Metallogel of bis(tetrazole)-appended pyridine derivative with CoBr₂ as a chemoprobe for volatile gases containing chloride atom

<p>A bis(tetrazole)-appended ligand <b>1</b> formed the metallogel efficiently by mixing with Co²⁺ ion. Interestingly, the metallogel <b>1</b> with CoBr₂ showed the orange yellow colour, which has octahedral structure. The rheological properties of metallogel obtained with CoBr₂ were ca. 1.5-fold larger than that for the metallogel obtained with CoCl₂. Upon addition of HCl, SOCl₂, (COCl)₂ and COCl₂ containing chloride atoms in the metallogel <b>1</b> prepared with CoBr₂ changed from orange yellow to blue-green colour. These results indicate that the octahedral structure of metallogel was converted into the tetrahedral structure. On the other hand, no significant colour changes were observed in the presence of an excess of other anions, namely HF, HBr, HI, HNO₃ and H₂SO₄. These findings indicate that the metallogel <b>1</b> with CoBr₂ is useful as a chemoprobe for gases containing chloride atom.</p

Different Origins of Strain-Induced Chirality Inversion of Co²⁺-Triggered Supramolecular Peptide Polymers

We report a distinctly different dynamic helix inversion pathway of self-assembled terpyridine-based ligands composed of different numbers of peptide moieties with Co²⁺ and its amplification of strain-induced chirality from an achiral terpyridine moiety. The helical chirality of the metal centers, coordinated by terpyridine ligands, is controlled by strain-induced chirality with complex ligand-to-Co²⁺ ratios. We also show that the distinct helical inversion mechanism is significantly dependent on the number of peptides attached to ligands. The helical inversion pathway of the self-assembled ligand (<b>R-1</b> and <b>S-1</b>) complexes composed of one alanine analogue (<i>R</i>- or <i>S</i>-2-amino-1-propyl moiety) and one long saturated alkyl chain relies on two steps of chirality with different complex geometries, first from strain-induced chirality originating from an octahedral structure to octahedral structure with different helical direction and then on to helical chirality in a square-pyramidal structure. In contrast, the helix inversion of the self-assembled <b>R-2</b> and <b>S-2</b> complexes containing an alanine analogue and two glycine moieties with Co²⁺ was followed by one step to form two distinct coexisting complex geometries having the same helical direction. In particular, the circular dichroism (CD) intensities of the self-assembled <b>R-1</b> and <b>R-2</b> complexes with Co²⁺ were 900–1500-fold amplified compared to those of free <b>R-1</b> and <b>R-2</b>. The Gibbs free energies of the self-assembled complexes with different geometries were also calculated by temperature-dependent CD observation; the square-pyramidal structure of the self-assembled <b>R-1</b> complex with Co²⁺ was more stable than the self-assembled <b>R-2</b> complex with Co²⁺. Furthermore, the self-assembled <b>R-1</b> and <b>S-1</b> complexes with 1.0 equiv of Co²⁺ could classify amino acids by their chirality

Determining Chiral Configuration of Diamines via Contact Angle Measurements on Enantioselective Alanine-Appended Benzene-Tricarboxamide Gelators

Spectroscopic techniques exist that may discern between enantiomers and assess chiral purity. A nonspectroscopic approach that may be directly observed could provide numerous benefits. Using chiral alanine-appended benzene-tricarboxamide gelators, we reveal a methanol gel system that is capable of providing visual discrimination between enantiomers of various diamines. Specifically, gelation is induced by supramolecular nanofiber assembly resulting from interaction between a chiral gelator and a diamine of opposing chirality (i.e., a heterochiral system). Upon further implementing the chiral gelator in electrospun fibers as solid state films, we revealed enantioselective surface wetting properties that allowed for determining chirality through contact angle measurements. While these two approaches of observable gelation and surface wetting offer nonspectroscopic approaches, we also find that the supramolecular nanofiber assembly was able to enhance the induced circular dichroism signal resulting from addition of chiral diamines, allowing precise quantification of their enantiomeric purity

Additional file 1 of Familial chylomicronemia syndrome: case reports of siblings with deletions of the GPIHBP1 gene

Supplementary Material

Chiral Supramolecular Gels with Lanthanide Ions: Correlation between Luminescence and Helical Pitch

We report the correlation between the fluorescence intensity and the helical pitch of supramolecular hydrogels with Tb­(III) and Eu­(III) as well as their inkjet printing patterning as an application. The luminescent gels, which exhibited three different emissions of red, green, and blue, could be prepared without and with Eu­(III) and Tb­(III). The luminescence intensity of supramolecular gels (gel-Tb and gel-Eu) composed of Tb­(III) and Eu­(III) was ca. 3-fold larger than that of the sol (<b>1</b>+Tb­(III) or <b>1</b>+Eu­(III)), which was attributed to large tilting angles between molecules. By AFM observations, these gels showed well-defined right-handed helical nanofibers formed by coordination bonds in which the helical pitch lengths were strongly dependent on the concentrations of lanthanide ions. In particular, the large luminescence intensity of gel-Tb exhibited a smaller helical pitch length than that of gel-<b>1</b> due to relatively weak π–π stacking with large tilting angles between molecules. The luminescence intensities were enhanced linearly with increasing concentrations of lanthanide ions. This is the first example of the correlation between the helical pitch length and the luminescence intensity of supramolecular materials. The coordination bonding in supramolecular hydrogels had a strong influence on rheological properties. We also developed a water-compatible inkjet printing system to generate luminescent supramolecular gels on A4-sized paper. The images of a logo and the text were composed of three different emissions and were well-printed on A4 sized paper coated with gel-<b>1</b>

Salicylimine-Based Fluorescent Chemosensor for Aluminum Ions and Application to Bioimaging

In this study, an assay to quantify the presence of aluminum ions using a salicylimine-based receptor was developed utilizing turn-on fluorescence enhancement. Upon treatment with aluminum ions, the fluorescence of the sensor was enhanced at 510 nm due to formation of a 1:1 complex between the chemosensor and the aluminum ions at room temperature. As the concentration of Al³⁺ was increased, the fluorescence gradually increased. Other metal ions, such as Na⁺, Ag⁺, K⁺, Ca²⁺, Mg²⁺, Hg²⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, Cr³⁺, Fe³⁺, and In³⁺, had no such significant effect on the fluorescence. In addition, we show that the probe could be used to map intracellular Al³⁺ distribution in live cells by confocal microscopy

Geometric Change of a Thiacalix[4]arene Supramolecular Gel with Volatile Gases and Its Chromogenic Detection for Rapid Analysis

A coordination polymer gel that is self-assembled to form a network structure between a thiacalix[4]­arene derivative (<b>L</b>) and Co²⁺ has been prepared. This gel is capable of selectively changing color in the presence of gases that yield hydrogen chloride upon hydrolysis. The UV–vis absorption spectrum of a coordination polymer gel derived from Co­(NO₃)₂ exhibits an absorption band at 527 nm and is colored red, indicating the formation of an octahedral Co²⁺ complex. Treatment with a small amount of volatile gases containing a chlorine atom (VGCl) causes a red shift of ∼150 nm, resulting in a new strong band with a maximum at 670 nm and a color change to blue. In addition, the red color of the filter paper coated with a Co­(NO₃)₂ coordination polymer gel changed to blue upon exposure to VGCl, reflecting a change in the coordination geometry. Red and blue colors of single crystals of Co²⁺ complexes were obtained from a basic solution. From X-ray crystallographic analysis, the red Co²⁺ complex corresponds to an octahedral structure, while the blue Co²⁺ complex reflects the presence of a tetrahedral structure. Thus, the induced color change of Co²⁺ gel from red to blue upon exposure to VGCl is due to the coordination geometry. The quantitative concentration of VGCl was calculated by employing the RGB histogram available in a smartphone application

Carbon-Impurity Affected Depth Elemental Distribution in Solution-Processed Inorganic Thin Films for Solar Cell Application

A common feature of the inorganic thin films including Cu­(In,Ga)­(S,Se)₂ fabricated by nonvacuum solution-based approaches is the doubled-layered structure, with a top dense inorganic film and a bottom carbon-containing residual layer. Although the latter has been considered to be the main efficiency limiting factor, (as a source of high series resistance), the exact influence of this layer is still not clear, and contradictory views are present. In this study, using a CISe as a model system, we report experimental evidence indicating that the carbon residual layer itself is electrically benign to the device performance. Conversely, carbon was found to play a significant role in determining the depth elemental distribution of final film, in which carbon selectively hinders the diffusion of Cu during selenization, resulting in significantly Cu-deficient top CISe layer while improving the film morphology. This carbon-affected compositional and morphological impact on the top CISe films is a determining factor for the device efficiency, which was supported by the finding that CISe solar cells processed from the precursor film containing intermediate amount of carbon demonstrated high efficiencies of up to 9.15% whereas the performances of the devices prepared from the precursor films with very high and very low carbon were notably poor

Self-Assembled Coumarin Nanoparticle in Aqueous Solution as Selective Mitochondrial-Targeting Drug Delivery System

The development of specifically targeted nanoparticles for subcellular organelles modified with a low-molecular-weight organic compound as drug nanocarriers can bring about wide applications in cancer therapy. However, their utility has been hampered by low selectivity, poor biodistribution, and limited efficiency. Herein, we report the aggregation behavior of a triphenylphosphonium-appended coumarin probe (<b>TPP-C</b>) in an aqueous solution and its applications as a mitochondria-targeting probe, and drug delivery carrier, which is a rare example for a low molecular-weight organic compound. The <b>TPP-C</b> formed homogeneous nanoparticles with small diameters in water as well as in mixtures of organic solvents and water. In pure water, the homogeneous nanoparticles induced J-aggregation, whereas in mixed solvents, the homogeneous nanoparticles induced H-aggregation. The luminescence intensities of nanoparticles originated from the aggregation-induced emission (AIE) effect in pure water and also in mixtures of organic solvents and water. These findings indicate that the AIE effect of <b>TPP-C</b> was dependent on the solvent. More interestingly, the <b>TPP-C</b> nanoparticles selectively accumulated in mitochondria. The <b>TPP-C</b> nanoparticles alone exhibited noncytotoxicity toward cancer cells. However, with the encapsulation of the anticancer drug doxorubicin (DOX) into the <b>TPP-C</b> nanoparticles, the DOX was efficiently delivered to the mitochondria. These results indicated that the proposed system demonstrates promise as a platform for future clinical medication, particularly for specific suborganelle-targeted drug delivery systems for cancer therapy

Self-Assembled Tb³⁺ Complex Probe for Quantitative Analysis of ATP during Its Enzymatic Hydrolysis via Time-Resolved Luminescence in Vitro and in Vivo

To more accurately assess the pathways of biological systems, a probe is needed that may respond selectively to adenosine triphosphate (ATP) for both in vitro and in vivo detection modes. We have developed a luminescence probe that can provide real-time information on the extent of ATP, ADP, and AMP by virtue of the luminescence and luminescence lifetime observed from a supramolecular polymer based on a <i>C</i>₃ symmetrical terpyridine complex with Tb³⁺ (<b>S1-Tb</b>). The probe shows remarkable selective luminescence enhancement in the presence of ATP compared to other phosphate-displaying nucleotides including adenosine diphosphate (ADP), adenosine monophosphate (AMP), guanosine triphosphate (GTP), thymidine triphosphate (TTP), H₂PO₄^– (Pi), and pyrophosphate (PPi). In addition, the time-resolved luminescence lifetime and luminescence spectrum of <b>S1-Tb</b> could facilitate the quantitative measurement of the exact amount of ATP and similarly ADP and AMP within living cells. The time-resolved luminescence lifetime of <b>S1-Tb</b> could also be used to quantitatively monitor the amount of ATP, ADP, and AMP in vitro following the enzymatic hydrolysis of ATP. The long luminescence lifetime, which was observed into the millisecond range, makes this <b>S1-Tb</b>-based probe particularly attractive for monitoring biological ATP levels in vivo, because any short lifetime background fluorescence arising from the complex molecular environment may be easily eliminated