New anti‐bacterial polychelates: synthesis,characterization, and anti‐bacterial activities of thiosemicarbazide–formaldehyde resin and its polymer–metal complexes

New polymeric ligand (resin) was prepared by the condensation of thiosemicarbazides with formaldehyde in the presence of acidic medium. Thisemicarbazide–formaldehyde polymer–metal complexes were prepared with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) in 1:2 metal:ligand molar ratio. The polymeric ligand and its polymer–metal complexes were characterized by elemental analysis, thermogravimetric analysis (TGA), FTIR, ¹³C NMR and ¹H NMR. The geometry of central metal ions was conformed by electronic (UV–vis) and EPR spectra. The antibacterial activities of all the synthesized polymers were investigated against Bacillus subtilis and Staphylococcus aureus (Gram‐positive) and Escherichia coli and Salmonella typhi (Gram‐negative). These compounds showed excellent activities against these bacteria using the shaking flask method. Copyright © 2008 John Wiley & Sons, Ltd.     

The complexes of macromolecules and metal nanoparticles: pseudo-template synthesis and behavior

Metal sols composed of metal nanoparticles (1 - 10 nm in diameter) protected with polymer molecules may be regarded as dispersions of polymer-metal complexes formed due to cooperative non-covalent (e.g., hydrophobic, coulombic) interaction of polymer chains with the surface of metal nanoparticles. The sols are commonly prepared by reducing of metal ions in solutions of appropriate polymers. The interactions between macromolecules and nanoparticles are reversible. In the case of long polymer chains and minute particles, the equilibrium constant of the reaction exponentially depends on the surface area of the particle. The probability of mutual “recognition” (complex formation) of growing particle and a macromolecule rapidly increases from practically zero to practically unity in narrow interval of the particle's diameters. The recognition is followed with the shadowing of the particles and the stop of their growths. Such kind of processes was termed “pseudo-template”. In frame of the concept of pseudo-template processes can be estimated: (1) the conditions at which sol particles of desirable size can be prepared, (2) the influence of temperature, polymer concentration, nanoparticles size, and other conditions on the stability of polymer - particle complex having been prepared, and (3) the conditions at which stable sol does not exist and can not be prepared at all. The interactions between metal nanoparticles and macromolecules are highly selective regard to the structure of polymer chains. The property can be effectively used for the control the size characteristics of metal nanoparticles (in course of their formation) and the stability of metal sols. The selectivity provides high conversions in catalytic chemical modification reactions in which a macromolecule is the substrate and a component of the catalyst in the same time. As an example, the hydrolysis of lactame groups in monomer unites of poly(N-vinyl pyrrolidone) catalyzed with copper sols is discussed.     

A Homotelechelic bis‐terpyridine macroligand: One‐step synthesis and its metallo‐supramolecular self‐assembly

A homotelechelic macroligand bearing two 2,2′:6′,2″‐terpyridin‐4′‐yl units, as chain ends, is used as building block for the preparation of a linear metallo‐supramolecular chain‐extended polymer. The macroligand has been prepared by nitroxide‐mediated polymerization (NMP) of styrene using a bis‐terpyridine‐functionalized NMP initiator. The controlled character of the NMP process has been confirmed by detailed characterization of the polymer by size‐exclusion chromatography, nuclear magnetic resonance spectroscopy as well as mass spectrometry. Subsequently, the self‐assembly with Fe^II ions into the chain‐extended metallopolymer and the disassembly thereof, in the presence of a strong competitive ligand, has been studied by UV–vis absorption spectroscopy and diffusion‐ordered NMR spectroscopy. The reversibility of the formation of the metallo‐supramolecular material, when addressed by external stimuli, could be proven. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

In vitro antibacterial and antifungal assay of poly‐(ethylene oxamide‐N,N′‐diacetate) and its polymer–metal complexes

A new polyester, poly‐(ethylene oxamide‐N,N′‐diacetate) (PEODA), containing glycine moiety was synthesized by the reaction of oxamide‐N,N′‐diacetic acid and ethylene glycol and its polymer–metal complexes were synthesized with transition metal ions. The monomer oxamide‐N,N′‐diacetic acid was prepared by the reaction of glycine and diethyl oxalate. The polymer and its metal complexes were characterized by elemental analysis and other spectroscopic techniques. The in vitro antibacterial activities of all the synthesized polymers were investigated against some bacteria and fungi. The analytical data revealed that the coordination polymers of Mn(II), Co(II) and Ni(II) are coordinated with two water molecules, which are further supported by FTIR spectra and TGA data. The polymer–metal complexes showed excellent antibacterial activities against both types of microorganisms; the polymeric ligand was also found to be effective but less so than the polymer–metal complexes. On the basis of the antimicrobial behavior, these polymers may be used as antifungal and antifouling coating materials in fields like life‐saving medical devices and the bottoms of ships. Copyright © 2007 John Wiley & Sons, Ltd.     

The synthesis and antitumor activity of metal complexes of amine–carboxyborane adducts

The amine carboxyborane metal complexes, tetrakis - μ - (trimethylamine – boranecarbo - xylato)acetonitrile dicopper(II) and bis-μ- (morpholine–boranecarboxylato)zinc(II) dihydrate demonstrated cytotoxic activity against human Tmolt₃, HeLa-S³ and MB-9812 cell growth.Tetrakis-μ-(trimethylamine–boranecarboxylato)-acetonitrile dicopper(II) and bis - μ - (morpholine – boranecarboxylato)zinc (II) dihydrate inhibited L₁₂₁₀ DNA, RNA and protein syntheses, with greatest inhibitory effects on DNA synthesis. The reduction in DNA synthesis correlates well with inhibition of de novopurine synthesis and the key enzymes involved in this pathway, i.e. IMP dehydrogenase and PRPP amido transferase. These compounds were also observed to induce DNA strand scission but did not appear to intercalate between base pairs of DNA, alkylate bases or cause cross-linking of the strands of DNA. Tetrakis-μ-(trimethylamine – boranecarboxylato)acetonitrile dicopper(II) also demonstrated the ability to inhibit L₁₂₁₀ DNA topoisomerase II activity. © 1998 John Wiley & Sons, Ltd.     

Amphiphilic mesogen‐jacketed liquid crystalline polymers: Design,synthesis, and self‐assembly behaviors

We synthesized a series of amphiphilic mesogen‐jacketed liquid crystalline (LC) polymers with a biphenyl side‐chain mesogen containing a carboxylic acid group on one side and an octyloxy group on the other, and the number of methylene units between the biphenyl core and the exterior carboxylic acid group was varied to adjust the mesophases and the amphiphilic nature. The polymers were obtained through conventional radical polymerizations and characterized by a combination of different techniques such as thermogravimetric analysis, differential scanning calorimetry, polarized light microscopy, and X‐ray scattering. The results revealed that the polymer without any methylene spacer, POBP‐0C, did not exhibit LC properties while POBP‐1C (n = 1) and POBP‐7C (n = 7) formed double layer smectic A (S_A) phases. The hydrogen bonding among the carboxylic acid groups and the segregation between the carboxylic acid groups and the alky chains played important roles in forming the mesophases. In addition, the solution self‐assembly behaviors were also preliminarily investigated through the fluorescent probe technique and transmission electron microscopy, and vesicles with uniform sizes were observed. The weak hydrophilicity and large degree of freedom of the carboxylic acid group and the relative rigidity of the polymer chain due to the “jacketing” effect were responsible for the formation of the structures. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Two novel benzenedicarboxylate‐metal complexes: synthesis,crystal structures and fluorescent properties

Two novel benzenedicarboxylate–metal complexes, [Sm(nphth)(Hnphth)(H₂O)₃^?H₂O]₂ and [Zn(nphth)(bipy)(H₂O) ?H₂O]₂ (2) (H₂nphth = 3‐nitrophthalic acid, bipy = 2,2′‐bipyridine), have been synthesized under hydrothermal condition and characterized by single‐crystal X‐ray diffraction. Both complex 1 and 2 exhibit a dimeric structure, and nphth ligand shows different coordination mode in the f‐block and d‐block complexes. The fluorescent properties of two complexes are investigated; the results reveal that the two complexes show different kinds of fluorescence. Copyright © 2007 John Wiley & Sons, Ltd.     

Polystyrene with Pendant Mixed Functional Ruthenium(II)‐Terpyridine Complexes

A vinyl substituted 2,2′:6′,2″‐terpyridine and a mixed, bifunctional ruthenium(II)‐terpyridine complex bearing a vinyl and a hydroxymethyl group are utilized as comonomers for radical copolymerization with styrene. The resulting polymers are characterized by means of UV‐vis spectroscopy and gel permeation chromatography, coupled with an in‐line diode array spectrophotometer.     

One‐Step Multicomponent Self‐Assembly of a First‐Generation Sierpiński Triangle: From Fractal Design to Chemical Reality

A novel terpyridine‐based architecture that mimics a first‐generation Sierpiński triangle has been synthesized by multicomponent assembly and features tpy? Cd^II? tpy connectivity (tpy=terpyridine). The key terpyridine ligands were synthesized by the Suzuki cross‐coupling reaction. Mixing two different terpyridine‐based ligands and Cd^II in a precise stoichiometric ratio (1:1:3) produced the desired fractal architecture in near‐quantitative yield. Characterization was accomplished by NMR spectroscopy, mass spectrometry, and transmission electron microscopy.     

Chelate polymers: II. Some novel transition metals complexes with azomethine‐containing siloxanes and their polyesters

New Schiff bases of 2,4‐dihydroxybenzaldehyde with siloxane‐α,ω‐diamines having different numbers of siloxane units in the chain have been synthesized and characterized by spectroscopy, elemental and thermal analyses. These azomethines were found to form complexes readily with copper(II), nickel(II), cobalt(II), cadmium(II) and zinc(II). From IR and UV–Vis studies, the phenolic oxygen and imine nitrogen of the ligand were found to be the coordination sites. Thermogravimetric analysis (TGA) data indicate the chelates to be more stable than the corresponding ligands. The melting points increase with shortening of the siloxane segment from azomethine, as well as the result of complexation. The chelates obtained were covalently inserted in polymeric linear structures by polycondensation through the OH‐difunctionalized ligand with 1,3‐bis(carboxypropyl)tetramethyldisiloxane. Direct polycondensation, assisted either by acetic anhydride or N,N′‐dicyclohexylcarbodiimide as dehydrating agent and the complex 4‐(dimethylamino)pyridinium 4‐toluenesulfonate as catalyst, was used for the synthesis of these compound types. The structures of the polymers obtained were confirmed by IR, UV and ¹H NMR. Characterization was undertaken by TGA, solubility tests and viscosity measurements. Copyright © 2003 John Wiley & Sons, Ltd.     

Molecular mechanics calculations of β‐diketonate,aqua, and aqua‐β‐diketonate complexes of lanthanide ions using Gillespie–Kepert model

A version of molecular mechanics based on the Gillespie–Kepert model of coordination bonds “repulsion” is applied to lanthanide complexes. The force field parameters are developed that describe the structure of β‐diketonate‐, aqua‐, and mixed aqua‐β‐diketonate complexes with good accuracy; the same parameters are applicable to various coordination numbers/polyhedra. For the aqua complexes, typical root‐mean‐square deviation (calculated vs. X‐ray experimental values) is 0.02 Å in Ln–O bond lengths and 2.0° in O–Ln–O valence angles. For most of the other compounds, the same precision is achieved in coordination bond lengths, while 3.5° is a typical precision for coordination bond angles. Calculations successfully reproduce the puckering of the β‐diketonate chelate rings, as well as the relative stability of isomers for a representative example. © 2000 John Wiley & Sons, Inc. J Comput Chem 22: 38–50, 2001     

Radiation-induced graft polymerization of acrylic acid onto fluorinated polymers. II. Graft copolymer–metal complexes obtained by radiation grafting onto poly(tetrafluoroethylene-ethylene) copolymer

A study has been made on the graft copolymers obtained by radiation-induced grafting of acrylic acid onto poly(tetrafluoroethylene-ethylene) (ET) films. The conversion of the graft copolymer into metal acrylate copolymer complex was carried out by treatment with different metal salts. Such a prepared graft copolymer–metal complex was confirmed by different methods: IR, UV spectrometry, degree of coloration, and x-ray fluorescence. Some selected properties of the graft copolymer–metal complexes such as electrical conductivity, swelling behavior, and mechanical properties were investigated. The influence of metal complexes in the graft copolymers was determined and compared with the grafted films. The possibility of the practical uses for such prepared graft copolymer–metal complexes was discussed and determined. It was assumed that such materials may be of great interest in the field of semiconducting materials in addition to their applicability as cation-exchange membranes. © 1993 John Wiley & Sons, Inc.     

Induction of Optical Activity in an Oligothiophene Synchronized with pH‐Sensitive Folding of Amylose

Control of the helical sense in α‐sexithiophene (6T) through pH‐responsive wrapping with left‐handed‐helical amylose is demonstrated. A change in pH of the medium caused a significant conformational change in amylose as the host polymer, which resulted in either supramolecular complexation with 6T as the guest molecule to induce optical activity or decomplexation leading to loss of optical activity. Furthermore, we observed that chirality reversal in 6T does not require hosts of opposite helical chirality, but can be made possible simply by taking advantage of the pH sensitivity of the amylose folding, which is dependent on the pH history of the aqueous medium. In helical amylose, 6T assumes a clockwise‐twisted conformation when the pH is changed from acidic to neutral, but assumes an anticlockwise‐twisted conformation when the aqueous solution is acidified from very basic conditions.     

Metalloantibiotics: synthesis and antibacterial activity of cefepime metal complexes

Cefepime interacts with transition metal(II) ions to give [M(cefepime)Cl₂] complexes (M = Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)) which were characterized by physicochemical and spectroscopic methods. The complexes are insoluble in water and common organic solvents, and probably have polymeric structures. The spectra indicated that the ligand is a multidentate chelating agent. The complexes have been screened for antibacterial activity against several bacteria and showed activity less than that of free cefepime.     

Synthesis of self‐healing supramolecular rubbers from fatty acid derivatives,diethylene triamine,and urea

We describe the synthesis of supramolecular self‐healing elastomers from vegetable oil fatty acid derivatives, diethylene triamine, and urea. Our strategy to obtain materials that are self‐healing but do not flow relies on the use of a wide molecular distribution of randomly branched oligomers equipped with self‐complementary and complementary hydrogen bonding groups. We prepared such oligomers with a two steps procedure. In the first step, diethylene triamine was condensed with dimer acids. In the second step, the oligomers obtained were allowed to react with urea. The molecules were characterized by NMR and IR spectroscopies and Monte‐Carlo simulations were used to analyze the molecular size distribution. The sensitivity to small variations of the experimental conditions has been examined and the robustness of the synthetic procedure optimized. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7925–7936, 2008     

Native Mannose‐Dominant Extraction by Pyridine–Phenol Alternating Oligomers Having an Extremely Efficient Repeating Motif of Hydrogen‐Bonding Acceptors and Donors

Pyridine–phenol alternating oligomers in which pyridine and phenol moieties are alternatingly linked through acetylene bonds at the 2,6‐positions of the aromatic rings were designed and synthesized. The pyridine nitrogen atom and the neighboring phenolic hydroxyl group were oriented so that they do not form an intramolecular hydrogen bond but cooperatively act as hydrogen‐bonding acceptor and donor in a push–pull fashion for the hydroxyl group of saccharides. The longer oligomer strongly bound to lipophilic glycosides in 1,2‐dichloroethane, and association constants approached 10⁸ M ^?1. Moreover, the oligomer extracted native saccharides from a solid phase to apolar organic solvents up to the extent of an equal amount of the oligomer and showed mannose‐dominant extraction among naturally abundant hexoses. The oligomer bound to native saccharides even in 20 % DMSO‐containing 1,2‐dichloroethane and exhibited association constants of greater than 10 M ^?1 for D ‐mannose and D ‐glucose.     

Polymer‐supported metal complexes as antibacterial agents: synthesis,characterization and thermal degradation kinetics

Polymeric metal complexes were prepared using a synthesized novel terpolymer ligand involving anthranilic acid–o‐toluidine–formaldehyde by a polycondensation technique. The synthesized ligand and its metal complexes were characterized using elemental analysis and molar conductivity measurements, and FT‐IR, electronic, electron spin resonance and NMR (¹H and ¹³C) spectral methods. The surface morphology and the nature of the synthesized compounds were examined using scanning electron microscopy and X‐ray diffraction. The thermal stabilities of the ligand and its metal complexes were determined using thermogravimetric analysis (TGA). From the TGA results, various kinetic parameters, i.e. activation energy and order of reaction, and thermodynamic parameters, i.e. entropy change, apparent entropy, frequency factor and free energy change, were determined using the Freeman–Carroll and Sharp–Wentworth methods. In addition, a thermal degradation model was also proposed using the Phadnis–Deshpande method. The thermal stability of the ligand and its metal complexes was found to be appreciably high; in particular, the ligand showed very high stability compared to its metal complexes due to intramolecular hydrogen bonding. Furthermore, the synthesized compounds were subjected to in vitro antibacterial studies with various microorganisms. The results of the studies confirmed that the compounds showed better antibacterial results than a standard antibacterial drug. Copyright © 2014 John Wiley & Sons, Ltd.     

Triphenylamine‐based fluorescent conjugated copolymers with pendant terpyridyl ligands as chemosensors for metal ions

Two well‐defined triphenylamine‐based fluorescent conjugated copolymers with pendant terpyridyl ligands were synthesized through Suzuki coupling polymerization and were further characterized by ¹H‐NMR, ¹³C‐NMR, gel permeation chromatography, Infrared, and UV‐vis spectra. Polymer P‐1 , terpyridine‐bearing poly(triphenylamine‐alt‐fluorene) with a high fluorescence quantum yield (62%) shows much higher sensitivities toward Fe³⁺, Ni²⁺, and Cu²⁺ as compared with the other metal ions investigated. Especially, Fe³⁺ can lead to an almost complete fluorescence quenching of polymer P‐1 . Whereas, the analogous polymer P‐2 , in which N‐ethylcarbazole repeat units replace the fluorene units in P‐1 , shows a very poor selectivity. It demonstrates that polymers with a same receptor may show different sensitivity to analytes owing to their different type of backbones. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1310–1316, 2010