CH2)3N Research Articles

Cationic–anionic fluorinated surfactant mixtures based on short fluorocarbon chains as potential aqueous film-forming foam

A strategy for aqueous film-forming foam (AFFF) using cationic-anionic surfactant mixtures with short fluorocarbon chains (≤C4) in both cationic and anionic surfactants was proposed. The minimum surface tension (γmin) of mixtures of C4F9SO2NH(CH2)3N(CH3)3I (C4FI) and CnF2n+1COONa (n = 1, 2, 3, 4) with different molar ratios (5:1, 2:1, 1:1, 1:2, 1:5) was measured at 25 °C. The γmin for all mixtures of C4FI–CnF2n+1COONa were remarkably lower than that of pure C4FI. Among these mixtures, the equimolar mixture of C4FI–C3F7COONa was chosen because of the low γmin, qualified solubility and relatively high fluorine efficiency. The spreading coefficients of its aqueous solution on n-heptane, toluene, benzene, cyclohexane and gasoline were all positive, indicative of its potential in AFFF. The film spreading, sealability and foaming were also tested. The influences of ‘green’ additives (alkyl glucose amide, xanthan gum and sodium carboxymethylcellulose) on foaming performance were studied, in which small dosage of xanthan gum could greatly retard the drainage of foam. It was confirmed that the mixing of oppositely charged surfactants both possessing short fluorocarbon chains was a valuable thought to design AFFF. In application, the quaternary ammonium surfactant likewise can be bromide or chloride rather than iodide for reasons of cost-reduction and stability.

Inhibition Performance of Amphoteric Fluorinated Surfactant and its Mixed Systems on Carbon Steel in Hydrochloric Acid

AbstractC8F17SO2NH(CH2)3N(CH3)2(CH2COO)Na (PNHD) is a novel amphoteric fluorinated surfactant. The corrosion inhibition of PNHD and its mixed systems with cetyl trimethylammonium bromide (CTAB) or octylphenol ethoxylate 9.5 EO (TX‐10) for carbon steel Q235 in 1.0 M HCl solution was studied in this paper. The corrosion inhibition efficiency (η) was determined by weight loss, electrochemical methods and scanning electron microscope. The values of η from the three methods were almost identical. The hydrophilic head group of PNHD has two lone pairs of electrons at the nitrogen atoms, suggesting a chemisorption mechanism between carbon steel and surfactant. The PNHD and mixed systems inhibitors acted as a mixed inhibitor; there is interaction between PNHD and CTAB or TX‐100. A compact protective film was formed in PNHD and its mixed systems.

Structural evaluation of tandem hairpin pyrrole-imidazole polyamides recognizing human telomeres.

A polyamide containing N-methylpyrrole (Py) and N-methylimidazole (Im), designated PIPA, binds with high affinity and specificity to specific nucleotide sequences in the minor groove of double-helical DNA. Based on a recent report of the synthesis of PIPA for telomere visualization, the present paper focused on the size of the connecting part (hinge region) of two PIPA segments of the tandem hairpin PIPA, Dab(Im-Im-Py)-Py-Py-Py-Im-[Hinge]-Dab(Im-Im-Py)-Py-Py-Py-Im-βAla-NH(CH2)3N(CH3)-(CH2)3NH-[Dye]. The present paper also describes the characterization of binding by measuring the thermal melting temperature and surface plasmon resonance and by specific staining of telomeres (TTAGGG)n in human cells. Microheterogeneity was also investigated by high-resolution mass spectrometry. We found that the optimal compound as the hinge segment for telomere staining was [-NH(C2H4O)2(C2H4)CO-] with tetramethylrhodamine as the fluorescent dye.

Production of SBA-15 mesoporous silica containing ammonium groups in the surface layer

The template method (surfactant: Pluronic 123) has been applied to produce mesoporous silica that contain ammonium groups [≡Si(CH2)3NH3]+, [≡Si(CH2)3NH2(CH2)2NH3]2+, [≡Si(CH2)3NH2(CH2)2NH2(CH2)2NH3]3+ and [≡Si(CH2)3N(CH3)3]+ in the surface layer, which has been confirmed both by data of elemental analysis for nitrogen and by IR spectroscopy. Using diffractometry and TEM, it has been demonstrated that the synthesized samples contain a hexagonal structure characteristic of SBA-15 silica. This agrees with the parameters of their porous structure calculated by isotherms of low-temperature adsorption of nitrogen: Ssp = 520–750 m2/g, Vc = 0.6–1.2 cm3/g, and d = 4.9–8.9 nm.

Alkoxy Silanes as External Donors for Polypropylene Procatalyst: Study on Polymerization Performance and Effect on Resin Properties

Effect of alkoxy silane [R1Si(OR2)3] on propylene polymerization was studied by systematic variation of functional groups e.g R2 = CH3, R1 = ‒OCH3, ‒CH3, ‒(CH2)2CH3, ‒(CH2)3N(CH3)2, ‒(CH2)3N(C2H5)2. Increase in bulkiness of alkyl group from ‒OCH3 to ‒(CH2)3N(C2H5)2 leads to decrease in productivity of catalyst with increase in MFI. Kinetics study revealed reduction of Rp0 and increase in decay kinetic constant with increase in bulkiness of functional groups. Morphology study by SEM of polypropylene particles illustrated that resin particle shape (particle circularity, topography and flowability) have been comparative. Polypropylene particle size distribution study revealed shift toward higher particles size regime for bulkier groups.

Antifungal activity of organotin compounds with functionalized carboxylates evaluated by the microdilution bioassayin vitro

We investigated the susceptibility of 96 well-characterized strains of yeast-like and filamentous fungi towards new organotin compounds: (1) [Sn(C4H9)3(OOCC6H4SO3H-2)], (2) Sn(C4H9)3{OOC(CH2)3P(C6H5)3}]Br, and (3) [Sn(C6H5)3[OOC(CH2)3N(CH3)3}]Cl. In the case of yeast-like fungi, the in vitro susceptibility tests were carried out according to the Clinical Laboratory Standards Institute (CLSI, formerly NCCLS) reference method M27-A2, while for filamentous fungi the investigations were conducted according to the M38-A and M38-P methods. The organotin complexes 1, 2 and 3 are active antifungal agents. Minimal inhibitory concentrations (MIC) were in the range of 0.25-4.68 microg/ml for all tested fungal strains. Considerably larger differences were found for minimal fungicidal concentrations (MFC). In the case of yeast-like fungi, the fungicidal effect was generally observed at organotin compounds concentrations of 2.34-9.37 microg/ml. The MFC values for filamentous fungi were considerably higher and were in the range of 18.74-50 microg/ml. In conclusion, organotin compounds 1, 2 and 3 showed high fungistatic and fungicidal activities against different species of pathogenic and nonpathogenic fungi. However, they were also highly cytotoxic towards two mammalian cell lines.

Antifungal activity of organotin compounds with functionalized carboxylates evaluated by the microdilution bioassay in vitro

We investigated the susceptibility of 96 well-characterized strains of yeast-like and filamentous fungi towards new organotin compounds: (1) [Sn(C4H9)3(OOCC6H4SO3H-2)], (2) Sn(C4H9)3{OOC(CH2)3P(C6H5)3}]Br, and (3) [Sn(C6H5)3[OOC(CH2)3N(CH3)3}]Cl. In the case of yeast-like fungi, the in vitro susceptibility tests were carried out according to the Clinical Laboratory Standards Institute (CLSI, formerly NCCLS) reference method M27-A2, while for filamentous fungi the investigations were conducted according to the M38-A and M38-P methods. The organotin complexes 1, 2 and 3 are active antifungal agents. Minimal inhibitory concentrations (MIC) were in the range of 0.25-4.68 microg/ml for all tested fungal strains. Considerably larger differences were found for minimal fungicidal concentrations (MFC). In the case of yeast-like fungi, the fungicidal effect was generally observed at organotin compounds concentrations of 2.34-9.37 microg/ml. The MFC values for filamentous fungi were considerably higher and were in the range of 18.74-50 microg/ml. In conclusion, organotin compounds 1, 2 and 3 showed high fungistatic and fungicidal activities against different species of pathogenic and nonpathogenic fungi. However, they were also highly cytotoxic towards two mammalian cell lines.

A Dawson‐Type Dirhenium(V)‐Oxido‐Bridged Polyoxotungstate: X‐ray Crystal Structure and Hydrogen Evolution from Water Vapor under Visible Light Irradiation

AbstractThe synthesis and crystal structure of a Dawson‐type dirhenium(V)‐oxido‐bridged polyoxotungstate are described. The potassium salt K14[O{ReV(OH)(α2‐P2W17O61)}2]·21H2O (K‐1) was obtained as analytically pure, homogeneous, black‐purple crystals by the reaction of a monolacunary Dawson polyoxotungstate with [ReIVCl6]2– in water, followed by crystallization from an aqueous HCl solution in the dark. Single‐crystal X‐ray structure analysis revealed that the dimeric dirhenium(V)‐oxido‐bridged structure has overall C2h symmetry. Characterization of K‐1 was also accomplished by elemental analysis, TG/DTA, and FTIR, UV/Vis absorption, ESR, and solution 31P NMR spectroscopy. Furthermore, the black‐purple compound K‐1 was grafted onto a TiO2 surface by electrostatic binding to give TiO2 with a cationic quaternaryammonium moiety (1‐grafted TiO2). Elemental analysis of 1‐grafted TiO2 indicated that the seven potassium counterions of K‐1 were ion‐exchanged with seven cationic ammonium moieties to form {TiO2}5500[≡Si(CH2)3N(CH3)3Cl]7[≡Si(CH2)3N+(CH3)3]7(K7[O{Re(OH)(α2‐P2W17O61)}2]7–) and seven molecules of KCl. The diffuse reflectance (DR) UV/Vis spectrum of 1‐grafted TiO2 exhibited two sharp bands at 496 nm and 751 nm due to the ReV→WVI intervalence charge transfer (IVCT) band and the d–d band of the rhenium(V) atom, respectively, in the visible light region, which suggestedthat polyoxoanion 1 was isolated on the TiO2 surface. With 1‐grafted TiO2, hydrogen evolution from water vapor under irradiation with visible light (>400 nm and >420 nm) was achieved. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Morphology of Nanostructured Platinum in Mesoporous MaterialsEffect of Solvent and Intrachannel Surface

An intrachannel surface of host silica was functionalized through the reaction of surface silanol groups with silanes to generate a monolayer of positively charged groups, and together with the strongly adsorbed and negatively charged PtCl6(2-), resulting in nanostructured platinum-mesoporous silica composites. The highly dispersed Pt nanoparticles and nanonetworks are fabricated from (CH3O)3Si(CH2)3N(CH3)3+Cl- functionalized mesoporous silica MCM-48 with H2PtCl6 in ethanol and water solvent, and characterized by PXRD, XAS, TEM, and N2 adsorption. The solvent of H2PtCl6 solution is found to affect the mobility of Pt precursors and the resulting morphology of nanostructured metallic Pt. The effect of the intrachannel surface properties on the incorporation and the morphology of nanostructured Pt on the deposition of Pt(NH3)4Cl2 and H2PtCl6 on Al-doped or C-coated mesoporous silica MCM-41 is also studied relative to that on pure silica MCM-41.

Mitomycin dimers: polyfunctional cross-linkers of DNA.

The three dimers 3, 4, and 5 of mitomycin C (MC), a natural antibiotic and cancer chemotherapeutic agent, were synthesized in which two MC molecules were linked with -(CH(2))(4)-, -(CH(2))(12)-, and -(CH(2))(3)N(CH(3))(CH(2))(3)- tethers, respectively. The dimeric mitomycins were designed to react as polyfunctional DNA alkylators, generating novel types of DNA damage. To test this design, their in vitro DNA alkylating and interstrand cross-linking (ICL) activities were studied in direct comparison with MC, which is itself an ICL agent. Evidence is presented that 3-5 multifunctionally alkylate and cross-link extracellular DNA and form DNA ICLs more efficiently than MC. Reductive activation, required for these activities, is catalyzed by the same reductases and chemical reductants that activate MC. Dimer 5, but not MC, cross-linked DNA under activation by low pH also. Sequence specificities of cross-linking of a 162-bp DNA fragment (tyrT DNA) by MC, 3, and 5 were determined using DPAGE. The dimers and MC cross-linked DNA with the same apparent CpG sequence specificity, but 5 exhibited much greater cross-linking efficacy than MC. Greatly enhanced regioselectivity of cross-linking to G.C rich regions by 5 relative to MC was observed, for which a mechanism unique to dimeric MCs is proposed. Covalent dG adducts of 5 with DNA were isolated and characterized by their UV and mass spectra. Tri- and tetrafunctional DNA adducts of 5 were detected. Although the dimers were generally less cytotoxic than MC, dimer 5 was highly and uniformly cytotoxic to all 60 human tumor cell cultures of the NCI screen. Its cytotoxicity to EMT6 tumor cells was enhanced under hypoxic conditions. These findings together verify the expected features of the MC dimers and warrant further study of the biological effects of dimer 5.

Synthesis and structural characterization of a volatile, intramolecularly coordinated monomeric homoleptic magnesium alkylamide

The design, synthesis and X-ray crystal structure of the first intramolecularly coordinated homoleptic, monomeric and highly volatile magnesium alkylamide example, Mg{N[Si(CH3)3](CH2) 3N(CH3)2}2, are described.

Quantitative analysis of Pc 4 localization in mouse lymphoma (LY-R) cells via double-label confocal fluorescence microscopy.

Photodynamic therapy (PDT) is a novel cancer therapy that uses light-activated drugs (photosensitizers) to destroy tumor tissue. Reactive oxygen species produced during PDT are thought to cause the destruction of tumor tissue. However, the precise mechanism of PDT is not completely understood. To provide insight into the in vitro mechanisms of PDT, we studied the subcellular localization of the photosensitizer HOSiPcOSi(CH3)2-(CH2)3N(CH3)2 (Pc 4) in mouse lymphoma (LY-R) cells using double-label confocal fluorescence microscopy. This technique allowed us to observe the relative distributions of Pc 4 and an organelle-specific dye within the same cell via two, spectrally distinct, fluorescence images. To quantify the localization of Pc 4 within different organelles, linear correlation coefficients from the fluorescence data of Pc 4 and the organelle-specific dyes were calculated. Using this measurement, the subcellular spatial distributions of Pc 4 could be successfully monitored over an 18 h period. At early times (0-1 h) after introduction of Pc 4 to LY-R cells, the dye was found in the mitochondria, lysosomes and Golgi apparatus, as well as other cytoplasmic membranes, but not in the plasma membrane or the nucleus. Over the next 2 h, there was some loss of Pc 4 from the lysosomes as shown by the correlation coefficients. After an additional incubation period of 2 h Pc 4 slowly increased its accumulation in the lysosomes. The highest correlation coefficient (0.65) was for Pc 4 and BODIPY-FL C5 ceramide, which targets the Golgi apparatus, and also binds to other cytoplasmic membranes. The correlation coefficient was also high (0.60) for Pc 4 and a mitochondria-targeting dye (Mitotracker Green FM). Both of these correlation coefficients were higher than that for Pc 4 with the lysosome-targeting dye (Lysotracker Green DND-26). The results suggest that Pc 4 binds preferentially and strongly to mitochondria and Golgi complexes.

Unusual polyamines in aquatic plants: the occurrence of homospermidine, norspermidine, thermospermine, norspermine, aminopropylhomospermidine, bis(aminopropyl)ethanediamine, and methylspermidine

Four aquatic plants were tested for the occurrence of unusual polyamines. The leaves of the aquatic plants tested ubiquitously contained homospermidine in addition to usual polyamines such as diaminopropane, putrescine, cadaverine, spermidine, spermine, and agmatine. Brasenia schreberi and Nuphar japonicum belonging to the family Nymphaeaceae contained aminopropylhomospermidine. Norspermidine and norspermine were detected in the blackweed Hydrilla verticillata belonging to Hydrocharitaceae. Thermospermine was detected in Brasenia schreberi. A novel tetraamine, N,N'-bis(3-aminopropyl)-1,2-ethanediamine (NH2(CH2)3NH(CH2)2NH(CH2)3NH2), was discovered in the aquatic plant Nuphar japonicum. This is the first report of the occurrence of N4-methylspermidine (NH2(CH2)3N(CH3)(CH2)4NH2) in the water chestnut Trapa natas belonging to the family Hydrocaryaceae. Key words: aquatic plants, polyamine, bis(aminopropyl)ethandiamine, methylspermidine.

Structure−Spectroscopy Correlations in Silver Thiolates: Application to the Structure of Silver 1,5-Pentanedithiolate

A variety of spectroscopic methods have been used to deduce the solid-state structure of Ag2[S(CH2)5S] (1), the yellow compound formed by mixing of Ag+ and 1,5-pentanedithiol. Solid-state reflectance UV−vis, X-ray diffraction, cross-polarization magic angle spinning (CPMAS) 13C NMR, and CPMAS 109Ag NMR spectra of 1 were compared to corresponding spectra for two crystallographically-characterized homoleptic Ag thiolates, the cluster Ag5{μ2-S(CH2)3N(CH3)2}3{μ2-S(CH2)3NH(CH3)2}3(ClO4)2 (2) and the infinite strand AgSC(CH2CH3)2CH3 (3). Two limiting geometries for 1 are considered: a linear polymer and a layered geometry similar to that adopted by neutral Ag thiolates with primary, unbranched alkane chains. All spectroscopic data are consistent with the latter structure. Information about alkane chain orientation and Ag−S vibrational modes in 1 was obtained by comparison of low-wavenumber Raman and diffuse reflectance infrared Fourier transform (DRIFT) spectra with those for all-trans AgS(CH2)3CH3 (T) and the C(1)−C(2) gauche isomer (G). The spectra show that the majority of alkane chains in 1 adopt a fully extended, all-trans geometry, but that gauche conformers are clearly present. These experiments demonstrate that sensitive structure elucidation can be achieved by combination of solid-state spectroscopic methods, when appropriate standards are available. Although isostructural layered, neutral compounds of the form AgSR exhibit liquid crystalline behavior upon melting, 1 does not, a consequence of covalent attachment between layers.

Benzimidazo[1,2‐c]quinazoline dimers as potential antitumor agents

AbstractThe 6‐substituted benzimidazo[1,2‐c]quinazoline 1 is a lead structure from our DNA intercalator program and is cytotoxic to the human colon cancer tumor line HT‐29 with an inhibitory concentration 50, IC50 of 4.00 μM. In order to try and improve the limited cytotoxicity of this class of compound we prepared a series consisting of two benzimidazo[1,2‐c]quinazoline moieties linked by a polyalkylamino bridge, of different length and substitution. The compound with the ‐NH‐(CH2)3‐N(CH3)‐(CH2)3‐NH‐bridge had an inhibitory concentration 50, IC50 of 0.5 μM. When tested in vivo, however, no clear anti‐tumor activity was produced in the human breast cancer tumor line MX‐1 or the human melanoma tumor line LOX, human tumor xenografts models.

Stability of Quaternary Ammonium-Functionalized Organosiliconates in Alkaline Hydrolysis

The alkaline hydrolytic stability of quaternary ammonium-functionalized organosiliconate has been studied using 13C NMR. The half-life of (CH3O)3Si(CH2)3N(CH3)3Cl was determined under conditions in which base-catalyzed Si-R bond cleavage occurs. At 200°C, t1/2 decreased by three orders of magnitude from pH 5 to pH 13. The formation of propyltrimethyl ammonium, and its subsequent further hydrolysis to propanol and trimethylamine, was verified by deuterium labeling experiments. The relevance of these findings to the possible use of these reagents in novel materials synthesis is discussed.

Polyethers for biomedical applications. Polymerization of propylene oxide by organozinc/organotin catalysts

AbstractThe polymerization of propylene oxide to obtain a high‐molecular‐weight polymer with an atactic structure required for the application as artificial blood vessels was investigated using combinations of organozinc and organotin compounds as catalyst. The composition of the most active catalyst, resulting from the reaction of diphenyltin sulfide with bis(3‐dimethyl‐aminopropyl)zinc, was found to be R(C6H5)2Sn(SZn)2R with R = (CH2)3N(CH3)2. Using this catalyst, an anionic coordination polymerization was observed with neither stereoselectivity nor living type or cationic features. At low catalyst concentration (0,03 mol‐% Zn) a high‐molecular‐weight poly(propylene oxide) (PPOX) was obtained in 80–90% yield (Mw = 500000; 40% isotactic). Lowering of the catalyst concentration and increasing the polymerization temperature changed the kinetics and the stereochemistry of the polymerization leading to polymers of lower molecular weight and to a decrease in the isotactic PPOX fraction to 20%, probably due to an association of the catalytic species.

Molecular structures of bis[3-(dimethylamino)propyl]zinc, Zn[(CH2)3N(CH3)2]2, by x-ray and gas electron diffraction and bis[3-(methylthio)propyl]zinc, Zn[(CH2)3SCH3]2, by gas electron diffraction

Molecular structures of bis[3-(dimethylamino)propyl]zinc, Zn[(CH2)3N(CH3)2]2, by x-ray and gas electron diffraction and bis[3-(methylthio)propyl]zinc, Zn[(CH2)3SCH3]2, by gas electron diffraction

Biological properties of streptonigrin derivatives. II. Inhibition of reverse transcriptase activity.

Antitumor antibiotic streptonigrin (STN-COOH) is a potent inhibitor of avian myeloblastosis virus (AMV) and human immunodeficiency virus reverse transcriptases. The carboxyl group at 2'-position of STN-COOH was modified to give esters, hydrazide, amides and amino acid derivatives for biological studies. Against AMV reverse transcriptase, the hydrazide, amides and amino acid derivatives showed inhibitory activity, which compared favorably to that of STN-COOH, with the ID50 values ranging 2-8 μg/ml. In contrast, the esters lacked this activity except for those having a dimethylamino group in the substituent. Splenomegaly caused by Friend leukemia virus infection was significantly inhibited by STN-COOH and STN-COO(CH2)3N(CH3)2, but not STN-CONH(CH2)3N(CH3)2. Doxorubicin-resistant murine lymphoblastoma L5178Y cells showed collateral sensitivity to both STN-COOH and STN-COO(CH2)3N(CH3)2 not only in vitro but also in vivo.

Nonquaternary cholinesterase reactivators. Dialkylaminoalkyl thioesters of .alpha.-ketothiohydroximic acids as reactivators of diisopropyl phosphorofluoridate-inhibited acetylcholinesterase

We have prepared a series of alpha-ketothiohydroximic acid thioesters and evaluated them in vitro with respect to their ability to reactivate (diisopropylphosphoryl)acetylcholinesterase. The compounds conform to the general formula RC(=O)C(=NOH)S(CH2)nNR2'.HCl, where R = CH3, C6H5, 4-CH3OC6H4, 4-NO2C6H4; n = 2, 3; and R' = CH3, C2H5, or i-C3h7. We also prepared 4-BrC6H4C(=NOH)S(CH2)2N(C2H5)2.HCl and 4-CH3OC6H4C(=O)C(=NOH)S(CH2)2N(C2H5)2.CH3I for comparison. The alpha-ketothiohydroximates exhibit oxime acid dissociation constants (pKa) in the range 6.9 to 8.4, bracketing the value of pKa = 7.9, believed to be optimal for acetylcholinesterase reactivation. The compounds are also good nucleophiles; bimolecular rate constants (kn) for reaction with p-nitrophenyl acetate follow the expression log (kn) = 6.7 - 0.69(14 - pKa = The reactivation of (diisopropylphosphoryl)acetylcholinesterase is highly dependent on the alpha-ketothiohydroximate structure: 4-h incubation of inhibited enzyme at pH 7.6, 25 degrees C, with 1 x 10(-3) M 4-CH3OC6H4C(=O)C(=NOH)S(CH2)3N(CH3)2.HCl gives no detectable restoration of activity, whereas 4-CH3OC6H4C(=O)C(=NOH)S(CH2)2N(C2H5)2.HCl restores inhibited enzyme activity to 58% of control under identical conditions. With alpha-ketothiohydroximate in excess over inhibited enzyme, the kinetics of reactivation are governed by an equilibrium constant (Kr) for binding alpha-ketothiohydroximate to the inhibited enzyme and a nucleophilic displacement rate constant (kr) for attack on phosphorus.