Lipophilic Alkyl Chains Research Articles

The effect of fluorination on the liquid crystal and optical behaviors of amphiphilic cyanostilbene-based mesogens

Three series of amphiphilic mesogens containing a cyanostilbene core with zero, one or two lateral fluorine atoms, which attach one polar glycerol group at one end and three lipophilic alkyl chains at the other end were synthesized by Suzuki coupling and Knoevenagel reactions. The thermodynamics, liquid crystalline and photophysical properties of these amphiphilic mesogens were evaluated by polarized optical microscopy, differential scanning calorimetry, small-angle X-ray diffraction, density functional theory calculation, absorption and emission spectra. The non-fluoro and mono-fluoro amphiphilic mesogens display a mesophase transition from hexagonal columnar phase to three-dimensional micellar cubic phase with Im3¯m lattice by the increase of temperature or the elongation of terminal lipophilic alkyl chains. The bi-fluoro amphiphilic mesogens can only self-organize into hexagonal columnar mesophase. Similar spectral properties and weak solvatochromism in these amphiphilic mesogens are observed attributed to the weak intramolecular charge transfer and weak influence of fluorine atom on the electronic properties in both ground and excited states. In addition, aggregation-induced emission behavior could be achieved in these amphiphilic mesogens due to the twisted molecular configuration. Therefore, complex self-assembly structures and interesting photophysical properties may be altered by varying the degree of fluorination of amphiphilic mesogens, which could promote the application of liquid crystalline materials.

Rational Design of a Double-Locked Photoacoustic Probe for Precise In Vivo Imaging of Cathepsin B in Atherosclerotic Plaques.

Atherosclerotic plaque rupture is a significant cause of acute cardiovascular events such as heart attack and stroke, triggered by the decomposition of fiber caps induced by cysteine cathepsin. However, the accurate measurement of cathepsin B (CTB) activity in plaques is challenging due to the low specificity and insufficient penetration depth of available atherosclerosis-associated cathepsin fluorescent probes, hampering reliable assessment of plaque vulnerability. To address these limitations, we added both lipophilic alkyl chain and hydrophilic CTB substrate to the hemicyanine scaffold to develop a lipid-unlocked CTB responsive probe (L-CRP) that uses lipids and CTB as two keys to unlock photoacoustic (PA) signals for measuring CTB activity in lipophilic environments. Such properties allow L-CRP for the reliable imaging of specific CTB activities in foam cells and atherosclerotic plaques while keeping in silence toward CTB in lipid-deficient environments, such as M1-type macrophages and LPS-induced inflammatory lesions. Moreover, the activatable PA signals of L-CRP exhibit a deeper tissue penetration ability (>1.0 cm) than current CTB probes based on near-infrared fluorescent imaging (∼0.3 cm), suitable for atherosclerosis imaging in living mice. In atherosclerotic mice, L-CRP dynamically reports intraplaque CTB levels, which is well-correlated with the plaque vulnerability characteristics such as fiber cap thickness, macrophage recruitment, and necrotic core size, thus enabling risk stratification of atherosclerotic mice complicated with pneumonia. Moreover, L-CRP successfully identifies atherosclerotic plaques in excised human artery tissues, promising for auxiliary diagnosis of plaque vulnerability in clinical application.

Design and Synthesis of New Sulfonic Acid Functionalized Ionic Liquids as Catalysts for Esterification of Fatty Acids with Bioethanol.

In this study, three types of sulfonic acid group functionalized ionic liquids (SAILs) with a different number of catalytic groups and lipophilicity were synthesized and characterized by FT-IR, NMR, and MS analyses. Their catalytic activities were studied in a model esterification of oleic acid with ethanol; heating in a microwave reactor was also used. The experimental results indicated that SAIL, with the lipophilic alkyl chain, performed the best due to its increased solubility in the reaction mixture. Microwave heating was found to be more effective than conventional heating. Recycling experiments show that these novel SAILs can be reused without significant loss of the catalytic activity.

The effect of alkylation degree in hyperbranched polyester on modified heavy oil fluidity

As flow improvers (FIs) for Xinjiang heavy oil with a high content of resins, a series of hyperbranched polyesters with varying degrees of alkylation (FI-1 to FI-7) were synthesized from poly (propylene glycol) (PPG) with trimesic acid (TA) and different dosages of nonanoic acid (NA). Here, the effect of alkylation degree in the flow improver on modified heavy oil fluidity was investigated. Firstly, the evaluation test indicated that the performance of FI-3 was optimal with an appropriate dosage of alkylation modifier, and a rate of viscosity reduction of 56.16%. Supportingly, the chemical structures of three flow improvers with different alkylation degree were compared by Fourier transform infrared spectroscopy (FTIR) and 1H-nuclear magnetic resonance spectra (1HMR). Importantly, the results of Ultraviolet visible spectrophotometer (UV–Vis) showed that FI-3 with an appropriate alkylation degree can better promote the solubility of resins in toluene. The results of simulating studies expounded that the interaction of FI-3 and resin clusters was more sufficient, which made the aggregation degree of resin clusters lower. The results of scanning electron microscope (SEM), white-light interferometer and X-ray diffraction spectra (XRD) revealed that flow improvers can significantly impact the structure of resins. Collectively, this study make known that this type of hyperbranched polyesters with alkylated branched chains can inhibit the aggregation of resins to modified heavy oil fluidity. An appropriate alkylation degree could improve the performance by strengthening the synergistic effect of polar groups and lipophilic alkyl chains. This work has important implications for comprehending the interaction between amphiphile and heavy oil, which could be exploitable for modified polymers used as flow improvers.

Emerging specific selectivity towards mercury(II) cations in water through supramolecular assembly at interfaces

This work deals with the development of ultra-thin film nanosensors for selective and sensitive detection of toxic Hg2+ cations in aqueous media. 1,8-Bis[(2-aminoethyl)amino]anthraquinone D0 was functionalized by alkoxy groups of different length to prepare ligands D3 and D12 with linear arrangement of two polyamine receptors and two lipophilic alkyl chains. Chemosensor D0 only binds copper(II) and mercury(II) cations in water/methanol (1:1 v/v) solutions with no interference by other metal cations. The introduction of alkoxy groups to the anthraquinone scaffold, which are required to form Langmuir monolayers and ultra-thin films on solid supports, does not change the sensing properties of the anthraquinone D0. In contrast to systems without specific molecular order (i.e. solutions and drop-cast films), Langmuir monolayers and ultra-thin Langmuir-Blodgett films of alkoxy-substituted ligands selectively bind only mercury(II) cations, even in the presence of copper(II) ions and 10 other interfering cations. Selective binding of mercury(II) cations was confirmed by the UV–vis absorption and X-ray fluorescence spectroscopies. Thus, ultra-thin films, in which chemosensor molecules are assembled in highly ordered supramolecular systems, display a higher selectivity as compared to that of disordered molecular systems. Ultra-thin sensory film allows for the selective detection of the Hg2+ions in water when their concentration is exceeded 0.01 μM, which corresponds to the action level for Hg2+ ions in drinking water recommended by the U.S. Environmental Protection Agency. Chemosensor D12 is also suitable for the fabrication of electrochemical sensors for mercury(II) cations that show similar sensitivity.

Amphiphilic α-cyanostilbene mesogens with oligooxyethylene polar tails: syntheses and properties

ABSTRACT A series of amphiphilic rodlike α-cyanostilbene mesogens bearing an α-cyanostilbene core, with one/three lipophilic and flexible alkyl chains at one end and a polar oligooxyethylene (EO) at the opposite end, have been synthesized and investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), X-ray scattering, scanning electron microscope (SEM), UV-vis spectroscopy and photoluminescence as well as CV measurements. These compounds can self-assemble into photoresponsive liquid crystalline phases and possess AIEE characteristics, mechanofluorochromic properties and Fe3+ recognition properties. The conductivity of the lithium cation complex was also measured to be 2.6 × 10−7 S m−1. Such compounds can be considered as a kind of multifunctional materials.

Self-assembly and phosphorescence of ionic<italic> </italic>Pd(II) <italic>N</italic>-heterocyclic allenylidene complexes in nonpolar solvents

<p indent=0mm>In sharp contrast with the rich phosphorescent Pt(II) complexes reported in the literatures, phosphorescent Pd(II) complexes in room temperature solutions are scarce, in spite of having the same d⁸ electronic configuration and square-planar coordination mode. Due to their low-lying d-d transition state, phosphorescence origin of the Pd(II) complexes are usually ligand-based, rather than much metal participation. Recently, it has been proved to be an effective strategy to construct self-assembled aggregates via metallophilic Pd···Pd interactions for Pd(II) complexes to achieve metal-metal-to-ligand charge transfer (MMLCT) and corresponding phosphorescent emission in room temperature fluid state. Herein, a cationic <italic>N</italic>-heterocyclic allenylidene (NHA) Pd(II) complex <bold>3</bold>·PF₆ has been synthesized via a facile two-step transmetalation reaction of NHA precursor 2-ethynyl-1,3-dimethyl-1H-imidazol-3-ium hexafluorophosphate (<bold>1</bold>·PF₆) and a pincer type [(C^N^N)PdCl] (HC^N^N = 6-phenyl-4-(3,4,5-tris(dodecyloxy)phenyl)-2,2′-bipyridine) <bold>2</bold> with long alkyl chains in the presence of excessive amount of Ag₂O. It is stable towards air, moisture and common organic solvents. The purity of the cationic NHA Pd(II) complex <bold>3</bold>·PF₆ was characterized via NMR, HR-MS. And IR spectra revealed its resonance structure between zwitterionic acetylide and <italic>N</italic>-heterocyclic allenylidene to some extent. Solid state complex <bold>3</bold>·PF₆ showed orange emission with microsecond lifetime at both room temperature and <sc>77 K.</sc> Temperature-dependent PXRD and TGA/DSC analysis demonstrated the changes of complex <bold>3</bold>·PF₆ from an amorphous phase to a stable crystalline one upon raising the temperature. Due to the lipophilic property of the long alkyl chains, ionic complex <bold>3</bold>·PF₆ can be soluble in both polar (such as dimethyl sulfoxide (DMSO), CH₃CN, and dichloromethane) and nonpolar (such as cyclohexane, methylcyclohexane, and decalin) organic solvent, despite its ionic nature. Complex <bold>3</bold>·PF₆ in degassed dilute DCM solution showed rather weak photoluminescence with peak maximum at <sc>562 nm</sc> (QY < 1%, <italic>τ</italic>: <sc>17 ns).</sc> By increasing the volumetric ratio of cyclohexane which lowered solvent polarity, UV-vis absorption spectra of <bold>3</bold>·PF₆ in mixed solvent of DCM/cyclohexane showed a distinct low-energy absorption band with peak maximum at approximately <sc>500 nm,</sc> and the corresponding phosphorescence emerged. The NMR spectra recorded in mixed solvent deuterium substituted DCM/cyclohexane also showed shifted ¹H chemical-shift and broaden peaks by increasing the volumetric ratio of cyclohexane, which revealed the deeper degree of aggregation of <bold>3</bold>·PF₆ by decreasing the solvent polarity. Meanwhile, enhancement of red-shifted photoluminescence reached its largest absolute QY of 35.4% with emission peak maximum at <sc>612 nm</sc> and lifetime of <sc>730 ns</sc> in pure cyclohexane. The photophysical data recorded for <bold>3</bold>·PF₆ aggregates in other nonpolar solvents (such as toluene and decalin) showed similar broad and featureless phosphorescent emission band with peak maximum at around <sc>620 nm.</sc> The origin of the phosphorescence for <bold>3</bold>·PF₆ aggregates in nonpolar solvents can be ascribed to MMLCT enabled by the metallophilic Pd···Pd interactions. To further explore the self-assembly mode of <bold>3</bold>·PF₆ in nonpolar solvents, the corresponding temperature-dependent UV-vis absorption spectra have been recorded. The distinct low-energy absorption bands represented the aggregation degrees of the <bold>3</bold>·PF₆ monomer in the fluid state. The plot of variable-temperature UV-vis absorbance at the distinct low-energy band (peak maximum at <sc>504 nm)</sc> against temperature well-fits the nucleation-elongation model for the self-assembly of <bold>3</bold>·PF₆ in nonpolar solvent (such as methylcyclohexane and decalin). In conclusion, we have synthesized an ionic Pd(II) <italic>N</italic>-heterocyclic allenylidene complex with lipophilic long alkyl chains and manipulated its self-assembly behavior in nonpolar solvents by controlling the polarity and temperature. Corresponding MMLCT phosphorescence was also recorded and correlated with metallophilic Pd···Pd interactions in the aggregates.

2-O-Monoalkyl isosorbide ethers with C8, C10, C12 and C14 chain lengths.

The title compounds, 6-(octyloxy)hexa-hydro-furo[3,2-b]furan-3-ol, C14H26O4, 6-(decyl-oxy)hexa-hydro-furo[3,2-b]furan-3-ol, C16H30O4, 6-(do-decyl-oxy)hexa-hydro-furo[3,2-b]furan-3-ol, C18H34O4, and 6-(tetra-decyl-oxy)hexa-hydro-furo[3,2-b]furan-3-ol, C20H38O4, consist of a polar headgroup (isosorbide) and a lipophilic alkyl chain linked via an ether bridge. Isosorbide is a biobased diol, containing two fused furan rings. One inter-molecular hydrogen bond connects the mol-ecules between the free endo hy-droxy group and the opposing ether oxygen of the V-shaped head group. Thus the mol-ecule layers inter-lock like in a herringbone pattern parallel to the bc plane.

Thermal cracking of jet propellant-10 with the addition of a core-shell macroinitiator

To accelerate the thermal cracking of hydrocarbon fuels and improve the cooling capacity for aircraft heat exchangers, cetyl-hyperbranched polyethyleneimine (CHPEI) synthesized from the modification of hyperbranched polyethyleneimine (HPEI) with a lipophilic alkyl chain was used as a novel macroinitiator. The pyrolysis performances under supercritical conditions (4.0 MPa, and 600–700 °C) of Jet propellant-10 (JP-10 or exo-tricyclo[5.2.1.02.6]decane) with CHPEI and the monomer triethylamine were compared in an electrically heated alloy tube. Both types of initiators with C-N bonds can promote the thermal cracking of JP-10, while CHPEI with a large molecular weight shows a similar crack-promoting effect to that of triethylamine with adding only one-tenth of the amount of the latter. As a typical example, the addition of 0.20 wt% CHPEI increased the conversion rate of JP-10 from 16.4% to 33.9%, and the corresponding heat sink was improved from 1.96 MJ/kg to 2.18 MJ/kg at 675 °C. On the basis of investigations on the intermediate species from different decomposition pathways of JP-10, it is proved that CHPEI accelerates the thermal cracking of JP-10 by generating lots of free radicals to participate in the H-abstraction reaction of JP-10. These efforts demonstrate that the macroinitiator CHPEI displays a great promise in hydrocarbon fuels for hypersonic applications.

Synthesis and antibacterial bioactivities of cationic deacetyl linezolid amphiphiles

Bacterial infections cause various life-threatening diseases and have become a serious public health problem due to the emergence of drug-resistant strains. Thus, novel antibiotics with excellent antibacterial activity and low cytotoxicity are urgently needed. Here, three series of novel cationic deacetyl linezolid amphiphiles bearing one lipophilic alkyl chain and one non-peptidic amide bond were synthesized and tested for antimicrobial activities. Several compounds showed excellent antibacterial activity toward drug-sensitive bacteria such as gram-negative bacteria Escherichia coli (E. coli), Salmonella enterica (S. enterica) and gram-positive Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis). Moreover, these amphiphilic molecules also exhibited strong activity against drug-resistant species such as methicillin-resistant S. aureus (MRSA), KPC (Klebsiella pneumoniae carbapenemase) and NDM-1 (New Delhi metallo-β-lactamase 1) producing carbapenem-resistant Enterobacteriaceae (CRE). For example, the MICs (minimum inhibitory concentrations) of the best compound 6e, ranged from 2 to 16 μg/mL and linezolid ranged from 2 to >64 μg/mL against these strains. Therefore, 6e is a broad-spectrum antimicrobial compound that may be a suitable lead as an antibiotic. The molecule 6e were found to function primarily by permeabilization and depolarization of bacterial membranes. Importantly, bacterial resistance against compound 6e was difficult to induce, and 6e was stable under plasma conditions and showed suitable activity in mammalian plasma. Thus, these compounds can be further developed into a potential new class of broad-spectrum antibiotics.

Synthesis, Antimicrobial Effect and Surface Properties of Hydroxymethylsubstituted Pyridinium Salts

Background: The cationic surfactants are a huge group of compounds with thousands of applications. Quaternary Ammonium Salts (QAS) make up the majority of this group. Their countless applications in chemistry, the food industry and textile industry are indubitable. The antibacterial and antifungal effect of the various novel QAS is usually referred to in comparison with commercially used benzalkonium and pyridinium salts, since such compounds have found widespread use as common disinfectants e.g. in hospitals as prevention against nosocomial infections. Methods: Three series of N-alkylpyridinium salts with a hydroxymethyl group in positions 2, 3 and 4 were synthesized as novel potential antimicrobial agents. The nucleophilic substitution-type reaction has been used. The novel compounds have been tested as a disinfection agents against bacteria and fungi. The microdilution broth method was utilized for antimicrobial evaluation. Conductivity measurement method has been used for the determination of Critical Micelle Concentration (CMC). Standard MTT test was used for cytotoxic evaluation. Results: We have prepared 15 new compounds based on hydroxymethylpyridine in different positions (2, 3, 4) and the different length of lipophilic alkyl chain on the quaternary nitrogen (C10-18). The compounds were characterized with analytical data (NMR, HRMS) and tested for in vitro antimicrobial activity. The highest, and submicromolar antimicrobial activity was achieved for the 3- hydroxymethylpyridinium salts substituted with longer alkyl chains (C14, C16 and C18). Nhexadecyl- 3-hydroxymethylpyridinium bromide (10b) showed even better performance than standard benzalkonium salts. Conductometric analysis confirmed the trend of decreasing CMC with elongation of the alkyl side chain. Generally, the location of the hydroxymethyl function on the pyridinium scaffold induced only negligible changes in antimicrobial efficacy. Finally, potential use of the N-alkylhydroxymethylpyridinium salts in practice was supported by MMT tests which proved relatively low cytotoxicity of the compounds. Conclusion: We have designed, synthesized and characterized three series of cationic surfactants based on 2-, 3- and 4-hydroxymethylpyridine. The cationic surfactants differ in the length of alkyl side-chain (C10, C12, C14, C16, C18). The antimicrobial effect was evaluated against four groups of microorganisms (gram- positive and gram-negative bacteria, yeasts, and filamentous fungi). The Critical Micelle Concentrations (CMC) were measured by conductivity method, and finally cytotoxicity tests were performed. Keywords: Hydroxymethylpyridinium salts, antimicrobial activity, synthesis, quaternary ammonium salts, critical micelle concentration, conductivity, cytotoxicity.

Novel rGO-T-C(n) Nanosheets developed via click chemistry as a lubricant anti-wear additive

Process equipment and facilities are constantly facing the dilemmas of tear and wear. This manuscript introducing functionalized reduced graphene oxide with triazole moiety via click chemistry as a anti-wear additive. While this has been achieved successfully, full characterization of the new anti-wear additive material revealed it to be promising in ameliorating issues of wears. One of the merits of the synthesized material includes reduction of contact asperity as the lipophilic alkyl chain length increases. It has been tested to be functional when formulated as an additive in group III petroleum base oil. Accordingly, it shows an irregularity in renewable base oil. Following screening evaluations of the lipophilic alkyl chain lengths, the additive with twelve carbon atoms; functionalized reduced graphene oxide, rGO-T-C(12) was confirmed to stand out among others with the good reduction of friction coefficient and the least wear scar diameter of ~539.78 µm, compared to the base oil containing no additive.

Novel Series of Quaternary Ammonium Surfactants Based on 2,3-Dihydro- [1,4]dioxino[2,3-b]pyridin-7-ol Ring: Synthesis, Analysis and Antimicrobial Evaluation

Background: The quaternary ammonium compounds (QAC) are the important group of chemical individuals with widespread usage in many fields of industry or science. The surface-active cationic surfactants are well known disinfection agents. Its effectivity against gram-positive, gramnegative bacteria, yeasts and some viruses is already used in many preparations. On the other hand, the emergence of resistance is the cause of an increasing necessity of new substances. Methods: The series of 5-alkyl-7-hydroxy-2,3-dihydro-[1,4]dioxino[2,3-b]pyridin-5-ium bromides has been synthesized as a novel potential antimicrobial agent. Reaction of the nucleophilic substitution type has been used. The novel compounds have been tested as disinfection agents against bacteria and fungi. The microdilution broth method was utilized for antimicrobial evaluation. Standard MTT test was used for cytotoxic evaluation. Results: We have prepared 5 new compounds based on 2,3-dihydro-[1,4]dioxino[2,3-b]pyridin-7-ol with different length of lipophilic alkyl chain on the quaternary nitrogen (C10-18). The compounds were characterized with analytical data (NMR, HRMS) and evaluated as wide spectrum antimicrobial agents against pathogenic fungal and bacterial strains. We have observed the efficacy towards microbial cells of C12 and C14 compounds for only several antimicrobial strains (Staphylococcus aureus, Candida krusei, Candida glabrata, Trichophyton mentagrophytes). Conclusion: We report on the preparation and characterization of a set of novel cationic surfactant-like compounds based on 2,3-dihydro-[1,4]dioxino[2,3-b]pyridin-7-ol. The novel compounds have been evaluated as wide spectrum antimicrobial agents against pathogenic fungal and bacterial strains. Only two compounds with alkyl chain C12 and C14 showed significant activity against microbes. So, these two compounds should be considered as the potential disinfectants with the selective effect against certain bacterial and fungal strains, not as wide spectra antimicrobial agents. Keywords: Cationic surfactants, quaternary ammonium compounds, synthesis, antimicrobial activity, disinfectants, fungal strain.

Synthesis and bioactivities study of new antibacterial peptide mimics: The dialkyl cationic amphiphiles

The emergence of infectious diseases caused by pathogenic bacteria is widespread. Therefore, it is urgently required to enhance the development of novel antimicrobial agents with high antibacterial activity and low cytotoxicity. A series of novel dialkyl cationic amphiphiles bearing two identical length lipophilic alkyl chains and one non-peptidic amide bond were synthesized and tested for antimicrobial activities against both Gram-positive and Gram-negative bacteria. Particular compounds synthesized showed excellent antibacterial activity toward drug-sensitive bacteria such as S. aureus, E. faecalis, E. coli and S. enterica, and clinical isolates of drug-resistant species such as methicillin-resistant S. aureus (MRSA), KPC-producing and NDM-1-producing carbapenem-resistant Enterobacteriaceae (CRE). For example, the MIC values of the best compound 4g ranged from 0.5 to 2 μg/mL against all these strains. Moreover, these small molecules acted rapidly as bactericidal agents, and functioned primarily by permeabilization and depolarization of bacterial membranes. Importantly, these compounds were difficult to induce bacterial resistance and can potentially combat drug-resistant bacteria. Thus, these compounds can be developed into a new class of antibacterial peptide mimics against Gram-positive and Gram-negative bacteria, including drug-resistant bacterial strains.

Synthesis, liquid-crystalline, photophysical and chemosensor properties of oxadiazole/thiadiazole-based amphiphiles with glycerol groups

Two series of heterocycle-based mesogens consisting of a long 2,5-diphenyl-1,3,4-oxadiazole/thiadiazole rigid core with three lipophilic and flexible alkyl chains at one end and a polar glycerol group at the opposite end have been synthesized via one pot cyclization reaction. These compounds were investigated by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), X-ray scattering, cyclic voltammetry, UV–vis spectroscopy and photoluminescence measurements. Upon elongation of the alkyl chains, a transition from hexagonal columnar phase to Pm3¯n-type cubic phase was observed in both series. Oxadiazole series are blue luminescent LCs with binding selectivity to Li+, while thiadiazole series are blue-green luminescent LCs with binding selectivity to Fe3+.

Self-assembly, AIEE and mechanochromic properties of amphiphilic α-cyanostilbene derivatives

A series of amphiphilic α-cyanostilbene derivatives consisting of an α-cyanostilbene rodlike core with lipophilic and flexible alkyl chains at one end and a polar glycerol group at the opposite end have been synthesized and investigated by polarizing microscopy, DSC, X-ray scattering, SEM, UV-vis spectroscopy and photoluminescence measurements. These compounds can self-assemble into liquid crystalline phase sequence of SmA- Colhex/p6mm- CubI/Pm3¯n in the bulk states and multistimuli responsive organogels in organic solvents. They have reversible photoresponsive properties in solution, liquid crystalline state and gel state. They also show aggregation-induced enhanced emission (AIEE) property, meanwhile, they present excellent mechanochromic behavior and have a good reversibility of fluorescence conversion upon grinding-fuming process.

Inclusion Complexes of a New Family of Non-Ionic Amphiphilic Dendrocalix[4]arene and Poorly Water-Soluble Drugs Naproxen and Ibuprofen.

The inclusion complexes of a new family of nonionic amphiphilic calix[4]arenes with the anti-inflammatory hydrophobic drugs naproxen (NAP) and ibuprofen (IBP) were investigated. The effects of the alkyl chain’s length and the inner core of calix[4]arenes on the interaction of the two drugs with the calix[4]arenes were explored. The inclusion complexes of Amphiphiles 1a–c with NAP and IBP increased the solubility of these drugs in aqueous media. The interaction of 1a–c with the drugs in aqueous media was investigated through fluorescence, molecular modeling, and 1H-NMR analysis. TEM studies further supported the formation of inclusion complexes. The length of lipophilic alkyl chains and the intrinsic cyclic nature of cailx[4]arene derivatives 1a–c were found to have a significant impact on the solubility of NAP and IBP in pure water.

Molecular aggregation of naphthalimide organic semiconductors assisted by amphiphilic and lipophilic interactions: a joint theoretical and experimental study.

Amphiphilic and lipophilic donor-acceptor naphthalimide-oligothiophene assemblies exhibiting almost identical intramolecular properties, but differing in their intermolecular interactions, have been synthesized. Here we analyze the effect of replacing the normally used lipophilic alkyl chains with hydrophilic ones in directing molecular aggregation from an antiparallel to a parallel stacking. This different molecular packing of the amphiphilic, NIP-3TAmphi, and lipophilic, NIP-3TLipo, systems is assessed by electronic spectroscopies, scanning electronic microscopy and DFT quantum-chemical calculations. Theoretical calculations indicate that the presence of amphiphilic interactions promotes a face-to-face parallel arrangement of neighbor molecules, which induces improved electronic coupling and therefore enhances the charge transport ability and photoconducting properties of this type of materials. Time of flight and photoconducting measurements are used to determine the impact of the amphiphilic and lipophilic interactions on their possible performance in optoelectronic devices.

Optical Limiting Properties of Graphene/Polymer Composites.

Graphene oxide (GO) was doped into four polymers films: Poly(methyl methacrylate) (PMMA), polystyrene (PS), polycarbonate (PC), and polyacrylonitrile (PAN). Following that, their optical limiting properties were investigated at 532 nm. In order to make GO hydrophobic, the lipophilic alkyl chains were connected to GO. The results showed that GO/PAN composite possesses better non-linear response than the other three composites at the same transmission (T ~ 59%). The reason were attributed to the thermal effect coming from high input fluence of laser, which improved the cross link density of PAN and further enhanced the interaction between the GO-ODA and PAN. Meanwhile, GO/PC and GO/PS had similar optical limiting property and GO/PMMA film gave the weakest optical limiting effect in our experiment.

A theranostic agent for in vivo near-infrared imaging of β-amyloid species and inhibition of β-amyloid aggregation

Amyloid-β (Aβ) peptide as one of the main components of senile plaques is closely related to the onset and progression of incurable Alzheimer's disease (AD). Numerous efforts have been devoted to develop probes for Aβ species/plaque imaging for AD diagnostics and to develop aggregation inhibitors preventing formation of toxic soluble oligomeric Aβ for therapeutics. Herein, for the first time, a series of novel charged molecules, which can simultaneously perform near infra-red in vivo imaging of Aβ species/plaques in animal model and inhibition of self-aggregation of Aβ monomer from forming toxic oligomers, are reported. Among them, DBA-SLOH showed excellent blood-brain barrier (BBB) permeability and biocompatibility due to the incorporation of lipophilic alkyl chains with moderate length into the charged skeleton. Importantly, DBA-SLOH was found to have a high binding affinity toward Aβ species exhibiting a dramatic fluorescence enhancement upon interacting with Aβ species. Despite a weaker binding with Aβ monomers as compared to Aβ aggregates, DBA-SLOH could effectively prevent the Aβ1-40 and Aβ1-42 peptides from self-aggregation and forming toxic oligomers. This multifunctional fluorescent molecule shows promising potential as a theranostic agent for the diagnosis and therapy of AD.