两种含硫Schiff碱及其配合物的合成与光谱性质

合成了2-氨基噻唑缩5-溴水杨醛(HBrsatz)和2-乙酰噻吩缩4-羟基苯甲酰腙(Hetphz)两种含硫Schiff碱及其配合物[Cu(Brsatz)2](Ⅰ)和[Cd(H2O)(Hetphz)(phen)](NO3)2(Ⅱ),通过元素分析、红外光谱和紫外光谱对它们的结构进行了表征,并研究了它们在DMF溶液中的发光性质,结果表明HBrsatz和Hetphz及配合物Ⅱ具有较强的荧光发射.     

Antifungal active tetraaza macrocyclic transition metal complexes: Designing, template synthesis, and spectral characterization

Eight novel macrocyclic complexes as candidates of antifungal agent were designed and synthesized by incorporating an N₄ donor site via the template condensation of 4,4′-diaminodiphenylmethane, formaldehyde. p-anisidine, and metal salts. The structural features were determined on the basis of their elemental analyses, magnetic susceptibility, molar conductance, FAB Mass, UV-Vis, and IR spectral data. Electronic absorption spectral data of the complexes suggest a square-planar geometry around the central metal ion except the VO(IV) complex, which shows square-pyramidal geometry. The stoichiometry of the complexes had been found to be 1: 1 (metal: ligand). Electrolytic nature of the complexes is assessed from their high conductance data. Monomeric nature of the complexes is confirmed from magnetic susceptibility values. The X-band ESR spectra of the Cu(II) and VO(IV) complexes in DMSO at 300 and 77 K were recorded, and their salient features are reported. The antifungal activity of the macrocyclic metal complexes were screened in vitro against Aspergillus niger, Aspergillus fluvus, Trichoderma harizanum, Trichoderma viridae, and Rhizoctonia solani. The data showed that they possessed antifungal activity. The article is published in the original.     

Synthesis and structural characterization of a fully conjugated macrocyclic tetraaza(14)-membered Schiff base and its bivalent metal complexes

A novel 14-membered macrocyclic Schiff base derived from 3-cinnamalideneacetoacetanilide and o-phenylenediamine acts as a tetradentate and strongly conjugated ligand to form a cationic solid complex with CuCl₂/NiCl₂/CoCl₂/ZnCl₂. The ligand and the complexes were characterized by the usual spectral and analytical techniques. The main i.r. band of the macrocyclic Schiff base was compared to that of its metal complexes. The C=N bands are shifted to the lower wave number. The cyclic voltammogram of the copper complex shows that the macrocyclic ligand is able to stabilize the copper(III) oxidation state. The e.s.r. spectra of the copper complex in DMSO solution at room temperature and liquid N₂ temperature were recorded and their salient features thoroughly discussed. The antimicrobial screening tests were also recorded and gave good results in the presence of metal ions in the ligand system.     

Synthesis,characterization and antibacterial properties of Schiff bases and Schiff base metal complexes derived from 2,3-diamino- pyridine

New copper(II), zinc(II) and nickel(II) Schiff base complexes derived from 2,3-diaminopyridine (DAPY) and selected aldehydes, namely salicylaldehyde (SalH), 4-hydroxybenzaldehyde (4-OHBenz) and 4-nitrobenzaldehyde (4-NO₂Benz), and one mixed Schiff base, DAPY-{4-OHBenz}{SalH} were prepared and characterized by a combination of elemental analyses, i.r. and n.m.r. spectra, and magnetic susceptibility measurements. The Schiff bases and some of the metal complexes display antibacterial properties.     

Synthesis,spectral characterization and biological studies of transition metal(II) complexes with triazole Schiff bases

New metal based triazoles (1–12) have been synthesized by the interaction of novel Schiff base ligands (L¹–L³) with the Co(II), Ni(II), Cu(II) and Zn(II) metal ions. The Schiff base ligands and their all metal(II) complexes have been thoroughly characterized using various physical, analytical and spectroscopic techniques. In vitro bacterial and fungal inhibition studies were carried out to examine the antibacterial and antifungal profile of the Schiff bases in comparison to their metal(II) complexes against two Gram‐positive, four Gram‐negative and six fungal strains. The bioactivity data showed the metal(II) complexes to have more potent antibacterial and antifungal activity than their uncomplexed parent Schiff bases against one or more bacterial and fungal species. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis, potentiometric and antimicrobial studies on metal complexes of isoxazole Schiff bases

The metal complexes of Cu(II), Ni(II) and Co(II) with Schiff bases of 3-(2-hydroxy-3-ethoxybenzylideneamino)-5-methyl isoxazole [HEBMI] and 3-(2-hydroxy-5-nitrobenzylidene amino)-5-methyl isoxazole [HNBMI] which were obtained by the condensation of 3-amino-5-methyl isoxazole with substituted salicylaldehydes have been synthesized. Schiff bases and their complexes have been characterized on the basis of elemental analysis, magnetic moments, molar conductivity, thermal analysis and spectral (IR, UV, NMR and Mass) studies. The spectral data show that these ligands act in a monovalent bidentate fashion, co-ordinating through phenolic oxygen and azomethine nitrogen atoms. Chelates of Co(II), Ni(II) appear to be octahedral and Cu(II) appears to be distorted octahedral. To investigate the relationship between formation constants of binary complexes and antimicrobial activity, the dissociation constants of Schiff bases and stability constants of their binary metal complexes have been determined potentiometrically in aqueous solution at 30+/-1 degrees C and at 0.1 M KNO3 ionic strength and discussed. Antimicrobial activities of the Schiff bases and their complexes were screened. The structure-activity correlation in Schiff bases and their metal(II) complexes are discussed, based on the effect of their stability constants. It is observed that the activity enhances upon complexation and the order of activity is in accordance with stability order of metal ions.     

Iron(III) bis-complexes of Schiff bases of S-methyldithiocarbazates: Synthesis,structure, spectral and redox properties and cytotoxicity

A series of iron(III) bis-complexes of the type [FeL₂]X 1-4 , X = OH⁻ ( 1 ), Cl^¯ ( 3 ), and FeCl₄^¯ ( 2 , 4 ), where LH is a tridentate (N,N,S) ligands such as N′-(1-pyridin-2-ylethylidene)-hydrazinecarbodithioic acid methyl ester ( HL1 ), N′-(phenylpyridin-2-ylmethylene)-hydrazinecarbodithioic acid methyl ester ( HL2 ), N′-quinolin-2-ylmethylene-hydrazinecarbodithioic acid methyl ester ( HL3 ), or N′-(1-methyl-1H-imidazol-2-yl-methylene)hydrazinecarbodithioic acid methyl ester ( HL4 ) has been isolated in moderate to good yields and completely characterized by elemental analyses, conductivity studies, and infrared and UV-visible spectral measurements. The single crystal X-ray structures of 1 , 2 and 4 revealed that two deprotonated tridentate (NNS) ligands are meridionally coordinated to constitute a distorted octahedral coordination geometry around iron(III). In acetonitrile solution, all the complexes show quasi-reversible Fe(III)/Fe(II) redox behavior. The in vitro cytotoxicity of the ligands HL1–HL4 (IC₅₀: HL1 , 64.5; HL2 , 51.0; HL3 , 124.0; HL4 , 45.0 μM at 24 h) and complexes 1–4 (IC₅₀: 1 , 84.5; 2 , 40.0; 3 , 168.5; 4 , 50.5 μM at 24 h) towards A549 lung cancer cell lines are similar to cisplatin (69.0 μM), revealing that free ligands cause cancer cell death with potency higher than the corresponding iron(III) complexes. Also, both the ligands and the complexes cause cell death mainly through apoptotic mode, as revealed by the observation of a higher percentage of apoptotic cells in acridine orange (AO)/ ethidium bromide (EB), and Annexin V-Cy3 stained cancer cells.     

Synthesis and characterization of chiral tetraaza macrocyclic nickel(II) and palladium(II) complexes

Chiral tetraaza macrocyclic nickel(II) and palladium(II) complexes 2a-e, containing one or two (R,R)-(-)-1,2-cyclohexanediyl bridges, were synthesized by template condensation reactions and characterized by (1)H and (13)C NMR, IR, UV-vis, and mass spectrometry. The electrophilic reactivity of 2a was explored. Crystal structures of Ni complex 2b and metal-free ligand 5 were determined by single-crystal X-ray diffraction.     

Synthetic,spectral, structural and antimicrobial studies of some Schiff bases 3-d metal complexes

The complexes of tailor made ligands with life essential metal ions may be an emerging area to answer the problems of multi-drug resistance (MDR). The coordination complexes of VO(II), Co(II), Ni(II) and Cu(II) with the Schiff bases derived from 3-bromobenzaldehyde/3-chlorobenzaldehyde with 2-aminophenol have been synthesized and characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, ESR, FAB mass, thermal and magnetic susceptibility measurements, FAB mass and thermal data show degradation of complexes. Both the ligands behave as bidentate coordinating through O and N donor. The complexes exhibit coordination number 4, 5 or 6. X-ray powder diffraction data shows that four (2, 3, 6 and 7) complexes are crystallized in tetragonal system. The in vitro biological screening effects of the investigated compounds were tested against the bacteria Escherichia coli, Staphylococcus aureus and Streptococcus fecalis and the fungi Aspergillus niger, Trichoderma polysporum and Candida albicans by serial dilution method. A comparative study of the MIC values of the Schiff base and their Co(II) (6) and Cu(II) (8) complexes, indicates that the metal complexes exhibit higher or lower antimicrobial activity than the free ligand (L₂).     

Synthesis of chiral linear and macrocyclic candidates: III. Synthesis and antimicrobial activity of linear tetrapeptide and macrocyclic pentapeptide Schiff bases

Russian Journal of General Chemistry - A series of tetrapeptide Schiff bases and a macrocyclic pentapeptide were synthesized using N α-dinicotinoyl-bis[L-leucyl-L-phenylalaninyl acid...     

Synthesis,spectral and thermal properties of macrocyclic zinc(II) complexes

The new zinc ternary complexes [Zn(cyclen)NO₃]ClO4 (I), [Zn₂(cyclen)₂(m-nic)](ClO₄)₃ (II), [Zn₂(cyclen)₂(m-pic)](ClO₄)₃ (III) (cyclen=1,4,7,10-tetraazacyclododecane; nic=nicotinic acid; pic=picolinic acid) were synthesized and their spectral and thermal properties were investigated. The compounds were characterized by elemental analysis, IR spectroscopy and TG/DTG, DTA methods. Moreover, the way of coordination of pyridinecarboxylate anions was proposed on the basis of the spectral data and consequently proved with results of X-ray structure analysis. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis of chiral linear and macrocyclic candidates: VI. Synthesis and antibacterial activity of some macrocyclic tripeptides and linear dipeptide Schiff bases

A series of macrocyclic tripeptides and linear dipeptide Schiff base derivatives has been synthesized using pyridine-3,5-dicarboxylic acid and L-phenyalanine methyl ester as starting materials. Treatment of pyridine-3,5-dicarbonyl dichloride with L-phenylalanine methyl ester gave N,N′-(pyridine-3,5-diyldicarbonyl)bis(L-phenyalanine methyl ester) which was hydrolyzed with 1N sodium hydroxide to the corresponding bis-acid, and the latter was cyclized with diamino acids to afford macrocyclic tripeptide derivatives. The reaction of the bis ester with hydrazine hydrate gave bis-hydrazide, which was condensed with aldehydes to obtain the corresponding Schiff base derivatives. The structures of the newly synthesized compounds were confirmed by IR, ¹H and ¹³C NMR, and MS spectral data and elemental analyses. The antimicrobial activities of some of the newly synthesized compounds were comparable with that of Streptomycin used as control.     

Synthesis of pyrimidine Schiff base transition metal complexes: characterization,spectral and electrochemical analyses,and photoluminescence properties

Research on Chemical Intermediates - This study includes the synthesis, characterization, electrochemical analysis and photoluminescence properties of a Schiff base ligand bearing a pyrimidine ring...     

Binuclear and polynuclear transition metal complexes with macrocyclic ligands. 5. Novel complexes of asymmetric polydentate macrocyclic Schiff bases. Step-by-step synthesis

Reactions of 2,6-bis(3-aminopropylaminocarbonyl)pyridine (1) with 4-tert-butyl-2,6-diformylphenol and 2,5-diformylpyrrole in the presence of Ba(ClO₄)₂ in EtOH afford barium complexes with asymmetric macrocyclic Schiff bases as soft and hard ligands. The reaction of compound 1 with Cu(OCOCMe₃)₂ involves closure of a tetrahydropyrimidine ring to give a mononuclear complex, which was structurally characterized by X-ray diffraction analysis.     

Synthesis and spectral and antibacterial studies of bivalent transition metal ion macrocyclic complexes

A new series of the macrocyclic complexes of type [M(C₁₈H₁₆N₄O₂)X₂], where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and X = Cl⁻, NO₃⁻, CH₃COO₋, has been synthesized by the condensation of succinyldihydrazide with benzil in the presence of bivalent metal ions. The complexes have been characterized with the aid of elemental analyses, conductance measurements, and electronic, NMR, and infrared spectral studies. On the basis of these studies, a six-coordinate distorted octahedral geometry in which two nitrogen and two carbonyl oxygen atoms are suitably placed for coordination toward metal ion has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed remarkable antibacterial activity against some selected bacterial strains.     

Synthesis of new macrocyclic chiral manganese(III) Schiff bases as catalysts for asymmetric epoxidation

We describe a general synthetic strategy for the preparation of a series of macrocyclic chiral manganese(III) salen complexes. The developed reaction pathway allows the modulation of the different key groups, namely, the chiral diimine, the bulky substituents in positions 3 and 3', and the linker used in the macrocyclization of the Schiff base. The different complexes presented here illustrate these readily available structural variations. The catalytic properties of the catalysts (5 mol %) were improved for the asymmetric epoxidation of 2,2'-dimethylchromene with NaOCl or H2O2 as oxygen atom donor. A large range of enantiomeric excesses was obtained (ee values from 30% to 96%), depending on the features and the stability of the complexes. The most efficient catalyst, in terms of stereoinduction (ee value = 96%), contains a diiminocyclohexyl moiety, ethyl groups in positions 3 and 3', and a short polyether junction arm.     

Synthesis,characterization, thermal,and antimicrobial studies of binuclear metal complexes of sulfa-guanidine Schiff bases

A series of metal complexes of Schiff bases derived from condensation of sulfa-guanidine with 1-benzoylacetone (H₂L¹), 2-hydroxybenzophenol (H₂L²), dibenzoylmethane (H₂L³), 5-methylisatine (H₂L⁴), and 1-methylisatine (H₂L⁵) have been synthesized. The complexes are characterized by elemental analysis, molar conductance, magnetic moment measurements, IR, UV–Vis, ¹H NMR, and ESR spectra, as well as thermogravimetric analysis. The low molar conductance values indicate the complexes are nonelectrolytes. IR and ¹H NMR spectra show that H₂L¹–H₂L⁵ are coordinated to metal ions by two bidentate centers. Mn(II), Co(II), Ni(II), and Cu(II) complexes display paramagnetic behavior, whereas the Zn(II)-complex was diamagnetic. All studies confirm the formation of an octahedral geometry for [Cu₂L¹(AcO)₂(H₂O)₆] · 3H₂O (1), [Mn₂L⁴(AcO)₂(H₂O)₆] · 2H₂O (6), [Ni₂L⁴(AcO)₂(H₂O)₆] · 2H₂O (8), a tetrahedral geometry for [Cu₂L²(AcO)₂(H₂O)₂] (2), [Cu₂(L⁴)₂] (4), [Co₂(L⁴)₂] · 2H₂O (7) and [ZnHL⁴(AcO)(H₂O)] · 2H₂O (9) and a trigonal bipyramid geometry for [Cu₂L³(AcO)₂(H₂O)₄] (3) and [Cu₂HL⁵(AcO)₃(H₂O)₃] · H₂O (5). H₂L⁴ was most effective on Gram negative, Gram positive bacteria, and fungi (diameters inhibition zone ranged between 10.5–27.5 mm) after 24 and 48 h, respectively. Complex 8 showed moderate antimicrobial activity. Its minimum inhibitory concentration (MIC) against Escherichia coli, Bacillus subtilis, Candida albicans and Aspargllus flavas was 20 mg L^–1. The compound proved to be of moderate toxicity and its LD₅₀ was 20 mg L^–1.     

4-(二乙氨基)水杨醛席夫碱的合成、光谱性质和热稳定性及量化计算

合成了两种酰腙类席夫碱4-(二乙氨基)水杨醛噻吩-2-甲酰腙(H_2L~1)和4-(二乙氨基)水杨醛异烟酰腙一水合物(H_2L~2·H_2O),利用元素分析、IR光谱、UV光谱和FL光谱及热重分析对其进行了表征.实验结果表明,两种化合物在可见光区均可产生荧光,最大发射峰波长分别为504和525nm.热分解温度分别为254和278℃.用Gaussian 09程序包对H_2L~1进行了量化计算,结果表明,该化合物的水杨基和酰腙基是金属离子很好的配位点.     

Synthesis, structural characterization, and antifungal activity of Schiff bases and their transition metal mixed-ligand complexes

Mixed-ligand complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) have been prepared with biologically active Schiff bases, viz. potassium salt of o-hydroxyacetophenoneglycine [KHL] and bis(benzylidene)ethylenediamine [A¹] or thiophene-o-carboxaldene-p-toluidine [A²]. The synthesized mixed-ligand complexes have been characterized on the basis of elemental analysis, thermogravimetric analysis, magnetic measurements, and electronic and infrared spectra. The mixed-ligand complexes show higher antifungal activity as compared to the free ligands, metal salts, and the control (dimethylsulfoxide) but moderate activity as compared to the standard fungicides (bavistin and emcarb). This text was submitted by the authors in English.     

Synthesis of optically active omeprazole by catalysis with vanadyl complexes with chiral Schiff bases

A new method for the preparation of optically active omeprazole, consisting in asymmetric oxidation of the corresponding sulfide with the use of vanadyl complexes with chiral Schiff bases as the catalysts has been elaborated. The best results of the oxidation were achieved by the use of the combination VO(acac)₂—2-[{(1S,2S,3R,5S)-3-hydroxymethyl-2,6,6-trimethyl-bicyclo[3.1.1]hept-2-ylimino}methyl]phenol—N-ethyl-N,N-diisopropylamine. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1648–1653, August, 2008.