Nonaqueous dispersion polymerization of styrene in methanol with the ionomer block copolymer poly[(4‐methylstyrene)‐co‐(4‐vinyltriethylbenzyl ammonium bromide)]‐b‐polyisobutene as a stabilizer

The nonaqueous dispersion polymerization of styrene in methanol with poly[(4‐methylstyrene)‐co‐(4‐vinyltriethylbenzyl ammonium bromide)]‐b‐polyisobutene as a stabilizer was investigated. There was no observable inducing period or autoacceleration in the polymerization process. The conversion increased almost linearly with the polymerization time as high as 80%. The average sizes of the obtained polystyrene particles increased, and the size distributions of the polystyrene particles tended to become narrower, with increasing conversion. The mechanism of the dispersion polymerization in the presence of polyisobutene‐b‐poly[(4‐methylstyrene)‐co‐(4‐vinyltriethylbenzyl ammonium bromide)] was nucleation/growth. When the stabilizer/monomer ratio (w/w) was greater than 2.0%, the polystyrene dispersion was stable, and there was no observable polymer particle coagulation taking place during the whole polymerization process. The average diameter of the polymer particles can be mediated through changes in the polymerization conversion, monomer, and stabilizer. Nearly monodispersed polystyrene particles with average diameters of approximately 0.45–2.21 μm were obtained under optimal conditions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2678–2685, 2004     

A facile preparation of microparticles from sulfonated polyester nanoparticles via emulsion–aggregation process

A process to prepare microparticles of narrow size distribution having a particle size in the range of approximately 1–8 μm was developed. The primary objective of this work was to study the formation and morphology of copolyester microparticles prepared using a sulfonated copolyester emulsion by an emulsion–aggregation process. Molecular weight of the copolyesters was measured by gel permeation chromatography. The glass transition temperature (T_g) of the copolyesters was found to be in the range of 40–70 °C. Aggregating agents used in this study were 1–5% (wt.%) solutions of divalent ions of zinc acetate and magnesium chloride salts. Emulsion–aggregation experiments were performed at various temperatures: 40, 50, 60, and 80 °C. Particle morphologies studied by field emission-scanning electron microscopy measurements provided an understanding of the conditions and mechanism leading to formation of microparticles by the emulsion–aggregation process. Molecular weight and T_g of the copolyester, the concentration of aggregating agent, and the temperature were determined to be the most important parameters influencing the preparation of microparticles. This process illustrates the preparation of microparticles of uniform size with morphology of controlled shape from a nanometer-sized emulsion by ionic crosslinking.     

Antibacterial and antibiofilm activity of nanochelating based silver nanoparticles against several nosocomial pathogens

The emergence of multi‐drug resistant (MDR) bacteria and dynamic pattern of infectious diseases demand to develop alternative and more effective therapeutic strategies. Silver nanoparticles (AgNPs) are among the most widely commercialized engineered nanomaterials, because of their unique properties and increasing use for various applications in nanomedicine. This study for the first time aimed to evaluate the antibacterial and antibiofilm activities of newly synthesized nanochelating based AgNPs against several Gram‐positive and ‐negative nosocomial pathogens. Nanochelating technology was used to design and synthesize the AgNPs. The cytotoxicity was tested in human cell line using the MTT assay. AgNPs minimal inhibitory concentration (MIC) was determined by standard broth microdilution. Antibiofilm activity was assayed by a microtiter‐plate screening method. The two synthesized AgNPs including AgNPs (A) with the size of about 20‐25 nm, and AgNPs (B) with 30‐35 nm were tested against Staphylococcus aureus, Staphylococcus epidermidis, Acinetobacter baumannii, and Pseudomonas aeruginosa. AgNPs exhibited higher antibacterial activity against Gram‐positive strains. AgNPs were found to significantly inhibit the biofilm formation of tested strains in concentration 0.01 to 10 mg/mL. AgNPs (A) showed significant effective antibiofilm activity compared to AgNPs (B). In summary, our results showed the promising antibacterial and antibiofilm activity of our new nanochelating based synthesized AgNPs against several nosocomial pathogens.     

Synthesis,Characterization, and Antimicrobial Screening of 4″‐methyl‐2,2″‐diaryl‐4,2′:4′,5″‐terthiazole Derivatives

A series of novel 4″‐methyl‐2,2″‐diaryl‐4,2′:4′,5″‐terthiazole ( 8a‐p ) derivatives has been synthesized and screened for antibacterial activity against four pathogenic bacteria, Escherichia coli, Pseudomonas flurescence, Staphylococcus aureus, and Bacillus subtilis. Among them, compounds 8a and 8j exhibited excellent antibacterial activity with minimum inhibitory concentration range of 1.0 to 5.3 μg/mL and compounds 8m and 8p exhibited moderate to good antibacterial activity with minimum inhibitory concentration range of 16.9 to 29.7 μg/mL against all tested strains. All the synthesized compounds were screened for their in vitro antifungal activity against Cocinida candida. Most of the compounds reported moderate antifungal activity. This study provides valuable directions to our ongoing endeavor of rationally designing more potent antimicrobial agent.     

Hydrophilic magnetic polymer latexes. 2. Encapsulation of adsorbed iron oxide nanoparticles

The encapsulation of seed polymer particles coated by anionic iron oxide nanoparticles has been investigated using N-isopropylacrylamide as a main monomer, N,N-methylene bisacrylamide as a crosslinking agent, itaconic acid as a functional monomer and potassium persulfate as an anionic initiator. The magnetic latexes obtained have been characterized with regard to particle size, iron oxide content and electrophoretic mobility. All these properties have been examined by varying several polymerization parameters: reaction medium, monomer(s) and crosslinking agent concentrations, nature of seed latexes and type of polymerization (batch versus shot process). The magnetic content in the polymer microspheres strongly depends on the polymerization procedure (i.e., encapsulation process) and varies between 6 and 23 wt%, and monodisperse magnetic polymer particles were obtained. Received: 28 December 1999 Accepted in revised form: 15 June 1999     

Polymeric phosphonium salts as a novel class of cationic biocides. V. Synthesis and antibacterial activity of polyesters releasing phosphonium biocides

Polyesters were prepared which retained phosphonium biocides as counter ions of sodium sulfonate moieties incorporated into the polymers, and surface antibacterial activity of the polyester films against Staphylococcus aureus and Escherichia coli was explored. These films exhibited a high surface antibacterial activity against S. aureus and E. coli, particularly against S. aureus, and the activity was affected by the structure and the compositional ratio of the phosphonium salts. Amount of the released phosphonium salts was very small, so that liberation of the phosphonium biocides can be expected to occur over a long period. Morphological changes of the cells of S. aureus and E. coli in contact with the polyester films were evaluated by scanning electron microscopy. It was found that the surface antibacterial activity of the polyester films was rather bacteriostatic than bactericidal as evidenced by no morphological changes of the bacterial cells in contact with the phosphonium biocides © 1993 John Wiley & Sons, Inc.     

Release properties of chemical and enzymatic crosslinked gelatin-gum Arabic microparticles containing a fluorescent probe plus vetiver essential oil

Oil-containing gelatin-gum Arabic microparticles were prepared by complex coacervation followed by crosslinking with glutaraldehyde or transglutaminase. A fluorescent mixture, khusimyl dansylate (KD) as the fluorescent compound mixed to the vetiver essential oil, was used as oil model. The effect of the type of crosslinking of the coacervated gelatin-gum Arabic membrane, the physical state of microparticles, wet or freeze-dried and the type of release media, aqueous with surfactants, Sodium Dodecyl Sulphate (sds) or Tween 80 (tw) and anhydrous ethanol as organic media on the release rate of the KD from the microparticles, was experimentally investigated.It was shown that the oil was dispersed uniformly throughout the microparticles and the chemical crosslinked microparticles were more resistant to swelling, presenting smaller sizes after hydration. Also the crosslinking effect, transglutaminase or glutaraldehyde, could be confirmed by the integrity of the crosslinked gelatin-gum Arabic microparticles after incubation in the aqueous sds media, compared to complete dissolution of the uncrosslinked microparticles in this media.The cumulative fluorescent KD release from the gelatin-gum Arabic microparticles decreased in the following order of dissolution media: anhydrous ethanol > tw > sds and the wet microparticles have shown a faster KD release than freeze-dried ones. A mathematical model was used to estimate the diffusion coefficient (D). The chemically crosslinked gelatin-gum Arabic microparticles ensured a pronounced retard effect in the KD diffusion, presenting a D varying from 0.02 to 0.6 × 10⁻¹¹ cm²/s, mainly in an aqueous media, against D varying from 1.05 to 13.9 × 10⁻¹¹ cm²/s from the enzymatic crosslinked microparticles.     

Effect of the reaction parameters on the particle size in the dispersion polymerization of 2‐hydroxyethyl and glycidyl methacrylate in the presence of a ferrofluid

The precipitation of Fe₃O₄ from an aqueous solution with ammonium hydroxide produced nanoparticles that were coated with a layer of oleic acid [or, in some cases, poly(ethylene oxide) or poly(vinylpyrrolidone)] before their dispersion into the organic phase. The encapsulation of magnetite nanoparticles in poly(2‐hydroxyethyl methacrylate) or poly(2‐hydroxyethyl methacrylate‐co‐glycidyl methacrylate) microparticles was achieved by dispersion polymerization in toluene/2‐methylpropan‐1‐ol. Magnetic poly(glycidyl methacrylate) microparticles were obtained in the presence of poly(ethylene oxide) at the magnetite/monomer interface. The particles containing up to 20 wt % iron maintained their discrete nature and did not aggregate. The effect of the reaction medium polarity, the concentrations of the monomer, initiator, and stabilizer, and the temperature on the particle size, particle size distribution, and iron and oxirane group contents was studied. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1848–1863, 2003     

The effect of covalent surface immobilization on the bactericidal efficacy of a quaternary ammonium compound

This study investigates the effect of surface immobilization on the bactericidal function of a quaternary ammonium compound. Quaternary ammonium silane (QAS) coated planar surfaces did not produce any measurable mortality of Staphylococcus aureus, while 1 µm QAS‐coated microparticles did produce S. aureus mortality. The experiments using QAS‐coated microparticles indicate that the ability of QAS molecules to disrupt the cell wall is not hindered by covalent immobilization of QAS to a surface. These results provide evidence that S. aureus cells on a QAS‐coated planar surface are not exposed to a sufficient number of QAS molecules to produce significant mortality. This result has important implications for the development of self‐decontaminating coatings. Covalent immobilization is used to prevent leaching of the bactericidal compound. However, covalent immobilization may result in a significant tradeoff in bactericidal performance. Published in 2007 by John Wiley & Sons, Ltd.     

Ultrasonic‐assisted synthesis and biological evaluation of a nano‐rod diorganotin phosphonic diamide: Precursor for the fabrication of SnP2O7 nano‐structure

Nanorods of a diorganotin phosphonic diamide with formula [Sn(CH₃)₂(Cl)₂(L)₂]{L = C₆H₅(O)P(NHC₆H₁₁)₂} have been synthesized by sonochemical processes at different concentrations without any surfactant or capping agent. The structure and morphology of the prepared complex were investigated by using SEM‐EDAX, XRD, DLS, UV–Vis and FT‐IR spectroscopy. Nanoparticles with well‐defined rod shapes and sizes in the range 30–40 nm have been obtained. Also bulk form of the titled complex was synthesized and characterized by ¹H, ¹³C, ³¹P, ¹¹⁹Sn NMR, UV–Vis and FT‐IR spectroscopy and compared with its nano‐size. The thermal stabilities at bulk and nano‐size scale have been studied by thermal gravimetric (TG) and differential thermal analysis (DTA). Further, SnP₂O₇ nanoparticles were synthesized by direct calcination at 730 °C under air atmosphere and characterized using XRD, SEM, and TEM. From XRD measurements, we determined the mean size of the crystallites about 27.4 nm. It is found that the size and morphology of the tin pyrophosphate nano‐structures are dependent upon the particles size of precursor compound as well. Two different forms of metal coordination compound (1a, 1b) and the corresponding ligand (L) were screened for their antibacterial activity against the selected Gram‐positive and Gram‐negative bacteria, showing bactericidal activity for complexes 1a and 1b. In vitro cytotoxicity of compounds was studied against human carcinoma cell lines, A2780 (ovarian cancer) and PC‐3 (prostate cancer). Results indicated that 1a and 1b possess relatively strong cytotoxic activity against cancer cells with IC₅₀ values ranging from 93.2 to 376.2 μM for two exposure time (24 and 48 h).     

Influence of the catalyst on monomer insertion in the syndiospecific copolymerization of styrene and para‐methylstyrene

The effect of the kind of transition‐metal catalyst on the extent of comonomer insertion in the syndiospecific complex‐coordinative copolymerization of styrene and para‐methylstyrene has been investigated. The results for the influence of the polymerization conditions have shown that there is no real difference between solution copolymerization in toluene and solvent‐free styrene copolymerization in bulk, with respect to the reactivity ratio for para‐methylstyrene (r₂), under comparable conditions in the presence of methylaluminoxane and triisobutylaluminum and at low polymerization conversions. All the investigated catalysts lead to a preferred incorporation of para‐methylstyrene into the polymer chain in comparison with styrene and over the whole range of monomer compositions. The increasing capability of the different catalysts to provide copolymers with enhanced para‐methylstyrene concentrations can be summarized by the increasing r₂ values for the copolymerization in bulk as follows: η⁵‐pentamethylcyclopentadienyl titanium trichloride < η⁵‐octahydrofluorenyl titanium trimethoxide < η⁵‐octahydrofluorenyl titanium tristrifluoroacetate < η⁵‐cyclopentadienyl titanium(N,N‐dicyclohexylamido)dichloride < η⁵‐cyclopentadienyl titanium trichloride. For a correlation between the catalyst structure and the comonomer insertion, the catalysts can be described by electronic effects (electrostatic charge of the transition‐metal atom) and steric effects (minimum structural cone angle). The results show that the steric properties of the transition‐metal complexes have the most important effect on the insertion of para‐methylstyrene into the copolymer. If the minimum structural cone angle of the ligand of the transition‐metal catalyst decreases, the incorporation of the comonomer para‐methylstyrene increases significantly. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2061–2067, 2005     

Preparation and Antibacterial Function of Quaternary Ammonium Salts Grafted Cellulose Fiber Initiated by Fe2 +-H2O2 Redox

The surface contact disinfecting technique is a newly developed method for water sterilization. In this paper, the grafted quaternary ammonium salts (QAS) antibacterial fibers were prepared and designed to apply for the surface contact disinfecting process in water treatment. The antibacterial fibers were directly prepared by grafting methacryloxylethyl benzyl dimethyl ammonium chloride (DMAE-BC) onto cellulose fiber using thiocarbonate-H₂O₂ redox system. All kinds of factors in the grafting reactions, such as reaction time, reaction temperature, monomer concentration, initiator concentration, which influence the percentage of grafting, were studied and optimized. The modified cellulose fibers were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope(SEM). The effects of the percentage of grafting of the grafted cellulose fibers on bactericidal activity were also studied. The spread plate method was used to characterize the bactericidal activity. The disinfection process was further investigated by directly observing the morphology of the bacterial cells adsorbed on the antibacterial fibers with SEM and measuring extracelluar total protein concentration in suspension. The poly(DMAE-BC)-grafted cellulose ?ber was found to exhibit particularly high activity against E.coli.     

DNA interaction,antimicrobial and molecular docking studies of biologically interesting Schiff base complexes incorporating 4‐formyl‐N,N‐dimethylaniline and propylenediamine

Four new transition metal complexes incorporating a Schiff base ligand derived from propylenediamine and 4‐formyl‐N ,N ‐dimethylaniline have been synthesized using transition metal salts. The characterization of the newly formed complexes was done from physicochemical parameters and using various techniques like ¹H NMR, ¹³C NMR, IR, UV, electron paramagnetic resonance and mass spectroscopies, powder X‐ray diffraction and magnetic susceptibility. All the complexes were found to be monomeric in nature with square planar geometry. X‐ray powder diffraction illustrates that the complexes have a crystalline nature. The interaction of metal complexes with calf thymus DNA was investigated using UV–visible absorption, viscosity measurements, cyclic voltammetry, emission spectroscopy and docking analysis. The results indicate that the Cu(II), Co(II), Ni(II) and Zn(II) complexes interact with DNA by intercalative binding mode with optimum intrinsic binding constants of 4.3 × 10⁴, 3.9 × 10⁴, 4.7 × 10⁴ and 3.7 × 10⁴ M⁻¹, respectively. These DNA binding results were rationalized using molecular docking in which the docked structures indicate that the metal complexes fit well into the A‐T rich region of target DNA through intercalation. The metal complexes exhibit an effective cleavage with pUC19 DNA by an oxidative cleavage mechanism. The synthesized ligand and the complexes were tested for their in vitro antimicrobial activity. The complexes show enhanced antifungal and antibacterial activities compared to the free ligand.     

Preparation and properties of antibacterial ABS plastics based on polymeric quaternary phosphonium salts antibacterial agents

Antibacterial acrylonitrile‐butadiene‐styrene (ABS) plastics were prepared by adding polymeric quaternary phosphonium salts as antibacterial agents through a double screw extruder. The novel polymeric quaternary phosphonium salts (PBrMAP‐n) with alkyl chain length ranging from 3 to 11 were synthesized, and their chemical structures were confirmed by Nuclear magnetic resonance hydrogen spectroscopy (¹H‐NMR) and Fourier transform infrared spectroscopy (FT‐IR) spectra. The thermogravimetric analysis (TGA) results showed that all of the antibacterial agents had good thermal stability. The influence of addition amount as well as the alkyl chain length on mechanical properties and antibacterial properties was investigated. Compared with the pure ABS, all of PBrMAP‐n containing specimens had comparable tensile strength and flexural properties but reduced impact strength. Only samples with 10 wt% of PBrMAP‐11 exhibited more than 90% antibacterial efficiency against Escherichia coli and Staphylococcus aureus.     

Green synthesis and chemical characterization of silver nanoparticles from aqueous extract of Falcaria vulgaris leaves and assessment of their cytotoxicity and antioxidant,antibacterial, antifungal and cutaneous wound healing properties

Nanotechnology encompasses the understanding of the fundamental physics, biology, chemistry and technology of nanometre‐scale objects. In recent decades, nanotechnology has grown rapidly owing to its widespread application in science and industry. The aim of the work reported was the green synthesis and chemical characterization of silver nanoparticles from aqueous extract of Falcaria vulgaris leaves (AgNPs@Falcaria) and evaluation of their cytotoxicity and antioxidant, antibacterial, antifungal and cutaneous wound healing effects under in vitro and in vivo conditions. These nanoparticles were characterized using Fourier transform infrared and UV–visible spectroscopies, scanning and transmission electron microscopies and atomic force microscopy. 2,2‐Diphenyl‐1‐picrylhydrazyl free radical scavenging experiments were conducted to evaluate the antioxidant potential, which indicated similar antioxidant potentials for AgNPs@Falcaria and butylated hydroxytoluene. The synthesized AgNPs@Falcaria had great cell viability dose‐dependently, indicating their non‐toxicity. Minimum inhibitory, minimum bactericidal and minimum fungicidal concentrations were determined by macro‐broth dilution assay. The data were analysed using SPSS software (Duncan post hoc test). AgNPs@Falcaria revealed higher antibacterial and antifungal activities than many standard antibiotics (p ≤ 0.01). Also, AgNPs@Falcaria prevented the growth of all bacteria at 2–8 mg ml^?1 concentrations and removed them at 4–16 mg ml^?1 concentrations (p ≤ 0.01). AgNPs@Falcaria inhibited the growth of all fungi at 2–4 mg ml^?1 concentrations and destroyed them at 4–8 mg ml^?1 concentrations (p ≤ 0.01). For in vivo experiments, after creating a cutaneous wound, rats were randomly divided into six groups: untreated control, treatment with eucerin basal ointment, treatment with 3% tetracycline ointment, treatment with 0.2% AgNO₃ ointment, treatment with 0.2% F. vulgaris ointment and treatment with 0.2% AgNPs@Falcaria ointment. Use of AgNPs@Falcaria ointment in the treatment groups substantially decreased (p ≤ 0.01) the wound area, total cells, neutrophils and lymphocytes and markedly raised (p ≤ 0.01) wound contracture, hydroxyproline, hexosamine, hexuronic acid, fibrocytes and fibrocyte/fibroblast ratio compared to the other groups. In summary, the synthesized AgNPs@Falcaria revealed non‐cytotoxicity and antioxidant, antibacterial, antifungal and cutaneous wound healing activities in a dose‐dependent manner.     

Mono-dispersed cross-linked polystyrene micro-spheres prepared by seed swelling polymerization method

A two-step swelling procedure was adopted to synthesize mono-dispersed and highly cross-linked poly (St-divinylbenzene) particles with PSt micro-spheres (1.80 μm in diameter). The PSt micro-spheres were prepared by a dispersion polymerization method and used as seeds. The effects of monomer concentration, ratio of ethanol to water, swelling reagents, crosslinking reagents, swelling temperature and agitation speed on particle size were investigated in detail. The morphologies and size distributions of these micro-spheres were examined by SEM and particle size analysis (PSA). The T _g of the micro-spheres was measured by DSC. The results indicate that the particles (6.20 μm in diameter) exhibit excellent mono dispersed property and high crosslinking degree when the concentration of the swelling reagent was 25%, the concentration of the crosslinking reagents was 23%, the swelling temperature was 30°C and the stirring speed was 150 r/min. __________ Translated from Chinese Journal of Applied Chemistry, 2007, 24(11): 1289–1294     

Design,Synthesis and Molecular Modeling of Nonsteroidal Anti‐inflammatory Drugs Tagged Substituted 1,2,3‐Triazole Derivatives and Evaluation of Their Biological Activities

A novel series of 1,4‐disubstituted‐1,2,3‐triazole derivatives 3a – l and 5a – i were one‐pot synthesized via CuAAC‐alkyne click chemistry and evaluated for their antibacterial activity against four organisms and screened for their anticancer activity against human colon cancer cell line HT‐29 and human lung cancer cell line HTB‐29. These hybrid molecules structure elucidation has been performed by IR, ¹H‐NMR, ¹³C‐NMR, and mass spectral analysis. Synthesized nonsteroidal anti‐inflammatory drugs‐triazoles evaluated for their antibacterial activities against bacterial microorganisms Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumonia. Final compounds 3i , 3c , and 5b showed magnificent broad spectrum activity against P. aeruginosa, K. pneumonia, E. coli, and S. aureus with zone of inhibition values of 20, 15, 17, and 16 mm, respectively. Among the series of compound, 3j showed the best antibacterial activity against all the strains. Further, the compounds 3i and 5a were more cytotoxic than cisplatin against all tested two human cancer cell lines, with 50.8%, and 52.3% and 73.4% and 75.3% of growth, respectively. The synthesized compounds were tested for kinase inhibitory activity against glycogen synthase kinase‐3 protein kinases, in addition, for cytotoxic activity against two different human cancer cell lines.     

The structure–activity relationship of some hexacoordinated dimethyltin(IV) complexes of fluorinated β‐diketone/β‐diketones and sterically congested heterocyclic β‐diketones

The study was focused on the structure–activity relationship of some newly synthesized hexacoordinated dimethyltin(IV) complexes of fluorinated β‐diketone/β‐diketones and sterically congested heterocyclic β‐diketones. These complexes were screened for their antibacterial activity against a Gram‐negative bacterium (Pseudomonas aeruginosa) and Gram‐positive bacteria (Streptomyces griseus, Staphylococcus aureus, Bacillus subtilis) and the results were compared with those of a standard antibacterial drug. Some of the complexes were also screened for their antifungal activity against various fungi (Aspergillus niger, A. flavus, Trichoderma viride, Fusarium oxysporum) and were found to be active. These new hexacoordinated complexes of dimethyltin(IV) were generated by reactions of dimethyltin(IV) dichloride and sodium salts of fluorinated β‐diketone/β‐diketones and sterically congested heterocyclic β‐diketones in 1:1:1 molar ratio in refluxing dry benzene. Plausible structures of these complexes were suggested with the aid of physicochemical and spectroscopic studies. ¹¹⁹Sn NMR spectral data revealed the presence of a hexacoordinated tin centre in these dimethyltin(IV) complexes. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of fluorinated/non‐fluorinated β‐diketones and side‐chain branching of N‐protected amino acids on the antibacterial potential of new heptacoordinated monobutyltin(IV) complexes

The effect of fluorinated/non‐fluorinated β‐diketones and side‐chain branching of N‐protected amino acids on the antibacterial potential of new heptacoordinated monobutyltin(IV) complexes was investigated. New heptacoordinated monobutyltin(IV) complexes having the general formulae BuSn(A)₂B and BuSnA(B)₂ [where AH = (1,3‐dihydro‐1,3‐dioxo‐α‐(substituted)‐2H ‐isoindole‐2‐acetic acids, N‐protected amino acids), R =  CH(CH₃)CH₂CH₃: A₁H; R =  CH(CH₃)₂: A₂H; and BH = R'COCH₂COR″ (β‐diketones), R′ = R″ =  CH₃: B₁H; R′ =  CH₃, R″ =  C₆H₅: B₂H; R′ =  CF₃, R″ =  C₆H₅: B₃H] were synthesized. Complexes BuSn(A)₂B and BuSnA(B)₂ were generated by the reaction of sodium salts of the ligands AH and BH with BuSnCl₃ in 2:1:1 and 1:2:1 molar ratios, respectively. These newly generated complexes were characterized in physicochemical and spectroscopic studies. These complexes contain heptacoordinated tin centres as revealed by ¹¹⁹Sn NMR chemical shift values. Some of the newly generated complexes and their corresponding ligands were screened for their antibacterial activity to study the structure–activity relationship.