肉苁蓉多糖锌的制备、表征及抗氧化活性

采用超声酶法辅助提取肉苁蓉粗多糖,并用季铵盐沉淀法对肉苁蓉粗多糖进行精制,获得肉苁蓉精制多糖(UCEP1);以UCEP1和硫酸锌为原料,制备了肉苁蓉多糖锌配合物(UCEP1-Zn),对其结构进行了表征,并研究其抗氧化活性.结果表明,肉苁蓉粗多糖收率及含量分别为22.31%和48.50%,UCEP1中多糖含量为70.13%;UCEP1-Zn中-OH和-COO~-和Zn~(2+)发生了配位,其中锌含量为7.57%,且多糖链构象及多糖分子表面形貌发生变化;UCEP1-Zn的抗氧化能力显著高于UCEP1,且对ABTS~+自由基清除活性最好.该研究可为肉苁蓉多糖、新型锌营养素补充剂以及锌功能配合物的研究和利用提供参考.     

Synthesis, characterization and antioxidant activity of naringenin Schiff base and its Cu(II), Ni(II), Zn(II) complexes

A new ligand, naringenin-2-hydroxy benzoyl hydrazone (H(5)L), was prepared by condensation of naringenin with 2-hydroxy benzoyl hydrazine. Its Cu(II), Ni(II), Zn(II) complexes have also been synthesized and characterized on the basis of (1)H-NMR, IR, UV-Vis spectra, elemental analyses, molar conductivity and thermal analyses. The general formula of these complexes was M(H(3)L) [M=Cu(II), Ni(II) and Zn(II)]. In addition, the antioxidant activities (superoxide and hydroxyl radical) of the free ligand and its complexes were determined in vitro. These compounds were found to possess potent antioxidant activity and be better than standard antioxidants like vitamin C and mannitol. In particular, the Cu(II) complex displayed excellent activity on the superoxide radical.     

Synthesis,structure and bioactivity of Ni2+ and Cu2+ acylhydrazone complexes

Two acylhydrazone complexes, bis{6‐methyl‐N′‐[1‐(pyrazin‐2‐yl‐κN¹)ethylidene]nicotinohydrazidato‐κ²N′,O}nickel(II), [Ni(C₁₃H₁₂N₅O)₂], (I), and di‐μ‐azido‐κ⁴N¹:N¹‐bis({6‐methyl‐N′‐[1‐(pyrazin‐2‐yl‐κN¹)ethylidene]nicotinohydrazidato‐κ²N′,O}nickel(II)), [Cu₂(C₁₃H₁₂N₅O)₂(N₃)₂], (II), derived from 6‐methyl‐N′‐[1‐(pyrazin‐2‐yl)ethylidene]nicotinohydrazide (HL) and azide salts, have been synthesized. HL acts as an N,N′,O‐tridentate ligand in both complexes. Complex (I) crystallizes in the orthorhombic space group Pbcn and has a mononuclear structure, the azide co‐ligand is not involved in crystallization and the Ni²⁺ centre lies in a distorted {N₄O₂} octahedral coordination environment. Complex (II) crystallizes in the triclinic space group P and is a centrosymmetric binuclear complex with a crystallographically independent Cu²⁺ centre coordinating to three donor atoms from the deprotonated L^? ligand and to two N atoms belonging to two bridging azide anions. The two‐ and one‐dimensional supramolecular structures are constructed by hydrogen‐bonding interactions in (I) and (II), respectively. The in vitro urease inhibitory evaluation revealed that complex (II) showed a better inhibitory activity, with the IC₅₀ value being 1.32±0.4 µM. Both complexes can effectively bind to bovine serum albumin (BSA) by 1:1 binding, which was assessed via tryptophan emission–quenching measurements. The bioactivities of the two complexes towards jack bean urease were also studied by molecular docking. The effects of the metal ions and the coordination environments in the two complexes on in vitro urease inhibitory activity are preliminarily discussed.     

CO2 Fixation by Cu2+ and Zn2+ complexes of a terpyridinophane aza receptor. Crystal structures of Cu2+ complexes, pH-metric, spectroscopic, and electrochemical studies

The synthesis of the terpyridinophane-type polyamine 2,6,9,12,16-pentaaza[17]-(5,5' ')-cyclo-(2,2':6',2' ')-terpyridinophane heptahydrobromide tetrahydrate (L.7HBr.4H2O) is described. L presents six protonation constants with values in the range 9.21-3.27 logarithmic units. L interacts with Cu2+ and Zn2+ forming in both cases, neutral, protonated, and hydroxylated mono- and binuclear complexes whose constants have been calculated by potentiometry in 0.15 M NaClO4 at 298.1 K. The crystal structures of the compounds [Cu(HL-carb)(H2O)](ClO4)3.2H2O (1) and [Cu2(H2L)(CO3)]2(ClO4)8.9H2O (2) have been solved by X-ray diffraction. In 1, the metal center presents square pyramidal geometry. The base of the pyramid is formed by the three nitrogen atoms of pyridine and one oxygen atom of a CO2 group which is forming a carbamate bond with the central nitrogen atom of the polyamine chain. The axial position is occupied by a water molecule. In 2, one Cu2+ is bound by the three pyridine nitrogens and the other one by the three central nitrogen atoms of the polyamine chain. The square planar coordination geometry is completed by a carbonate group taken up from the atmosphere that behaves as a bridging mu,mu'-ligand between the two centers. The pH-metric titrations on the ternary Cu2+-L-carbonate and Zn2+-L-carbonate systems show the extensive formation of adduct species which above pH 6 are formed quantitatively in solution. The stoichiometries of the main species formed in solution at pH = 6.8 agree with those found in the crystalline compounds. CO2 uptake by the Zn2+ and Cu2+ 1:1 complexes in aqueous solution has also been followed by recording the variations in the band at ca. 300 nm. The formation of the Zn2+ carbamate moiety has been evidenced by 13C NMR and ESI spectroscopy.     

Synthesis,characterization, and antioxidant activities of three Cu(II) complexes with Schiff-base ligands

Cu(II) complexes of three bis(pyrrol-2-yl-methyleneamine) ligands were synthesized and characterized by elemental analyses, mass spectra, and IR spectra. X-ray diffraction analysis shows that [CuL³]₂ is a dinuclear complex with an extremely distorted square-planar geometry. Furthermore, the antioxidant activities of the compounds have been investigated. The electrochemical properties of the Cu(II) complexes have also been studied by cyclic voltammetry. The Cu(II) complexes show similar superoxide dismutase (SOD) activity compared with that of the native Cu, Zn-SOD.     

Synthesis, characterization and antioxidant activity copper-quercetin complex

Quercetin (3,3',4',5,7-pentahydroxyflavone) one of the most abundant dietary flavonoids, has been investigated in the presence of Cu(II) in methanol. The spectroscopic studies (UV-vis, (1)H NMR and IR) were useful to assess the relevant interaction of Quercetin with Cu(II) ions, the chelation sites and dependence of the complex structure from the metal/ligand ratio. A 1:2 (L:M) complex was indicated by Job's method of continuous variation, which was applied to ascertain the stoichiometric composition of the complex. The antioxidant activities of the compounds were evaluated by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method. The complexed flavonoid was much more effective free radical scavengers than the free flavonoids.     

Synthesis,characterization and antioxidant,antibacterial activity Zn2+, Cu2+, Ni2+ and Co2+, complexes of ligand [2-(thiophen-2-yl)-1-(thiophen-2-ylmethyl)-1H-benzo[d]imidazole]

New metal complexes of (Zn(II), Co(II), Ni(II) and Cu(II)) based on the ligand 2-(thiophen-2-yl)-1-(thiophen-2-ylmethyl)-1H-benzo[d]imidazole] were synthesized, whose structures were determined with the different spectroscopic techniques ¹H NMR,¹³C NMR, FT-IR, UV–Visible and by mass spectrometry. The thermal analysis was performed by TG-DTA. The antioxidant activity of the ligand and its complexes was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) method, in comparison with the synthetic antioxidant, ascorbic acid. The results obtained showed that the antioxidant activity of the ligand and its complexes is moderate and that the copper complex has a high activity that exceeds that of ascorbic acid. Antimicrobial activity of the ligand and its metal complexes was studied against two Gram-positive bacteria: Bacillus subtilis ILP1428B, Staphylococcus aureus CIP543154 and two Gram-negative bacteria: Pseudomonas aeruginosa ATCC27653, Escherichia coli CIP5412 (American Type Culture Collection)the activity data show that the metal complexes are more potent than the free ligand.     

Synthesis and structure of chloronitroacetamide complexes with Cu2+ and Ni2+ ions

Conclusions Stable complexes of chloronitroacetamide with Cu²⁺ and Ni²⁺ ions were synthesized. The molecular structure of bis(chloronitroacetamidato) tetramminecopper(II) was determined by x-ray diffraction structural analysis.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 214–216, January, 1987.     

Synthesis and study of properties of the polyhexamethyleneguanidine complexes with the ions Cu2+, Zn2+, and Ni2+

The reaction products of polyhexamethyleneguanidine hydrochloride with the Cu²⁺, Zn²⁺, and Ni²⁺ ions, which are the polyligand coordination compounds formed by polyguanidine and hydroxyl ligands, were studied using IR, UV, and ESR spectroscopy. The influence of the nature of the chelating agent on the structure of the complexes formed was revealed. Antibacterial properties of the synthesized complexes were assessed.     

Novel 2-formylpyridine 4-allyl-S-methylisothiosemicarbazone and Zn(II), Cu(II), Ni(II) and Co(III) complexes: Synthesis,characterization, crystal structure,antioxidant, antimicrobial and antiproliferative activity

New zinc (II), copper (II), nickel (II) and cobalt (III) complexes, [Zn (HL)₂]I₂ (1) , [Cu (HL)Cl₂] (2) , [Cu (HL)Br₂] (3) , [Cu (HL)(H₂O)₂](ClO₄)₂ (4) , [Ni (HL)₂]I₂·H₂O (5) , [Co(L)₂]Cl (6) , [Co(L)₂]NO₃ (7) , [Co(L)₂]I·[Co(L)₂](I₃) (8) were obtained with 2-formylpyridine 4-allyl-S-methylisothiosemicarbazone ( HL ). The isothiosemicarbazone ligand was characterized by NMR (¹H and ¹³C), IR spectroscopy and X-ray diffraction. All the complexes were characterized by elemental analysis, IR, UV–Vis, ESI-MS spectroscopy, molar conductivity, magnetic susceptibility measurements. X-ray diffraction analysis on the monocrystal and powder elucidated the structure of the complexes 1 , 5 , 7 and 8 . The ligand and the complexes were tested for their antioxidant and antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Candida albicans. Also, the antiproliferative properties of these compounds on human leukemia HL-60, human cervical epithelial HeLa, human epithelial pancreatic adenocarcinoma BxPC-3, human muscle rhabdomyosarcoma spindle, large multinucleated RD cells and normal MDCK cells have been investigated. The nickel complex 5 and cobalt complexes 6 , 7 showed promising antiproliferative activity and low toxicity.     

Synthesis,characterization, and catalytic activity of heterometallic ion-pair Ni/Mn and Ni/Zn complexes

Two new heterometallic compounds, [Ni(bpy)₃][Mn(NCO)₄]·H₂O (1) and [Ni(phen)₃]₂[Zn(NCO)₄]₂·4DMSO·H₂O (2) [bpy?=?2,2′-bipyridine and phen?=?1,10-phenanthroline], have been synthesized and characterized. The structures of 1 and 2 were solved by single-crystal X-ray diffraction analysis. The cationic moieties of [Ni(bpy)₃]²⁺ in 1 and [Ni(phen)₃]²⁺ in 2 show octahedral environments around Ni(II), whereas the anionic groups of [Mn(NCO)₄]^2? in 1 and [Zn(NCO)₄]^2? in 2 exhibit tetrahedral geometry around the Mn(II) and Zn(II), respectively. Both compounds are catalysts in the H/D exchange of salicylaldehyde in DMSO-d₆ which takes place under mild conditions and short reaction time.     

Ionic metallo‐Schiff base polymers of VO2+, Zn2+ and Cu2+: Synthesis,characterization and solid‐state conductivity

The viologen‐type dialdehyde of [N,N′‐bis(methylsalicylaldehyde)‐4,4′‐bipyridinium] dichloride (DA) was synthesized by reacting 5‐chloromethylsalicylaldehyde and 4,4′‐bipyridine. Then a new polymeric Schiff base ligand (PSBL) was synthesized by the condensation reaction of ethylenediamine and DA in methanol under reflux conditions. Afterwards, new ionic metallo‐Schiff base polymers (IMSPs) were synthesized by reacting PSBL with VO(acac)₂, ZnCl₂ and CuCl₂ via coordination chelation. DA, PSBL and IMSPs were characterized using various analytical methods and spectral techniques. The solid‐state electrical conductivities of PSBL and IMSPs were studied. The electrical conductivity of these polymers at 300 K ranged from 1.30 × 10^?5 to 4.52 × 10^?10 Ω^?1 m^?1, which means they are potential organic and metallo‐organic semiconductors.     

Synthesis,characterization, and antioxidant activity of heterocyclic Schiff bases

Schiff base derivatives have gained great importance due to revealing a great number of biological properties. Schiff bases were synthesized by treatment of 4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one ( 1 ) with various aldehydes in methanol at reflux. In addition, diamine was reacted with an aldehyde to yield the corresponding Schiff bases. The structures of synthesized Schiff bases were elucidated by spectroscopic methods such as microanalysis, ¹H-NMR, ¹³C-NMR, and FTIR. Antioxidant activities of synthesized Schiff bases were carried out using different antioxidant assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH^•) scavenging, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging, and reducing power activity. (E)-4-((1H-indol-3-yl)methyleneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one ( 3 ), (E)-1,5-dimethyl-4-((2-methyl-1H-indol-3-yl)methyleneamino)-2-phenyl-1H-pyrazol-3(2H)-one ( 5 ), (E)-1,5-dimethyl-2-phenyl-4-(thiophen-2-ylmethyleneamino)-1H-pyrazol-3(2H)-one ( 7 ), (E)-1,5-dimethyl-2-phenyl-4-(quinolin-2-ylmethyleneamino)-1H-pyrazol-3(2H)-one ( 9 ), (1S,2S,N1,N2)-N1,N2-bis((1H-indol-3-yl)methylene)cyclohexane-1,2-diamine ( 11 ), and (1S,2S,N1,N2)-N1,N2-bis((2-methyl-1H-indol-3-yl)methylene)cyclohexane-1,2-diamine ( 12 ) were synthesized in high yields. Compound 5 displayed a good ABTS^•+ activity. Compound 3 revealed the outstanding activity in all assays. Compound 7 has the best-reducing power ability in comparison to other synthesized compounds. Although compounds 5, 11, 12 are new, compounds 3, 7, 9 are known. Due to revealing a good antioxidant activity, the synthesized compounds ( 3, 5, 7 ) have the potential to be used as synthetic antioxidant agents.     

Synthesis, characterization, and antioxidant activity of some ebselen analogues

Simple synthetic routes for several analogues of the anti-inflammatory organoselenium drug, ebselen, are described. The compounds are characterized by (1)H, (13)C, and (77)Se NMR spectroscopy and mass spectral techniques and, in some cases, by single-crystal X-ray diffraction studies. The glutathione peroxidase (GPx)-like antioxidant activity has been studied by using H(2)O(2), tBuOOH, and Cum-OOH as substrates, and thiophenol (PhSH, 4-Me-C(6)H(4)SH) and glutathione (GSH) as cosubstrates. Density functional theory (DFT) calculations have been performed on these systems to understand the effects of various substituents on the (77)Se NMR chemical shifts; these results have been compared with the experimental data. The experimental and theoretical results suggest that the presence of a phenyl substituent on the nitrogen atom is important for the antioxidant activity of ebselen. While ebselen and its analogues are poor catalysts in aromatic thiol assays, these compounds exhibit high GPx activity when GSH is used as the cosubstrate. The poor catalytic activity of ebselen analogues in the presence of aromatic thiols such as PhSH and 4-Me-C(6)H(4)SH can be ascribed to the undesired thiol exchange reaction that takes place at the selenium center due to SeO nonbonding interactions. To understand the effects of different peroxides on the catalytic activities, we have determined the initial rates at various concentrations of GSH and peroxides. These data suggest that the nature of peroxide has little effect on the catalytic efficiencies, although the initial reaction rates observed with hydrogen peroxide were found to be higher than that with tBuOOH and Cum-OOH. In contrast to the effect of peroxides, the nature of thiols appears to have a dramatic effect on the catalytic activity of ebselen and its related derivatives.     

2-氨甲基吡啶缩5-溴水杨醛席夫碱配合物的合成、表征与抗氧化作用

以乙醇为溶剂合成了2-氨甲基吡啶缩5-溴水杨醛席夫碱(HL,C13H11N2OBr)的Zn(Ⅱ)、Cd(Ⅱ)、Co(Ⅲ)配合物[ZnL2]、[CdL2]和[CoL2]NO3·3H2O,利用红外光谱、紫外光谱、热重分析、元素分析及摩尔电导等方法对配合物的组成和结构进行了表征,探讨了配合物的抗氧化活性.     

Synthesis of liquid crystal ferrocene derivatives and their complexes with Cu2+

A series of liquid crystal ferrocene-containing Schiff bases of general formula C₅H₅FeC₅H₄-C₆H₄-N=CN-(X)C₆H₃-O(O)-C₆H₄-OC_nH_2n+1 (X=H, OH, n=3–12) was obtained, together with several analogs, 1,1-bis-substituted at the ferrocene fragment, having a thermotropic nematic mesophases. Derivatives with X=OH were used to obtain Cu²⁺ chelate complexes, of which the compounds with n=10 and n=12 displayed nematic liquid crystalline properties.Physicotechnical Institute, Kazan Scientific Center, Russian Academy of Sciences, 420083 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 402–407, February, 1992.     

Heteroscorpionate-based Co2+, Zn2+, and Cu2+ complexes: coordination behavior, aerobic oxidation, and hydrogen sulfide detection

The coordination behavior and reactivity of the phenol-substituted bis(pyrazolyl)methane ligands, (3,5-(t)Bu(2)-2-phenol)bis(3,5-Me(2)-pyrazol-1-yl)methane (L1-H) and 2-phenol-bis(3,5-Me(2)-pyrazol-1-yl)methane (L2-H) have been investigated in the metal complexes (L1-H)CoCl(2) (1), (L1-H)ZnCl(2) (2), (L3)CuCl(2) (3), (L2)(2)Co(2)Cl(2) (4) (L2-H)ZnCl(2) (5), and (L2-H)CuCl(2)·H(2)O (6). The mononuclear tetrahedral cobalt complex 1 was isolated and fully characterized by X-ray single crystal diffraction and (1)H NMR spectroscopy and relaxometry. The neutral L1-H is κ(2)-coordinated to the metal center whereas the not coordinated hydroxy-phenyl group is involved in extended intermolecular hydrogen bonds. Aerobic oxidation of L1-H was observed in the reaction of this ligand with CuCl(2) to yield the para-quinone derivative L3 (L3 = 2-(t)Bu-6-(bis(3,5-Me(2)-pyrazol-1-yl)methyl)cyclohexa-2,5-diene-1,4-dione). Upon oxidation L3 resulted κ(2)-coordinated to the tetrahedral Cu(II) metal center, affording 3. The reaction of L2-H with CoCl(2)·6H(2)O produced the elimination of 1 equiv of hydrochloric acid and the formation of the binuclear complex 4 in which one cobalt is in an octahedral environment featuring two κ(3)-coordinated deprotonated ligands whereas the second cobalt center is detected in tetrahedral coordination geometry, bound to the octahedral cobalt via two phenoxo bridging moieties. Interestingly L2-H, (3-(t)Bu-2-phenol)bis(3,5-Me(2)-pyrazol-1-yl)methane (L4-H), or (5-(t)Bu-2-phenol)bis(3,5-Me(2)-pyrazol-1-yl)methane (L5-H) were not oxidized in the reaction with CuCl(2). The reaction of the ligand L2-H with ZnCl(2) and CuCl(2)·2H(2)O yielded the κ(2)-coordinated tetrahedral complex 5 and the square planar complex 6, respectively. The application of the cobalt complex 1 as molecular dosimeter for H(2)S was explored and compared to that of the zinc analogue 2. Density functional theory (DFT) calculations and NMR experiments to assess the possible mechanisms of H(2)S detection by both 1 and 2 are also described.