Metal ion complexation by acyclic polyethers with lipophilic amide, thioamide, and amine end groups

A series of acyclic polyethers with lipophilic amide, thioamide, and amine end groups was synthesized. Metal ion transport across bulk liquid membranes and measurement of thermodynamic parameters for ligand-metal ion complexation by titration calorimetry show strong selectivity for complexation of lead ion over other metal ion species for the diamide ligand. Lead ion complexation by the acyclic polyether diamide involves the amide oxygens and silver ion coordination by a dithioamide analog involves the thioamide sulfurs. With a proper length of the ethereal linkage, the ligand wraps around the metal ion in a pseudocyclic fashion.     

Synthesis,characterization and metal ion complexation and extraction capabilities of calix[4]arene Schiff base compounds

The syntheses, characterization and metal ion complexation and extraction capabilities of six new calix[4]arene Schiff base compounds, 5–10, are reported. The preparation of the compounds was achieved by the condensation of 5,17-diamino-11,23-di-tert-butyl-25,27-di-n-butoxy-26,28-dihydroxycalix[4]arene with the appropriate aldehyde (5-bromosalicylaldehyde for 5, 4-anisaldehyde for 6, 4-(dimethylamino)benzaldehyde for 7, 9-anthracenecarboxaldehyde for 8, 1-pyrenecarboxaldehyde for 9, and 9-fluorenecarboxaldehyde for 10) in refluxing ethanol. The compounds were characterized by ¹H and ¹³C NMR spectroscopy, IR spectroscopy, high-resolution mass spectrometry and elemental analysis. The X-ray crystal structures of 7, 8 and 9 (as dichloromethane solvates) revealed that the calixarene molecules adopt H-bond stabilized, distorted-cone conformations and form centrosymmetric dimers in the solid state. Compounds 5–10 did not form host–guest complexes with NEt₄[(bdt)MoO₂(OSiPh₃)] (bdt^2–=benzene-1,2-dithiolate), a potential precursor for biologically relevant oxosulfido-Mo(VI/V) enzyme models; such host–guest complexes have the potential to stabilize these sought-after but highly reactive model compounds. In addition, the capabilities of 5–10 to extract selected metal ions (Ni²⁺, Co²⁺, Cu²⁺, Zn²⁺, Ag⁺, Pb²⁺, Cd²⁺ and Hg²⁺) from an aqueous into an organic phase have been assessed by picrate extraction experiments. Compound 5 displayed exceptional selectivity towards Ni²⁺, compound 7 exhibited enhanced extraction towards all of the metal ions tested and compounds 6, 9 and 10 showed very high selectivity towards Hg²⁺. On the other hand, compound 8 exhibited negligible capacity to extract any of the metal ions tested.     

A Schiff basep-tent-butylcalix[4]arene. Synthesis and metal ion complexation

This communication describes the synthesis of Schiff base calix[4]arene (1) in which the Schiff base unit bridges two opposite hydroxy groups ofp-tert-butylcalix[4]arene. The synthesis of (1) has been achieved by refluxing in acetonitrile-methanol the appropriate 1,3-dicarbaldehyde-p-tert-butyl-calix[4]arene (4) with 1,3-diaminopropane. The yield of the reaction is 19%. Ligand (1) possesses a compartment containing two nitrogen atoms, four ether-type oxygen atoms, and two ionizable hydroxy groups likely to complex metal cations.     

Coordination properties of hydralazine Schiff base Synthesis and equilibrium studies of some metal ion complexes

In the present study, a new ligand is prepared by condensation of hydralazine (1-Hydralazinophthalazine) with 2-butanon-3-oxime. The acid-base equilibria of the schiff-base and the complex formation equilibria with the metal ions as Cu(II), Ni(II), Co(II), Cd(II), Mn(II) and Zn(II) are investigated potentiometrically. The stability constants of the complexes are determined and the concentration distribution diagrams of the complexes are evaluated. The effect of metal ion properties as atomic number, ionic radius, electronegativity and ionization potential are investigated. The isolated solid complexes are characterized by conventional chemical and physical methods. The potential coordination sites are assigned using the i.r. and (1)H NMR spectra. The structures of the isolated solid complexes are proposed on the basis of the spectral and magnetic studies.     

Synthesis and metal ion complexation studies of proton-ionizable calix

A series of novel N-chromogenic calix[4]arene azacrown ethers were synthesized as selective extractants of potassium ion. 1,3-Alternate calix[4]arene azacrown ethers were prepared by reacting 25,27-dipropyloxy-26,28-bis(5-chloro-3-oxapentyloxy) calix[4]arenes with p-toluenesulfonamide in the presence of potassium carbonate. The coupling reaction of calix[4]arene azacrown ether with 2-hydroxy-5-nitrobenzyl bromide in the presence of triethylamine in THF gave the chromogenic calix[4]arene azacrown ether in moderate yield. These compounds show high potassium selectivity over other metal ions as shown by two-phase extraction, bulk liquid membrane, and 1H NMR studies on a ligand-metal complex. It is assumed that the OH of the chromogenic group attached on nitrogen can assist the complexation by encapsulation of the metal.     

Synthesis and genotoxicity of Schiff base transition metal complexes

A new ONNO‐type azomethine ligand, 2,2′‐(ethane‐1,2‐diylidenedinitrilo)dibenzoic acid, (YLH₂) ( 1 ) has been prepared by the condensation of 2‐aminobenzoic acid and glyoxal. The coordination compounds [Ni(YL)] ( 2 ), [Co(YL)] ( 3 ), [Cu(YL)(H₂O)] ( 4 ), [Zn(YL)] ( 5 ), and [Cd(YL)] ( 6 ) of the YLH₂ ligand with five transition metal ions, Ni(II) Co(II), Cu(II), Zn(II), and Cd(II) have been prepared. The structures of these new azomethine compounds are proposed on the basis of the elemental analyses, proton nuclear magnetic resonance, infrared, ultraviolet–visible spectroscopy, and X‐ray powder diffraction patterns. Elemental analyses indicate a ligand metal ratio of 1:1 in the coordination compounds. X‐ray powder diffraction parameters for [Cu(YL)(H₂O)] and [Cd(YL)] compounds correspond to orthorhombic and monoclinic structures, respectively. The ligand acts as a tetradentate ligand bending through oxygen atoms of the hydroxyl groups of benzoic acid and nitrogen atoms of the azomethine groups. In addition, the ligand and its metal complexes have been studied for their possible genotoxic potential. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:119–130, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20665     

Synthesis and properties of podands with 4-antipyryliminomethine groups

Novel podands with 4-antipyryliminomethine groups on benzenes and various numbers of ethers are prepared. According to UV spectroscopy, these compounds form complexes with alkali, alkaline earth, and transition metals. Extraction of metal picrates demonstrated that the podands selectively form extractable complexes with these salts. A lead-selective electrode with an electrode function 22–24 mV/pPb is based on 1,8-bis[2-(4-antipyryliminomethine)phenoxy]-3,6-dioxaoctane. This enables 1·10^–6–1·10^–2 M Pb to be determined in the pH range 3.5–5.5. The electrode is highly selective for Pb in the presence of alkali and alkaline earth metals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2099–2102, September, 1990.     

Synthesis,structural, and biological studies of some bivalent metal ion complexes with the tridentate Schiff base ligand

New complexes of a Schiff base derived from 2-hydroxy-5-chloroacetophenone and glycine with Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and UO₂(VI) have been synthesized. The ligand and the complexes have been characterized on the basis of analytical data, electrical conductance, IR, ESR, and electronic spectra, magnetic susceptibility measurements and thermogravimetric analysis. The ligand acts as a dibasic tridentate (ONO) donor molecule in all the complexes except the Zn(II) complex, where it acts as a monobasic bidentate (OO) donor. Antibacterial activities of the ligand and its metal complexes have been determined by screening the compounds against various Gram(+) and Gram(−) bacterial strains. The solid state d.c. electrical conductivity of the ligand and its complexes has been measured over 313–398 K and the complexes were found to be of semiconducting nature. The article is published in the original.     

Thermodynamics and selectivity of complexation of lithium and sodium thiocyanates with phosphorus-containing podands and compounds modeling the terminal groups of these podands

A series of model compounds and heptadentate neutral phosphorus-containing podands that differ in the conformational rigidity of the terminal groups and in the coordination properties of the phosphoryl groups were synthesized. The thermodynamic parameters of complexation and the cationic selectivity of organophosphorus compounds and podands with respect to LiNCS and NaNCS were studied by calorimetric titration in acetonitrile at 298 K. The reasons for the high selectivity of certain phosphorus-containing podands to the Li⁺ cation are discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1581–1587, September, 1994.This work was financially supported by the Russian Foundation for Basic Research (Grant No. 94-03-08848) and the International Science Foundation (Grant No. MTH000).     

含γ-羟丙基西佛碱型大环四胺的合成研究

本文报道一种由二元伯胺高氯酸盐与3,4-二氢-吡喃-5-醛(3)一步环化缩合合成具有特殊结构的含γ-羟丙基西佛碱型大环四胺(5,6)新的简捷方法, 该法反应条件温和, 产物溶解性能好且易于处理, 产率达52～55% . 在无高氯酸存在的条件下, 脂肪族二元伯胺与3缩合只能得到半关环产物7,8 .     

Synthesis and properties of aromatic poly(ester amide)s with pendant phosphorus groups

Two series of phosphorus‐containing aromatic poly(ester amide)s with inherent viscosities of 0.46–3.20 dL/g were prepared by low‐temperature solution polycondensation from 1,4‐bis(3‐aminobenzoyloxy)‐2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)naphthalene and 1,4‐bis(4‐aminobenzoyloxy)‐2‐(6‐oxido‐6H‐dibenz〈c,e〉〈1,2〉oxaphosphorin‐6‐yl)naphthalene with various aromatic diacid chlorides. All the poly(ester amide)s were amorphous and readily soluble in many organic solvents, such as N,N‐dimethylformamide, N,N‐dimethylacetamide (DMAc), and N‐methyl‐2‐pyrrolidone (NMP). Transparent, tough, and flexible films of these polymers were cast from DMAc and NMP solutions. Their casting films had tensile strengths of 71–214 MPa, elongations to break of 5–10%, and initial moduli of 2.3–6.0 GPa. These poly(ester amide)s had glass‐transition temperatures of 209–239 °C (m‐series) and 222–267 °C (p‐series). The degradation temperatures at 10% weight loss in nitrogen for these polymers ranged from 462 to 489 °C, and the char yields at 800 °C were 55–63%. Most of the poly(ester amide)s also showed a high char yield of 35–45%, even at 800 °C under a flow of air. The limited oxygen indices of these poly(ester amide)s were 35–46. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 459–470, 2002; DOI 10.1002/pola.10129     

Synthesis of lipophilic crown ethers with pendant phosphonic acid or phosphonic acid monoethyl ester groups

Synthetic routes to fifteen lipophilic crown ether phosphonic acid monoethyl esters and nine lipophilic crown ether phosphonic acids are described. For both classes of crown ethers which have pendant, protonionizable groups, the crown ether ring sizes are systematically varied from 12-crown-4 and 24-crown-8.     

Synthesis and physicochemical studies of metal complexes of ferrocene Schiff base derivatives

Two new Schiff bases were prepared by condensing acetylferrocene and 1,1′-diacetylferrocene with S-methyl- dithiocarbazate. Complexes of the two ligands acetylferrocene-1-hydrazono-S-methyldithiocarbazate HmaL and diacetylferrocene-1,1′-dihydrazono-S-methyldithio-carbazate H2daL, with copper(II), nickel(II) and cobalt(II) ions were isolated. The ligands coordinate to the metal ions through either their thioketone or thioenol forms. Both mono- and bis-ligand metal complexes as well as bis-metal complexes of the general formulae: [(H2daL)M]2+, [(daL)M], [(HmaL)2M]2+, [(maL)2M], [(HmaL)2MX2], [(H2daL)M2X4] and [(daL)M2X2] were prepared. All compounds under investigation were characterized and some of their physicochemical properties are reported. This revised version was published online in June 2006 with corrections to the Cover Date.     

Polylactides with aldaric ester end groups or chain extending groups

The synthesis and characterisation of a series of poly(S,S-lactides) and poly(RR/SS-lactides) end capped or chain extended with aldaric ester groups are described. The aldaric esters are prepared from acetyl protected d-gluconolactone, d-galactonolactone and d-mannonolactone by ring opening with butanol or 1,4-butanediol, under acidic conditions. The aldaric esters are fully characterised, including by NMR spectroscopy and mass spectrometry. They are used as co-initiators, with an ethylzinc complex, to enable the controlled ring opening polymerisation of S,S- and rac-lactide. Thus, a series of polylactides are produced with various carbohydrate chain end or extending groups and are fully characterised, including by NMR spectroscopy and gel permeation chromatography (GPC). The polymerisation kinetics are examined, under pseudo first order conditions, and indicate that chain transfer reactions are occurring more rapidly than propagation reactions. The degradation kinetics of the polylactides are examined under acidic conditions; the aldaric esters increase the degradation rates compared to unfunctionalised end groups.     

生色冠醚研究 I: 双偶氮开链冠醚的合成和与金属离子的配位性能

本文用邻苯二酚经过先桥接后偶联,用愈创木酚,水杨醛经过先偶联后桥接的方法,合成了三类双偶氮开链冠醚1,2和3.方法简便,产率较高,借助于可见光谱测定,考查了它们在溶液中与碱金属和碱士金属盐等的配位性能.结果表明,1在95:5四氢呋喃-水(v/v)中,对高氯酸锂和高氯酸钙有良好的选择性变色作用.本文对变色作用的反应机理进行了详细的讨论.可以认为,变色作用的产物是分子内配盐,这已由1与高氯酸钙制成的配合物的元素分析,可见光谱和红外光谱的测定所证明.     

Synthesis,characterization of Schiff base metal complexes and their biological investigation

A new Schiff base ligand named (E)‐2‐(((3‐aminophenyl)imino)methyl)phenol (HL) was prepared through condensation reaction of m‐phenylenediamine and 2‐hydroxybenzaldehyde in 1:1 molar ratio. The new ligand was characterized by elemental analysis and spectral techniques. The coordination behavior of a series of transition metal ions named Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II) and Cd (II) with the newly prepared Schiff base ligand (HL) is reported. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, IR, UV–Vis, ¹H NMR, mass, electronic spectra, magnetic susceptibility and conductivity measurements and further their thermal stability was confirmed by thermogravimetric analysis (TG). From IR spectra, it was observed that the ligand is a neutral tridentate ligand coordinates to the metal ions through protonated phenolic oxygen, azomethine nitrogen and nitrogen atom of NH₂ group. The existence, the number and the position of the water molecules was studied by thermal analysis. The molecular structures of the Schiff base ligand (HL) and its metal complexes were optimized theoretically and the quantum chemical parameters were calculated. The synthesized ligand and its complexes were screened for antimicrobial activities against bacterial species (Staphylococcus aureus and Bacillis subtilis, (gram positive bacteria)), (Salmonella SP., Escherichia coli and Pseudomonas aeruginosa, (gram negative bacteria)) and fungi (Aspergillus fumigatus and Candida albicans). The complexes were found to possess high biological activities against different organisms. Molecular docking was used to predict the efficiency of binding between Schiff base ligand (HL) and both receptors of Escherichia coli (3 T88) and Staphylococcus aureus (3Q8U). The receptor of Escherichia coli (3 T88) showed best interaction with Schiff base ligand (HL) compared to receptor of Staphylococcus aureu (3Q8U).     

Cross-metathesis of allyl halides with olefins bearing amide and ester groups

An investigation was conducted to determine whether the cross-metathesis (CM) of allyl halides tolerates amide groups. The results show that the ruthenium-based complexes I–III serve as poor catalysts for the CM of allyl halides with olefins that contain an N,N-dimethylamide group. In contrast, the Grubbs–Hoveyda–Blechert second generation catalyst (III) efficiently promotes these processes with olefins bearing a Weinreb amide group. Lastly, a reinvestigation of the ester group tolerance of the allyl halide CM with unsaturated esters demonstrated that III serves as an efficient catalyst for these reactions.     

Synthesis and structure of a Schiff base and its bivalent transition metal complexes

A Schiff base (HCSmz) was synthesized via (E)-cinnamaldehyde with S-methyl dithiocarbazate and six bivalent transition metal complexes [M(CSmz)₂] (M=Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, and Hg²⁺) were prepared. The complexes were characterized by elemental analyses, IR, ¹H NMR, and UV-Vis spectra, and the Ni(II) and Zn(II) complexes were also characterized by single crystal X-ray diffraction. After tautomerism of thiotone to thioenol and deprotonization of the thioenol, two ligands chelate the metal by two nitrogens of azomethine and two sulfurs of thioenol. Ni(CSmz)₂ crystallizes in the centrosymmetric space group P2₁ /n with a perfectly square planar trans-configuration with Ni located at the center of the square; crystal packing is stabilized by intra- and intermolecular C–H···S hydrogen bonds. Zn(CSmz)₂ is in the mirror-symmetric space group I4₁ /a in a distorted tetrahedral geometry with two equivalent Zn–N and Zn–S bonds; crystal packing is stabilized by intermolecular C–H···π hydrogen bonds.