scholarly journals Self-Assembly Properties of Amphiphilic Iron(III) Spin Crossover Complexes in Water and at the Air–Water Interface

2018 ◽  
Vol 4 (4) ◽  
pp. 49 ◽  
Author(s):  
Paulo N. Martinho ◽  
Irina A. Kühne ◽  
Brendan Gildea ◽  
George McKerr ◽  
Barry O’Hagan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Spin Crossover ◽  
Water Soluble ◽  
Water Interface ◽  
Nanoparticle Formation ◽  
Alkyl Chains ◽  
Transmission Electron ◽  
Air Water Interface ◽  
Magnetic Profile

The assembly properties of three known spin crossover iron(III) complexes 1–3, at the air–water interface, are reported. All three complexes are amphiphiles, each bearing a pair of Cn alkyl chains on the polyamino Schiff base sal2trien ligand (n = 6, 12, or 18). Complex 1 is water-soluble but complexes 2 and 3 form Langmuir films, and attempts were made to transfer the film of the C18 complex 3 to a glass surface. The nature of the assembly of more concentrated solutions of 3 in water was investigated by light scattering, cryo-SEM (scanning electron microscopy), and TEM (transmission electron microscopy), all of which indicated nanoparticle formation. Lyophilization of the assembly of complex 3 in water yielded a powder with a markedly different magnetic profile from the powder recovered from the initial synthesis, notably, the spin crossover was almost completely quenched, and the thermal behavior was predominantly low spin, suggesting that nanoparticle formation traps the system in one spin state.

scholarly journals Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles

Soft Matter ◽  
2018 ◽  
Vol 14 (25) ◽  
pp. 5256-5269 ◽  
Author(s):  
H. v. Berlepsch ◽  
B. N. S. Thota ◽  
M. Wyszogrodzka ◽  
S. de Carlo ◽  
R. Haag ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Self Assembly ◽  
Single Component ◽  
Alkyl Chains ◽  
Flexible Spacer ◽  
Head Groups ◽  
Transmission Electron

A series of novel non-ionic amphiphiles with dendritic oligoglycerol head groups and lipophilic/fluorophilic tail segments, comprising single or double tail alkyl chains, C8F17-perfluoro rod segments as well as flexible spacer groups were designed and their supramolecular behavior characterised by cryo-transmission electron microscopy and tomography.

scholarly journals Self-assembly of chiral fluorescent nanoparticles based on water-soluble L-tryptophan derivatives of p-tert-butylthiacalix[4]arene

2017 ◽  
Vol 8 ◽  
pp. 1825-1835 ◽  
Author(s):  
Pavel L Padnya ◽  
Irina A Khripunova ◽  
Olga A Mostovaya ◽  
Timur A Mukhametzyanov ◽  
Vladimir G Evtugyn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Water Soluble ◽  
Fluorescent Nanoparticles ◽  
Spectral Emission ◽  
Chiroptical Properties ◽  
Transmission Electron ◽  
Derivatives Of ◽  
Tryptophan Derivatives ◽  
Positively Charged

New water-soluble tetra-substituted derivatives of p-tert-butylthiacalix[4]arene containing fragments of L-tryptophan in cone and 1,3-alternate conformations were obtained. It was shown that the resulting compounds form stable, positively charged aggregates of 86–134 nm in diameter in water at a concentration of 1 × 10−4 M as confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. It was established that these aggregates are fluorescently active and chiral. A distinctive feature of the compounds is the pronounced dependence of their spectral (emission and chiroptical) properties on the polarity of the solvent and the length of the linker between the macrocyclic and fluorophore parts of the molecule.

scholarly journals Functionalizable Glyconanoparticles for a Versatile Redox Platform

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1162
Author(s):  
Marie Carrière ◽  
Paulo Henrique M. Buzzetti ◽  
Karine Gorgy ◽  
Muhammad Mumtaz ◽  
Christophe Travelet ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Self Assembly ◽  
Surface Density ◽  
Water Soluble ◽  
Amphiphilic Copolymers ◽  
Inclusion Properties ◽  
Transmission Electron ◽  
Microscopy Techniques ◽  
Nanometric Size

A series of new glyconanoparticles (GNPs) was obtained by self-assembly by direct nanoprecipitation of a mixture of two carbohydrate amphiphilic copolymers consisting of polystyrene-block-β-cyclodextrin and polystyrene-block-maltoheptaose with different mass ratios, respectively 0–100, 10–90, 50–50 and 0–100%. Characterizations for all these GNPs were achieved using dynamic light scattering, scanning and transmission electron microscopy techniques, highlighting their spherical morphology and their nanometric size (diameter range 20–40 nm). In addition, by using the inclusion properties of cyclodextrin, these glyconanoparticles were successfully post-functionalized using a water-soluble redox compound, such as anthraquinone sulfonate (AQS) and characterized by cyclic voltammetry. The resulting glyconanoparticles exhibit the classical electroactivity of free AQS in solution. The amount of AQS immobilized by host–guest interactions is proportional to the percentage of polystyrene-block-β-cyclodextrin entering into the composition of GNPs. The modulation of the surface density of the β-cyclodextrin at the shell of the GNPs may constitute an attractive way for the elaboration of different electroactive GNPs and even GNPs modified by biotinylated proteins.

Light‐Triggered, Non‐Centrosymmetric Self‐Assembly of Aqueous Arylazopyrazoles at the Air‐Water Interface and SHG Switching

2020 ◽  
Author(s):  
Nobuo Kimizuka ◽  
Yuki Nagai ◽  
Keita Ishiba ◽  
Ryosuke Yamamoto ◽  
Teppei Yamada ◽  
...  
Keyword(s):  
Self Assembly ◽  
Water Interface ◽  
Air Water Interface

scholarly journals Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures

Soft Matter ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. 3096-3104
Author(s):  
Valeria Castelletto ◽  
Jani Seitsonen ◽  
Janne Ruokolainen ◽  
Ian W. Hamley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Self Assembly ◽  
X Ray ◽  
Cryogenic Transmission Electron Microscopy ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ph Dependent ◽  
Ray Scattering

A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties.

scholarly journals Spin Crossover in Nickel(II) Tetraphenylporphyrinate via Forced Axial Coordination at the Air/Water Interface

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4155
Author(s):  
Alexander V. Shokurov ◽  
Daria S. Kutsybala ◽  
Andrey P. Kroitor ◽  
Alexander A. Dmitrienko ◽  
Alexander G. Martynov ◽  
...  
Keyword(s):  
Spin State ◽  
Spin Crossover ◽  
High Spin State ◽  
Water Interface ◽  
Metal Centers ◽  
Axial Coordination ◽  
Vis Spectroscopy ◽  
Air Water Interface ◽  
Nickel Cation

Coordination-induced spin crossover (CISCO) in nickel(II) porphyrinates is an intriguing phenomenon that is interesting from both fundamental and practical standpoints. However, in most cases, realization of this effect requires extensive synthetic protocols or extreme concentrations of extra-ligands. Herein we show that CISCO effect can be prompted for the commonly available nickel(II) tetraphenylporphyrinate, NiTPP, upon deposition of this complex at the air/water interface together with a ruthenium(II) phthalocyaninate, CRPcRu(pyz)2, bearing two axial pyrazine ligands. The latter was used as a molecular guiderail to align Ni···Ru···Ni metal centers for pyrazine coordination upon lateral compression of the system, which helps bring the two macrocycles closer together and forces the formation of Ni–pyz bonds. The fact of Ni(II) porphyrinate switching from low- to high-spin state upon acquiring additional ligands can be conveniently observed in situ via reflection-absorption UV-vis spectroscopy. The reversible nature of this interaction allows for dissociation of Ni–pyz bonds, and thus, change of nickel cation spin state, upon expansion of the monolayer.

Synthesis and Characterization of Water-Soluble Monolayer-Protected Gold Nanoparticles

2011 ◽  
Vol 415-417 ◽  
pp. 617-620 ◽  
Author(s):  
Yan Su ◽  
Ying Yun Lin ◽  
Yu Li Fu ◽  
Fan Qian ◽  
Xiu Pei Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Gold Nanoparticles ◽  
Average Particle Size ◽  
Water Soluble ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Transmission Electron

Water-soluble gold nanoparticles (AuNPs) were prepared using 2-mercapto-4-methyl-5- thiazoleacetic acid (MMTA) as a stabilizing agent and sodium borohydride (NaBH4) as a reducing agent. The AuNPs product was analyzed by transmission electron microscopy (TEM), UV-vis absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR). The TEM image shows that the particles were well-dispersed and their average particle size is about 5 nm. The UV-vis absorption and FTIR spectra confirm that the MMTA-AuNPs was stabilized by the carboxylate ions present on the surface of the AuNPs.

scholarly journals Nanoparticle interaction with model lung surfactant monolayers

2009 ◽  
Vol 7 (suppl_1) ◽  
Author(s):  
Rakesh Kumar Harishchandra ◽  
Mohammed Saleem ◽  
Hans-Joachim Galla
Keyword(s):  
Surface Properties ◽  
Self Assembly ◽  
Current Knowledge ◽  
Surface Film ◽  
Lung Surfactant ◽  
Hydrophobic Surface ◽  
Surface Pattern ◽  
Lipid Monolayers ◽  
Water Interface ◽  
Air Water Interface

One of the most important functions of the lung surfactant monolayer is to form the first line of defence against inhaled aerosols such as nanoparticles (NPs), which remains largely unexplored. We report here, for the first time, the interaction of polyorganosiloxane NPs (AmorSil20: 22 nm in diameter) with lipid monolayers characteristic of alveolar surfactant. To enable a better understanding, the current knowledge about an established model surface film that mimics the surface properties of the lung is reviewed and major results originating from our group are summarized. The pure lipid components dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol have been used to study the biophysical behaviour of their monolayer films spread at the air–water interface in the presence of NPs. Film balance measurements combined with video-enhanced fluorescence microscopy have been used to investigate the formation of domain structures and the changes in the surface pattern induced by NPs. We are able to show that NPs are incorporated into lipid monolayers with a clear preference for defect structures at the fluid–crystalline interface leading to a considerable monolayer expansion and fluidization. NPs remain at the air–water interface probably by coating themselves with lipids in a self-assembly process, thereby exhibiting hydrophobic surface properties. We also show that the domain structure in lipid layers containing surfactant protein C, which is potentially responsible for the proper functioning of surfactant material, is considerably affected by NPs.

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