction of Pu(IV) and Np(V) with hydrazine and tetravalent uranium in technetium(VII)-containing aqueous nitric acid are reported. At [HNO₃] = 1 mol/l and Pu(IV) and Tc(VII) concentrations of ～0.1 and 0.01–0.2 mol/l, respectively, Pu(IV) is reduced to Pu(III) and is then entirely reoxidized to Pu(IV). Neptunium(V) in 1–3 M HNO₃ undergoes reduction to Np(IV) and then turns back into Np(V). The resulting solution usually contains a mixture of Np(IV) and Np(V). The reduction of Pu(IV) to Pu(III) and the reduction of Np(V) to Np(IV) are accompanied by hydrazine decomposition and by the reduction of most of the Tc(VII) to its lower valence forms. The conversions of Pu(III) into Pu(IV) and of Np(IV) into Np(V) are accompanied by the oxidation of these forms of technetium to Tc(VII). The introduction of diethylenetriaminepentaacetic acid into the reaction system makes Pu(III) more stable against reoxidation into Pu(IV) by reducing the hydrazine decomposition rate, enhances the conversion of Np(V) into Np(IV), and hampers Np(IV) oxidation to Np(V).     

Facile fabrication of NH(4)CoPO(4)·H(2)O nano/microstructures and their primarily application as electrochemical supercapacitor

Various NH(4)CoPO(4)·H(2)O nano/microstructures (oblong plate, microplate, microflower, hierarchical architectures) have been synthesized through a facile chemical precipitation method without surfactants and templates. More importantly, the supercapacitive performances of NH(4)CoPO(4)·H(2)O nano/microstructures were firstly studied using cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy methods in 3.0 M KOH solution. These results indicated that NH(4)CoPO(4)·H(2)O hierarchical architectures electrodes exhibit effective supercapacitive characteristics in aqueous KOH electrolyte. The specific capacitance of NH(4)CoPO(4)·H(2)O electrode is up to 369.4 F g(-1) at a current density of 0.625 A g(-1) and the material has a long cycle life which can maintain 99.7% of initial specific capacitance after 400 cycles.     

Redox Chemistry and [Au(CN)(2)] in the Formation of Gold Metabolites

The role of hypochlorite ion, which can be generated by the enzyme myleoperoxidase, in the biochemistry of gold(I) anti-arthritic drugs was investigated. Sodium hypochlorite (OCl(-)) directly and rapidly oxidizes AuSTm, Au(CN)(2) (-), AuSTg (gold thioglucose) and auranofin (Et(3)PAuSATg). The resulting gold(III) species were detected by an Ion Chromotography Ion-Pairing technique that was developed to distinguish gold(I) and gold(III). Formation of Au(III) was also demonstrated spectrophotometrically after the conversion to AuCl(4) (-). The reactions of AuSTm, AuSTg, and auranofin are complex and gold(III) appears only after the initial oxidation of the thiolate (and phosphine) ligands.The enzymatic reaction, using MPO with H(2)O(2) and Cl(-) as substrates, leads to slow oxidation of Au(CN)(2) (-), AuSTm or AuSTg. The extent and rate of reaction depend on the concentrations of MPO, H(2)O(2), and Au(I). The continued presence of Au(I) during the initial stages of reaction (oxidation of the thiolates in AuSTm and AuSTg) and the conversion to Au(III) in the latter stages of the reaction were demonstrated. Au(CN)(2) (-), a gold metabolite, binds tightly to serum albumin. Unlike other gold(I) complexes, aurocyanide reacts almost negligibly at Cys-34 via ligand exchange. Instead, there is a strong association (K(1) = 5.5 x 10(4) and K(2) = 7.0 x 10(3); n(1) = 0.8 and n(2) = 3) of intact Au(CN)(2) (-). The full extent of binding is revealed only by equilibrium methods such as NMR or ultrafiltration; the bound gold dissociates extensively on conventional gel-exclusion columns and partially on Penefesky spun columns.The immunological and pharmacological significance of these results are discussed.     

C₇₄ endohedral metallofullerenes violating the isolated pentagon rule: a density functional theory study

Precise studies on M(2)@C(74) (M = Sc, La) series by means of DFT methods have disclosed that certain non-IPR isomers are more stable than the IPR structure. M(2)@C(2)(13295)-C(74) and M(2)@C(2)(13333)-C(74), both of which have two pentagon adjacencies (PA), present excellent thermodynamic stability with very small energy differences. Statistical mechanics calculations on the M(2)@C(74) series reveal that M(2)@C(2)(13295)-C(74) and M(2)@C(2)(13333)-C(74) are quite favoured by entropy effects below 3000 K. Sc(2)@C(74) and La(2)@C(74) series are found to have similar electronic transfer but different electronic structures due to the distinct properties of scandium and lanthanum elements according to Natural Bond Orbital (NBO) analysis in conjunction with orbital interaction diagrams. Investigations of bonding energies reflect quite different influences of the two types of metal atoms to C(74) metallo-fullerenes. Further examinations on C(74) metallo-fullerenes uncover significant stabilization effects of metal atoms acting on PA fragments. Geometrical structures of certain non-IPR cages (from C(72) to C(76)), which exhibit splendid stabilities when encapsulating metallo-clusters, are found to be related by Stone-Wales transformation and C(2) addition. Furthermore, IR spectra and (13)C NMR spectra of M(2)@C(2)(13295)-C(74) and M(2)@C(2)(13333)-C(74) have been simulated to assist further experimental characterization.     

Effect of Tb(III) on the properties of P(NIPAM-co-St) copolymer microspheres

Based on the synthesis of copolymer microspheres of N-isopropylacrylamide (NIPAM) and styrene (st) (P(NIPAM-co-St)), the interaction of Tb(III) and P(NIPAM-co-St) was investigated. It was found that when Tb(III) interacts with P(NIPAM-co-St) Tb(III) mainly bonds to O of the carbonyl group of P(NIPAM-co-St), forming the novel P(NIPAM-co-St)-Tb(III) complex. LCST, the zeta potential and the emission fluorescence intensity of P(NIPAM-co-St)-Tb(III) complex are different from P(NIPAM-co-St). Especially, after forming the complex, the intensities of the emission fluorescence peaks of Tb(III) at 487, 544 and 585 nm are enhanced 34, 35 and 17 times, respectively, comparing with that of the corresponding peaks of TbCl₃. Therefore, the P(NIPAM-co-St)-Tb(III) complex could transform the harmful ultraviolet radiation to harmless visible light. It is hoped that the results will provide a reference point for new applications of complexes of polymers and rare-earth elements, such as the P(NIPAM-co-St)-Tb(III) complex, in biomedicine and fluorescence systems.     

Bond strengths of toluenes, anilines, and phenols: to hammett or not

The Hammett equation correlates the effects of Y on many different chemical properties of YC(6)H(4)ZX families of compounds. One of the most surprising is that the Z-X bond dissociation enthalpy (BDE), a homolytic property, can be correlated for some 4-YC(6)H(4)ZX families with electrophilic substituent constants, sigma(p)(+)(Y), which were largely derived from the rates of the heterolytic S(N)1 solvolyses of para-substituted cumyl chlorides. Although there is no Hammett correlation of the C-X BDEs in 4-YC(6)H(4)CH(2)X (X = H, halide, OPh) families, there are good correlations of N-X BDEs with sigma(p)(+)(Y) in 4-YC(6)H(4)NHX (X = H, CH(3), OH, F) and excellent correlations of O-X BDEs with sigma(p)(+)(Y) in 4-YC(6)H(4)OX (X = H, CH(3), CH(2)Ph) families. The reasons for this varied behavior are discussed.     

2, 2'-(Phenylazanediyl) diacetic acid modified Fe3O4@PEI for selective removal of cadmium ions from blood

A water-dispersible and supermagnetic nanocomposite (PAD-PEG-Fe(3)O(4)@PEI) has been successfully synthesized using polyethylenimine (PEI, Mol MW = 10000) coated supermagnetic Fe(3)O(4)-NH(2) which was modified with 2, 2'-(phenylazanediyl) diacetic acid (PAD) through the bridge of poly(ethylene glycol) (PEG, Mol MW = 2000). The average particle size of PAD-PEG-Fe(3)O(4)@PEI was determined by TEM, and was about 50 nm. From magnetic hysteresis cycles for PAD-PEG-Fe(3)O(4)@PEI at room temperature, the saturation magnetization (Ms) was shown to be 58.14 emu g(-1). Inductively coupled plasma spectrometry (ICP) analysis showed that the designed magnetic nanocomposite can remove 98% and 80% of Cd(2+) from water and blood, respectively.     

Interaction of Pd(II) and Pt(II) Amino Acid Complexes With Dinucleotides

The interaction of the dinucleotides d(ApG) and d(ApA) with [Pd(aa)Cl(2)], where aa = L- or D-histidine or the methyl ester of L-histidine, and with [Pt(Met)Cl(2)], where Met = L-methionine was studied by (1)H and (13)C NMR and CD measurements. In the case of the L-histidine and L-histidineOMe, the reaction with d(ApG) appeared to give the bifunctional adducts Pd(L-Histidine)N1(1)N7(2) and Pd(L-HisOMe)N1(1)N7(2), but the behavior with D-histidine suggested the formation of the monofunctional adduct Pd(D-His)N7(2). The reaction of L-histidine with d(ApA) seemed to form the bimetallic adduct (L-His)PdN7(1)N7(2)Pd(L-His). The Pt(II)-L-methionine complex in both reactions with d(ApG) and d(ApA) seemed to yield mainly adducts Pt(L-Met)N7(1)N7(2) but the existence of adducts Pt(L-Met)N1(1)N7(2) cannot be ruled out.     

Reactions of organic disulfides and gold(i) complexes

Gold-thiolate/disulfide exchange reactions of (p-SC(6)H(4)Cl)(2) with Ph(3)PAu(SC(6)H(4)CH(3)), dppm(AuSC(6)H(4)CH(3))(2), and dppe(AuSC(6)H(4)CH(3)) (2) were investigated. The rate of reactivity of the gold-thiolate complexes with (p-SC(6)H(4)Cl)(2) is: dppm(AuSC(6)H(4)CH(3))(2)> dppe(AuSC(6)H(4)CH(3))(2)>Ph(2)PAu (SC(6)H(4)CH(3)). This order correlates with conductivity measurements and two ionic mechanisms have been evaluated. (1)H NMR experiments demonstrate that in the reaction of dppm(AuSC(6)H(4)CH(3))(2) with (p-SC(6)H(4)Cl)(2), the mixed disulfide, ClC(6)H(4)SSC(6)H(4)CH(3), forms first, followed by the formation of (p-SC(6)H(4)CH(3))(2). The rate law is first order in (pp-SC(6)H (4)Cl)(2) and partial order in dppm(AuSC(6)H(4)CH(3))(2). Results from electrochemical and chemical reactivity studies suggest that free thiolate is not involved in the gold-thiolate/disulfide exchange reaction. A more likely source of ions is the dissociation of a proton from the methylene backbone of the dppm ligand which has been shown to exchange with D(2)O. The implications of this are discussed in terms of a possible mechanism for the gold-thiolate/disulfide exchange reaction.