Bolaamphiphile Surfactants Research Articles

Lanthanide-Containing Polyoxometalate Crystallized with Bolaamphiphile Surfactants as Inorganic–Organic Hybrid Phosphors

Lanthanide elements such as europium exhibit distinctive emissions due to the transitions of inner-shell 4f electrons. Inorganic materials containing lanthanide elements have been widely used as phosphors in conventional displays. The hybridization of lanthanide ions with organic components enables to control of the material’s shapes and properties and broadens the possibility of lanthanide compounds as inorganic–organic materials. Lanthanide ion-containing polyoxometalate anions (Ln-POM) are a promising category as an inorganic component to design and synthesize inorganic–organic hybrids. Several inorganic–organic Ln-POM systems have been reported by hybridizing with cationic surfactants as luminescent materials. However, single-crystalline ordering has not been achieved in most cases. Here, we report syntheses and structures of inorganic–organic hybrid crystals of lanthanide-based POM and bolaamphiphile surfactants with two hydrophilic heads in one molecule. An emissive decatungstoeuropate ([EuW10O36]9−, EuW10) anion was employed as a lanthanide source. The bolaamphiphile counterparts are 1,8-octamethylenediammonium ([H3N(CH2)8NH3]2+, C8N2) and 1,10-decamethylenediammonium ([H3N(CH2)10NH3]2+, C10N2). Both hybrid crystals of C8N2-EuW10 and C10N2-EuW10 were successfully obtained as single crystals, and their crystal structures were unambiguously determined using X-ray diffraction measurements. The photoluminescence properties of C8N2-EuW10 and C10N2-EuW10 were investigated by means of steady-state and time-resolved spectroscopy. The characteristic emission derived from the EuW10 anion was retained after the hybridization process.

An Inorganic-Organic Hybrid Framework Composed of Polyoxotungstate and Long-Chained Bolaamphiphile.

Surfactants are functional molecules utilized in various situations. The self-assembling property of surfactants enables several molecular arrangements that can be employed to build up nanometer-sized architectures. This is beneficial in the construction of functional inorganic-organic hybrids holding the merits of both inorganic and organic components. Among several surfactants, bolaamphiphile surfactants with two hydrophilic heads are effective, as they have multiple connecting or coordinating sites in one molecule. Here, a functional polyoxotungstate inorganic anion was successfully hybridized with a bolaamphiphile to form single crystals with anisotropic one-dimensional alignment of polyoxotungstate. Keggin-type metatungstate ([H2W12O40]6-, H2W12) was employed as an inorganic anion, and 1,12-dodecamethylenediammonium (C12N2) derived from 1,12-dodecanediamine was combined as an organic counterpart. A simple and general ion-exchange reaction provided a hybrid crystal consisting of H2W12 and C12N2 (C12N2-H2W12). Single crystal X-ray structure analyses revealed a characteristic honeycomb structure in the C12N2-H2W12 hybrid crystal, which is possibly effective for the emergence of conductivity due to the dissociative protons of C12N2.

Electrochemical and Theoretical Study of Corrosion Inhibition on Carbon Steel in 1M HCl Medium by 1,10-Bis(4-Amino-3-Methyl-1,2,4-Triazole-5-Thioyl)Decane

Corrosion inhibition using bolaamphiphile surfactants is related to the ability of these compounds to adsorb on liquid–solid interface. In this work, we have synthesized the 1,10-bis(4-amino-3-methyl-1,2,4-triazole-5-thioyl)decane (DTC10) using a new method developed in our laboratory. The synthesized compounds have been purified and characterized by NMR1H and NMR13C spectroscopy. The inhibiting action of DTC10 toward the corrosion of carbon steel in HCl1M solution was investigated using potentiodynamic and electrochemical impedance spectroscopy. We have shown that this compound acts as very good inhibitor for carbon steel in 1M HCl. The values of the transfer resistance, obtained from impedance plots of carbon steel, increase by increasing inhibitor concentration and reach 92% for 10−3M of DTC10. The effects of temperature and immersion time on the inhibition efficiency have also been studied. The effect of temperature was studied between 298 and 328 K; the activation energy Ea and other thermodynamic parameters were calculated. Donating and anti-donating properties of the studied inhibitor 1,10-bis(4-amino-3-methyl-1,2,4-triazole-5-thioyl)decane (DTC10) were illustrated using nucleophilic P− and electrophilic P+ Parr functions based on the density functional theory (DFT). The computational Monte Carlo (MC) method was performed to study the adsorption behavior of DTC10 onto Fe(111) surface in the solution (presence of H3O+, Cl− and H2O particles) and in the vacuum (absence of H3O+, Cl− and H2O particles). Accordingly, the adsorption of DTC10 on the iron surface (111) is more preferred in the solution than in the vacuum.

Bolaamphiphile-class surfactants as corrosion inhibitor model compounds against acid corrosion of mild steel

As long as several years, an ever-growing focus has been placed on the study of corrosion inhibitors due to their useful role in reducing the dissolution of metals in different corrosive environments. In that sense, and with the aim of inhibiting the corrosion effects of HCl acid on mild steel (MS), two bolaamphiphile surfactants, which are 1,6-bis((1H-benzimidazol-2-thioyl)hexane (BITH), and 1,12-bis((1H-benzimidazol-2-thioyl)dodecane (BITD) have been examined by means of electrochemical techniques, Density Functional Theory (DFT), Molecular Dynamics (MD) simulations and Radial Distribution Function (RDF). The corrosion-inhibiting aspects of two compounds have also been examined with the use of scanning electron microscope (SEM) technique. The inhibitory performance of both compounds is improved by increasing the inhibitor concentration, getting the better one to 303 K, and an optimal concentration of 5 × 10 −4 M. Findings are suggestive that both molecules adsorbed on the surface of MS and created hydrophobic films providing an effective barrier into the surface. The results of PDP tests strongly imply that the studied compounds are acting as mixed-type inhibitors. Their adsorption isotherms are Langmuir type, and primary mechanisms involve both physical and chemical adsorption. The computational study was performed in an attempt to identify factors most associated with anti-corrosive properties of tested compounds. • New bolaamphiphiles compounds show good corrosion inhibition performances for MS in HCl. • Bolaamphiphiles compounds act as mixed inhibitor in 1.0 M HCl. • Surface morphology of mild steel was examined by SEM. • The adsorption process of bolaamphiphiles compounds follows Langmuir isotherm. • The experimental results were supported by DFT, Molecular dynamics and RDF.

Preparation and evaluation of a novel anticancer drug delivery carrier for 5-Fluorouracil using synthetic bola-amphiphile based on lysine as polar heads

A novel bolaamphiphile surfactant N,N′-(dodecane-1, 12-diyl) bis (2,6-diaminohexanamide) (DADL) was designed and synthesized using l-lysine and 1,12-diaminododecane as the hydrophilic and hydrophobic part, respectively. After separation and purification, the structure of the synthetic bolaamphiphile surfactant was verified by FTIR, MS and 1H NMR. The synthetic bolaamphiphile was able to self-assemble to form vesicles. After formulation screening, vesicles loaded with 5-Fluorouracil (5-Fu) were prepared with Tween 60 and DADL by sonication and were examined by dynamic light scattering and transmission electron microscopy. Micro-FTIR was applied to investigate the conformation of the bola molecules within the vesicle membrane. The release profile of the vesicles showed a pH-sensitive and sustained release. No significant toxicity was observed in an in vitro cell viability assay. The antitumor efficacy of the 5-Fu-loaded vesicles on H22 tumor-bearing mice was remarkably high due to the EPR effects. These results show that our novel bolaamphiphile derived from lysine has excellent potential as a pH-sensitive drug carrier.

Synthesis and properties of a novel bolaamphiphile surfactant derived from proline

A novel bolaamphiphile surfactant N,N′-(octane-1,8-diyl)bis(pyrrolidine-2-carboxamide) (DAOP), was designed and synthesized from proline and 1,8-diaminooctane, as the hydrophilic part and hydrophobic part, respectively. After separation and purification, the structures of the synthesized bola surfactants were verified by IR, MS and 1H NMR. The pKa was measured by a titration experiment, the turbidity was determined using a Shimadzu UV-1750 spectrophotometer, and the critical micelle concentration (CMC) values of the synthesized surfactants in water were obtained using the conductivity and fluorescence probe measurements. The synthesized bolaamphiphile surfactants demonstrate the ability of self-assemble to form vesicles that were confirmed with dynamic light scattering and transmission electron microscopy. The results showed that the novel bolaamphiphile surfactant derived from proline might potentially be an excellent carrier for drug delivery.

Interfacial Tension of Unsymmetrical Bolaamphiphile Surfactant in Surfactant/Alkali/Crude Oil Systems

The dynamic interfacial tensions between crude oil from Liaoning Daqing Oil Field of China and solution of unsymmetrical bolaamphiphile surfactants were measured. It was found that the added surfactants are greatly effective in reducing the interfacial tensions and can reduce the tensions of oil/water interface to ultra-low (under 10−2 mN/m) at the low surfactant concentration. Otherwise, different aromatic rings attached in the surfactant molecule play an important role on the surfactant capability in reducing crude oil/water interface. The results show that the surfactants with the larger aromatic ring can obtain the lower interfacial tension for their strong adsorption at crude oil/water interface, which provides further examination of this kind of surfactant in reducing crude oil/water interface.

Bolaamphiphile Surfactants as Nanoparticle Stabilizers: Application to Reversible Aggregation of Gold Nanoparticles

Bolaamphiphiles (i.e., surfactants bearing two polar heads connected by a hydrophobic tail) can very efficiently stabilize gold nanoparticles in water. The length of the hydrophobic tail is a crucial parameter controlling the adsorption of the bolaamphiphiles on the nanoparticles and hence the stability of the final colloids. Furthermore, these surfactants offer the possibility to recover and easily redisperse in water nanoparticles without any change in their aggregation state and properties.

Synthesis of bolaamphiphile surfactants and their inhibitive effect on carbon steel corrosion in hydrochloric acid medium

Corrosion inhibition by surfactant molecules is related to the surfactant's ability to aggregate at interfaces and in solution. In this work some new triazole bolaamphiphiles in the series of 1,n-bis(1,2,4-triazolyl)alkane where n=10, 12 have been synthesized. The purity of surfactants synthesized was checked by rutinary methodologies (IR, 1H NMR, 13C NMR, mass spectra and elemental analysis). The aggregation of 1,n-bis(1,2,4-triazolyl)alkane have been determined by surface tension at the air–HCl 1 M interface. The inhibiting action of these compounds towards the corrosion of carbon steel in 1 M HCl solution was investigated using gravimetric, potentiodynamic and electrochemical impedance spectroscopy measurements. Polarization data indicate that these compounds act as very good cathodic inhibitors for carbon steel in 1 M HCl. The values of the transfer resistance, obtained from impedance plots of carbon steel, increase by increasing product concentration. From all measurements carried out, the variation of the inhibition efficiency versus concentration shows the same trend. The electrochemical study shows that DTC12 is the best inhibitor and its efficiency increases with concentration and the highest value obtained is around 94%.

Highly active disordered extra large pore titanium silicate

A new disordered microporous silica and its titanium silicate analog have been synthesized using a bola-amphiphile surfactant 1,12-diamino dodecane (DADD) as a structure directing agent (SDA). Powder X-ray diffraction, N 2 sorption, 29Si MAS NMR, UV–visible diffuse reflectance, FT-IR spectroscopic tools, and TEM and SEM–EDS were used to characterize this material. Only low angle peak was observed in the XRD for all the samples. TEM images indicated a wormhole-like structure in this material similar to that observed for mesoporous silica HMS, MSU-1, MSU-X, etc. or microporous Si-TMS7. Pore diameter of the micropore estimated from N 2 adsorption isotherms was ≈11.2 Å. Spectroscopic data indicated the incorporation of titanium in the tetrahedral silica network in this material. Three microporous type, Ti-DMS1 titanium silicate samples were synthesized with Si/Ti mole ratios of 24.5, 46.5 and 68.0 in the final solid products. After the removal of the template through calcination this microporous titanium silicate showed an excellent catalytic activity in the ammoximation of bulky ketones using dilute aqueous hydrogen peroxide and aqueous ammonia.

Coating a bola-amphiphile on amorphous iron nanoparticles

A bola-amphiphile surfactant, containing a carboxylic acid at one end of the molecule and a thiol at the other, was bonded to nanoparticles of amorphous iron. The bonding of both functional groups was verified by FTIR and XPS measurements. TPD measurements exhibited three temperatures at which molecules are removed from the surface of the iron nanoparticles. The highest temperature, ca. 360°C, is assigned as the temperature at which molecules bonded simultaneously at both ends are desorbed from the surface.

Assembly of Mesoporous Lamellar Silicas with Hierarchical Particle Architectures

A family of silica molecular sieves with lamellar frameworks and hierarchical structure (denoted MSU-V) was assembled from homogeneous solutions of neutral H2N(CH2)nNH2 bolaamphiphiles (n = 12−22) as the structure directors and tetraethylorthosilicate as the inorganic precursor. Optimal lamellar order was observed for four as-synthesized and calcined (550 °C) mesostructures when they were assembled at the following reaction temperatures (T, °C) and surfactant/silica ratios (R) of T = 25 °C, R = 0.26 (C12); T = 45 °C, R = 0.20 (C16); T = 55 °C, R = 0.15 (C18); T = 55 °C, R = 0.11 (C22). MSU-V silica assembled from the short C12 alkyl chain bolaamphiphile exhibited gallery-confined micropores (1.3 nm), but the derivatives prepared from the longer C16−C22 diamines showed gallery-confined mesopores. As the alkyl chain length of the bolaamphiphile surfactant increased from C16 to C22, the size of the gallery-confined mesopores increased from 2.0 to 2.7 nm. The described synthetic strategy afforded hierarchical...

Synthesis of novel bis (glycosyl) ethers as bolaamphiphile surfactants

We have synthesized new bolaamphiphile carbohydrate derivatives having general structures AO(CH 2) n OB or [AO(CH 2) n ] 2C(OH)R. The hydrophilic heads A and B (identical or different) are d-glucose, d-galactose, xylitol, or their respective protected derivatives, and R is an alkyl chain. The carbohydrate units A and B are condensed in the first step as di- O-isopropylidene derivatives with either α,ω-dibromo- or dimesyl-alkanes in the presence of powdered KOH in 9:1 or 4:1 toluene-Me 2SO. Appropriate choice of either selective or total deprotection of acetal groups and either regioselective esterification or regiospecific etherification allows modulation of either the hydrophilic or the lipophilic character of these new surfactants. The ether junctions between the alkyl chain and carbohydrate moiety proved resistant to severe acid-hydrolytic conditions.