scholarly journals Guest-induced fluorescence property of macrocyclic boronic ester

2014 ◽  
Vol 70 (a1) ◽  
pp. C672-C672
Author(s):  
Haruki Sugiyama ◽  
Kohei Johmoto ◽  
Hidehiro Uekusa ◽  
Yuji Kikuchi ◽  
Hiroki Takahagi ◽  
...  
Keyword(s):  
Crystal Packing ◽  
Uv Light ◽  
Condensation Reaction ◽  
Fluorescence Property ◽  
Channel Structure ◽  
Diffusion Method ◽  
Blue Color ◽  
Guest Molecules ◽  
One Dimensional ◽  
Naphthalene Molecule

Macrocyclic boronic esters (1) are obtained as a self-assembled molecule by condensation reaction between rac-tetrol (2) and 1,4-naphthalenediboronic acid (3) in the presence of toluene molecule [1]. In the crystal, this macrocyclic molecules form a charasteristic one dimensional channel structure that accommodates various small molecules. Interestingly, reversible desorption / absorption phenomena of guest molecules is observed without significant crystal packing change, meaning this crystal may have guest storage, separation, and catalytic abilities. In the course of exploring further functional aspects of the molecule, we give fluorescence property to this crystal by inclusion of acene molecules into this robust one dimensional channel structure. Naphthalene inclusion crystal was obtained by the diffusion method. The crystal structure is isostructural to known crystals, that is, a naphthalene molecule is included in a channel and sandwiched by two naphthalene moieties of the macrocyclic molecule (inter planar distance is about 3.6 angstrom). Under UV light, a blue color fluorescence observed in this crystal, suggesting the guest naphthalene molecule contributes the fluorescence property. After heating by 200 degrees C, the naphthalene was released to leave isostructural apohost crystal without fluorescence property. However, by naphthalene vapor exposure to the apohost crystal, the fluorescence property was recovered, which means naphthalene desorption and absorption are possible in crystalline state. Moreover Anthracene and Tetracene inclusion crystal were obtained, and they also showed light blue and yellow color fluorescence under UV light, respectively. Thus, the fluorescence function was successfully realized by inclusion of acene molecule in the one dimensional channel of the crystals, and furthermore the fluorescent color can be controlled by changing acene molecules.

scholarly journals Photochromism change by conformation control in macrocyclic boronic ester cavity

2014 ◽  
Vol 70 (a1) ◽  
pp. C654-C654
Author(s):  
Kohei Johmoto ◽  
Hidehiro Uekusa ◽  
Yuji Kikuchi ◽  
Hiroki Takahagi ◽  
Kosuke Ono ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Molecular Conformation ◽  
Uv Light ◽  
Covalent Bond ◽  
Channel Structure ◽  
Guest Molecules ◽  
Parallel Form ◽  
Boronic Ester ◽  
Residual Electron Density ◽  
Covalent Bond Formation

N-salicylideneaniline derivatives are known to show photochromism by UV light, and it depends on the molecular conformation in the crystal. The twisted molecule is photochromic but the planar one is not[1,2]. N-salicylidene-2-aminopyridine (2SAP) always has a planar conformation due to the chemical structure without steric hindrance, therefore 2SAP is known as non-photochromic. However, by confining the molecule in a cavity of the macrocyclic boronic ester 1[3], the conformation and photochromism can be controlled. The inclusion crystal of 1 (homo-parallel form) has a special feature to have a channel type crystal structure in which the macrocyclic ring aligned one-dimensionally to include guest molecules. Interestingly, the crystals can reversibly absorb/desorb guests maintaining the crystal structure, because the channel structure is robust. To exchange the included guests, the crystal of 1(homo-parallel form) was immersed in the melt of 2SAP at 90°C. The obtained inclusion crystal showed photochromism. In the crystal structure, the shape of residual electron density for 2SAP indicated the conformation of 2SAP was twisted due to the confining in the cavity, which is the reason for photochromism. On the other hand, the recrystallization of 1 and 2SAP from THF / hexane solution unexpectedly gave hetero-antiparallel form of 1 because of the dynamic covalent bond formation in the boronic esters (Fig.). As this hetero-antiparallel form has planar cavity in the molecule, the conformation of the included guest molecule, 2SAP, is also planar as always seen. Therefore the inclusion crystal is non-photochromic. Thus, photochromism change of 2SAP was realized by conformational control through confining in the cavity of macrocyclic boronic ester.

Dimeric and polymeric [Eu(tta)3L] complexes (tta = thenoyltrifluoroacetonato, L = 4,4'-bipyridine, trans-1,2-bis(4-pyridyl)ethylene, 4,4'-bipyridine- N,N'-dioxide)

2001 ◽  
Vol 79 (7) ◽  
pp. 1187-1193 ◽  
Author(s):  
Corey Seward ◽  
Suning Wang
Keyword(s):  
Uv Light ◽  
Chain Structure ◽  
Dimensional Chain ◽  
Two Dimensional ◽  
No Emission ◽  
Europium Complexes ◽  
Guest Molecules ◽  
One Dimensional ◽  
Red Color ◽  
Coordination Bonds

The reaction of Eu(tta)3 (tta = thenoyltrifluoroacetonato) with 4,4'-bipyridine (bipy), trans-1,2-bis(4-pyridyl)ethylene (bipyete), and 4,4'-bipyridine-N,N'- dioxide (bipyo) yielded three distinct complexes [Eu(tta)3(bipy)(H2O)] (1), [Eu(tta)3(bipyete)(CH3OH)]·CH3OH·bipyete (2), and [Eu(tta)3(bipyo)]·CH3OH (3), respectively. Compounds 1 and 2 have a hydrogen-bond linked dimer structure, while 3 has a one-dimensional chain structure linked by coordination bonds, which further forms two-dimensional arrays, resulting in an intercalation lattice that hosts methanol guest molecules. In solution compounds 1 and 2 emit a red color, characteristic of Eu(III), when irradiated by UV light, while compound 3 has no emission either in solution or the solid state.Key words: europium complexes, luminescence, structure, 4,4'-bipyridine, 1,2-bis(4-pyridyl)ethylene, 4,4'-bipyridine-N,N'-dioxide.

scholarly journals Macrocyclic Boronic Ester: Porous and Host-Guest Structures Revealed by SDPD

2014 ◽  
Vol 70 (a1) ◽  
pp. C635-C635
Author(s):  
Hidehiro Uekusa ◽  
Kotaro Fujii ◽  
Kohei Johmoto ◽  
Yuji Kikuchi ◽  
Hiroki Takahagi ◽  
...  
Keyword(s):  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Packing ◽  
Channel Structure ◽  
Supramolecular Interactions ◽  
Release Mechanism ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Boronic Ester

Diboronic acid and racemic tetrol are found to form a self-assembled macrocyclic boronic ester in the presence of appropriate guest molecules[1]. In the crystal, stacking of macrocyclic ring is observed to form infinite channel structure accommodating guest molecules by supramolecular interactions. In such structure, it is important to investigate the guest uptake and release mechanism via the crystal structure determination of the guest-free apohost. However, the apohost crystal can only be obtained by guest release process by heating, which results to form powder crystals. In this study, the structure of apohost was determined by "Structure Determination from Powder X-ray Diffraction data" technique [2][3] and the structural change by guest sorption and desorption processes were investigated. The powder X-ray diffraction pattern of the toluene inclusion crystal and the apohost crystal, which was obtained by heating of the inclusion crystal, are significantly different. However, even after the guest release, the apohost structure determined from the powder X-ray diffraction data was found to retain its crystal packing with one dimensional guest free channel. Interestingly, the apohost crystal easily absorbs the toluene and other aromatic molecules when the vapor was applied, and the crystal transforms into the guest inclusion crystal. Also, such vapor application is interesting method to switch the physicochemical property of the crystal. When naphthalene vapor was applied to the apohost crystal, naphthalene inclusion crystal was readily formed, and it became fluorescent crystal. This property was switched off by heating and guest desorption. In summary, the macrocyclic boronic ester is promising compound that forms inclusion supramolecular crystal, which can be utilized as guest storage / release, separate, protect, and other physicochemical functional material.

Synthesis and Structure of a Clathrated Two-Dimensional Metal-Organic Framework: [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2·H2O (L = Bis(1-pyrazinylethylidene)hydrazine)

2008 ◽  
Vol 73 (1) ◽  
pp. 24-31
Author(s):  
Dayu Wu ◽  
Genhua Wu ◽  
Wei Huang ◽  
Zhuqing Wang
Keyword(s):  
Metal Organic Framework ◽  
Channel Structure ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Square Planar ◽  
Metal Organic ◽  
Aqueous Meoh ◽  
Organic Framework

The compound [Cd(4,4'-bpy)2(H2O)2](ClO4)2·(L)2 was obtained by the reaction of Cd(ClO4)2, bis(1-pyrazinylethylidene)hydrazine (L) and 4,4'-bipyridine in aqueous MeOH. Single-crystal X-ray diffraction has revealed its two-dimensional metal-organic framework. The 2-D layers superpose on each other, giving a channel structure. The square planar grids consist of two pairs of shared edges with Cd(II) ion and a 4,4'-bipyridine molecule each vertex and side, respectively. The square cavity has a dimension of 11.817 × 11.781 Å. Two guest molecules of bis(1-pyrazinylethylidene)hydrazine are clathrated in every hydrophobic host cavity, being further stabilized by π-π stacking and hydrogen bonding. The results suggest that the hydrazine molecules present in the network serve as structure-directing templates in the formation of crystal structures.

scholarly journals Variability and improvement of optical and antimicrobial performances for CQDs/mesoporous SiO2/Ag NPs composites via in situ synthesis

2021 ◽  
Vol 10 (1) ◽  
pp. 403-411
Author(s):  
Youliang Cheng ◽  
Mingjie Wang ◽  
Changqing Fang ◽  
Ying Wei ◽  
Jing Chen ◽  
...  
Keyword(s):  
Uv Light ◽  
Carbon Quantum Dots ◽  
Diffusion Method ◽  
Ag Nps ◽  
Uniform Size ◽  
High Antibacterial Activity ◽  
Fluorescent Materials ◽  
Potential Applications ◽  
Mesoporous Sio2

Abstract To change the optical properties and improve the antibacterial performances of carbon quantum dots (CQDs) and Ag NPs, mesoporous SiO2 spheres were combined with them to form the composites. In this paper, CQDs with a uniform size of about 3.74 nm were synthesized using glucose as carbon source. Then, CQDs/mesoporous SiO2/Ag NPs composites were obtained in situ under UV light irradiating by using mesoporous SiO2 and Ag NO3 as the carrier and silver resource, respectively. The diameter of CQDs/mesoporous SiO2/Ag NPs particles was in the range of 200–250 nm. With the increase in irradiating time, the red-shift in the UV-Vis spectrum for as-prepared CQDs/mesoporous SiO2/Ag NPs composites was found, and the adsorption peak was widened. In addition, the composites showed a high antibacterial activity against Staphylococcus aureus and Escherichia coli via disc diffusion method. These results indicated that inhibition circles for Ag NPs/mesoporous SiO2/CQDs and mesoporous SiO2/Ag NPs were similar in diameter. Furthermore, the two composites had a better bactericidal performance compared with other particles. Therefore, as-prepared CQDs/mesoporous SiO2/Ag NPs composites in this paper have great potential applications for fluorescent materials and antibacterial materials.

scholarly journals One-Dimensional Organic–Inorganic Material (C6H9N2)2BiCl5: From Synthesis to Structural, Spectroscopic, and Electronic Characterizations

2021 ◽  
Vol 22 (4) ◽  
pp. 2030
Author(s):  
Hela Ferjani ◽  
Hammouda Chebbi ◽  
Mohammed Fettouhi
Keyword(s):  
Hydrogen Bonding ◽  
Density Functional ◽  
Crystal Packing ◽  
Diffuse Reflectance Spectrum ◽  
Enrichment Ratio ◽  
One Dimensional ◽  
Organic Part ◽  
Fukui Indices ◽  
The Stability ◽  
The One

The new organic–inorganic compound (C6H9N2)2BiCl5 (I) has been grown by the solvent evaporation method. The one-dimensional (1D) structure of the allylimidazolium chlorobismuthate (I) has been determined by single crystal X-ray diffraction. It crystallizes in the centrosymmetric space group C2/c and consists of 1-allylimidazolium cations and (1D) chains of the anion BiCl52−, built up of corner-sharing [BiCl63−] octahedra which are interconnected by means of hydrogen bonding contacts N/C–H⋯Cl. The intermolecular interactions were quantified using Hirshfeld surface analysis and the enrichment ratio established that the most important role in the stability of the crystal structure was provided by hydrogen bonding and H···H interactions. The highest value of E was calculated for the contact N⋯C (6.87) followed by C⋯C (2.85) and Bi⋯Cl (2.43). These contacts were favored and made the main contribution to the crystal packing. The vibrational modes were identified and assigned by infrared and Raman spectroscopy. The optical band gap (Eg = 3.26 eV) was calculated from the diffuse reflectance spectrum and showed that we can consider the material as a semiconductor. The density functional theory (DFT) has been used to determine the calculated gap, which was about 3.73 eV, and to explain the electronic structure of the title compound, its optical properties, and the stability of the organic part by the calculation of HOMO and LUMO energy and the Fukui indices.

scholarly journals Crystal structure and Hirshfeld surface analysis of 3-octyl-4-oxo-2,6-bis(3,4,5-trimethoxyphenyl)piperidinium chloride

2018 ◽  
Vol 74 (7) ◽  
pp. 931-934
Author(s):  
Rubina Siddiqui ◽  
Urooj Iqbal ◽  
Zafar Saeed Saify ◽  
Shammim Akhter ◽  
Sammer Yousuf
Keyword(s):  
Surface Analysis ◽  
Crystal Packing ◽  
Condensation Reaction ◽  
Chair Conformation ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
One Pot ◽  
Compound C ◽  
Mannich Condensation ◽  
Centrosymmetric Dimers

The title compound, C31H46NO7 +·Cl−, was synthesized by a one-pot Mannich condensation reaction. In the molecule, the piperidinone ring adopts a chair conformation, and the trimethoxy-substituted benzene rings and octyl chain are arranged equatorially. In the crystal, centrosymmetric dimers are linked into layers parallel to (011) by N—H...Cl and C—H...Cl hydrogen bonds. A Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are O...H (20.5%) interactions followed by C...H (7.8%), Cl...H (5.5%), C...C (1.2%), C...O (0.5%) and Cl...O (0.4%) interactions.

Green synthesis, characterization and antimicrobial activities of Copper nanoparticles from the rhizomes extract of Picrorhiza kurroa

2021 ◽  
Vol 09 ◽  
Author(s):  
Vinit Prakash ◽  
Anjana Kumari ◽  
Harpreet Kaur ◽  
Manoj Kumar ◽  
Sumeet Gupta ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Copper Nanoparticles ◽  
Antimicrobial Activities ◽  
Diffusion Method ◽  
Spectral Studies ◽  
Blue Color ◽  
Picrorhiza Kurroa ◽  
Fungal Strains ◽  
Gastrointestinal Problems ◽  
Hydroethanolic Extract

Background: Green synthesized nanoparticles from the solvent extract of various plant parts show better biological activities as compared to parent solvent plant extract. Traditionally rhizomes of Picrorhiza kurroa are used to cure various diseases like diarrhea, fever, jaundice, eye infection, skin problems, asthma, arthritis, cancer, diabetes, gastrointestinal problems. Objectives: Present study describes the synthesis of copper nanoparticles from a hydroethanolic extract of P. kurroa rhizomes (CuNPs-Pk) and their evaluation for antimicrobial activities against gram-negative, gram-positive bacterial, and fungal strains. Methods: The solution of copper sulfate and hydroethanolic extract of rhizomes of P. kurroa was mixed with help of a magnetic stirrer at 60°C temperature for 1 h. The blue color of CuSO4.5H2O changed to brownish-black colored copper nanoparticles within 10 minutes. These nanoparticles were centrifuged at 4000 rpm for 20 min, washed with ethanol, followed by deionized water, dried, and were characterized by Ultra violet–visible (UV-Vis) absorption spectra, Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM). Different concentrations of hydroethanolic extract of Picrorhiza kurroa rhizomes (HEEPk), CuNPs-Pk and copper oxide nanoparticles (bare CuO) ranging from 100-400 ppm had been studied against selected bacterial and fungal strains by using the well plate diffusion method. Ciprofloxin and fluconazole were used as standard and Dimethyl sulfoxide (DMSO) as a control for selected strains. Results: The UV–Vis spectral studies confirmed the surface plasmon resonance of green-synthesized CuNPs-Pk. The particle size was found to be 275-285 nm. FTIR analysis of biosynthesis nanoparticles have been confirm the presence of various functional groups (flavonoids, glycosides, tannins, phenols). SEM and TEM of biosynthesized nanoparticles have predicted their spheric al shape and their size (20-40 nm) and These particles have shown effective antimicrobial activities against selected pathogenic organisms viz. Escherichia coli, Staphylococcus aureus, and Aspergillus niger than that of HEEPk and bare CuO. Conclusions: The CuNPs-Pk show effective antimicrobial activities against bacterial and fungal pathogens as compared to HEEPk and bare CuO.

scholarly journals Synthesis, infra red characterization and antimicrobial evaluation of Schiff bases derived from 1, 3-diphenylprop-2-en-1-one and 1-phenyl-3-(4-chlorophenyl)-prop-2-en-1-one

2021 ◽  
Vol 46 (2) ◽  
Author(s):  
A. E. Aiwonegbe ◽  
C. O. Usifoh
Keyword(s):  
Absorption Band ◽  
Schiff Bases ◽  
Condensation Reaction ◽  
Antimicrobial Properties ◽  
Decomposition Temperature ◽  
Carbonyl Oxygen ◽  
Diffusion Method ◽  
Oxygen Absorption ◽  
Microbial Properties ◽  
Percentage Yield

Chalcones were synthesized via Claisen-Schmidt condensation between various substituted acetophenone and benzaldehyde using 20% cold alcoholic KOH as catalyst. Two Schiff bases were synthesized through the condensation reaction of the synthesized chalcones with 2,4-dinitrophenylhydrazine using concentrated H2SO4 as catalyst. The antimicrobial properties of the Schiff bases were determined using the standard disc diffusion method of anti-microbial sensitivity according to CLSI. The results of anti-microbial analysis were compared to ciprofloxacin and ampicillin as reference standards. The first Schiff base was N-(2,4-Dinitro-phenyl)-N'-(1,3-diphenyl-allylidene)-hydrazine (SB1), a hydrazone of 1,3-diphenylprop-2-en-1-one and the second was N-[3-(4-chloro-phenyl)-1-phenyl-allylidene]-N'-(2,4-dinitro-phenyl)-hydrazine (SB2), a hydrazone of 1-phenyl-3-(4-chlorophenyl)-prop-2-en-1-one. SB1 had a percentage yield of 97.57% and a decomposition temperature of 231-2340C while SB2 gave 98.74% as percentage yield and a melting point of 216-2180C. SB1 showed anti-microbial properties while SB2 showed no anti-microbial properties when both were tested against Staphylococcus aureus and Pseudomonas aeruginosa at a concentration of 10 mg/mL. SB1 had a diameter zone of inhibition of 4-6 mm for P. aeruginosa and 7-9 mm for S. aureus. SB1 was more effective against g positive than g negative bacteria at a concentration of 10 mg/L. The presence of the major absorption band in the range of 350-375 nm, attributable to the n-π* transition of aromatic ketones in the UV spectra of the synthesized chalcones gave credence to their proposed aromatic structure. The presence of strong bands at 1604 cm-1 for SB1 and 1601cm-1 for SB2 and the absence of carbonyl oxygen absorption band in their IR spectra gave credence to the formation of Schiff bases.

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