Synthesis and vibrational study of a 1:1 stoichiometric complex of hydronium tetrafluoroborate and 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6)

1982 ◽  
Vol 60 (7) ◽  
pp. 853-861 ◽  
Author(s):  
Robert Chênevert ◽  
André Rodrigue ◽  
Marie Pigeon-Gosselin ◽  
Rodrigue Savoie
Keyword(s):  
Aqueous Solution ◽  
Transition Temperature ◽  
Crown Ether ◽  
Room Temperature ◽  
Organic Medium ◽  
Remarkable Property ◽  
H Nmr ◽  
Vibrational Study ◽  
Raman And Ir Spectroscopy ◽  
Stoichiometric Complex

The macrocyclic ether 1,4,7,10,13,16-hexaoxaoctadecane (18-crown-6) has the remarkable property of being able to transfer the hydronium (H3O+) ion from an aqueous solution to an organic medium. This property has been used to synthetize a 1:1 stoichiometric complex of this ether with hydronium tetrafluoroborate. This complex is very stable (mp 145 °C) and dissolves readily, without decomposition, in solvents such as CHCl3. The presence of the H3O+ and BF4− ions in the complex has been confirmed by chemical analysis, and by 1H nmr, Raman, and ir spectroscopy. The vibrational spectra indicate that a conformational change of the crown ether takes place in the complex over the temperature range −50 °C to −100 °C. The symmetry of the crown ether, which appears to be relatively high at room temperature, is considerably reduced below the transition temperature.

Preparation of poly(methyl methacrylate) nano-latexes via UV irradiation in the presence of iron aqueous solution

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Hong Zhang ◽  
Limin Zang ◽  
Jiahe Luo ◽  
Jinshan Guo
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Glass Transition ◽  
Transition Temperature ◽  
Methyl Methacrylate ◽  
High Efficiency ◽  
Particle Sizes ◽  
H Nmr ◽  
Reaction Conversion ◽  
Emulsifying Agent

AbstractThe UV-initiated emulsion polymerization of methyl methacrylate (MMA) in the presence of FeCl3 was studied. The photopolymerization presented high efficiency even though using a small percentage of photoinitiator. The entire polymerization could be performed within 10 min and displayed a conversion higher than 90% at ambient temperature. The particle sizes could be tuned in the range of 20-90 nm. The effects of content of initiator and emulsifying agent upon the reaction conversion, distribution of molecular weight, diameter of particles and glass-transition temperature were examined. 1H-NMR technique was used to investigate the structural properties of PMMA.

scholarly journals Synthesis and Antimicrobial Activity of Some Chalcone Derivatives

2008 ◽  
Vol 5 (3) ◽  
pp. 461-466 ◽  
Author(s):  
Y. Rajendra Prasad ◽  
A. Lakshmana Rao ◽  
R. Rambabu
Keyword(s):  
Aqueous Solution ◽  
Antimicrobial Activity ◽  
Potassium Hydroxide ◽  
Room Temperature ◽  
Antimicrobial Agents ◽  
Aromatic Aldehydes ◽  
Plate Method ◽  
H Nmr ◽  
Antibacterial And Antifungal Activities ◽  
Antibacterial And Antifungal

In an effort to develop antimicrobial agents, a series of chalcones were prepared by Claisen-Schmidt condensation of appropriate acetophenones with appropriate aromatic aldehydes in the presence of aqueous solution of potassium hydroxide and ethanol at room temperature. The synthesized compounds were characterized by means of their IR,1H-NMR spectral data and elemental analysis. All the compounds were tested for their antibacterial and antifungal activities by the cup plate method.

Symmetry, disorder, and dynamics in solid crown ether complexes: 2H NMR studies of 15-crown-5·NaI, 15-crown-5·NaClO4, and 21-crown-7·KI

1999 ◽  
Vol 77 (11) ◽  
pp. 1911-1921 ◽  
Author(s):  
G W Buchanan ◽  
M Gerzain ◽  
C I Ratcliffe
Keyword(s):  
Phase Transitions ◽  
High Temperature ◽  
Crown Ether ◽  
Detailed Analysis ◽  
Room Temperature ◽  
2H Nmr ◽  
Nmr Studies ◽  
H Nmr ◽  
Line Shapes ◽  
Crown Ether Complexes

2H NMR line shapes have been obtained as a function of temperature for partially deuteriated 15-crown-5·NaI, 15-crown-5·NaClO4 and 21-crown-7·KI. Sudden changes in the line shapes above 330 K correspond to phase transitions: DSC shows transitions at 338, 347 K for 15-crown-5·NaI, and 356, 374, 383 K for 15-crown-5·NaClO4. The 2H NMR line shapes for the room temperature (RT) phases show the onset of a motion of the macrocycles above 200K, which is rapid a little above room temperature. Through detailed analysis of the complicated line shapes it has been shown that the most consistent interpretation of the dynamics in these RT phases is a "merry-go-round" type of motion similar to that found for 18-crown-6 and 12-crown-4 complexes in which O-CH2-CH2 units exchange sites around the ring, simultaneously adjusting their conformation to fit the site. In the high-temperature phases of all three complexes all the ring atoms are dynamically equivalent. This can only happen through a combination of increased symmetry and disorder for which possible models have been devised.Key words: 2H NMR, crown ether complexes, dynamics, disorder.

scholarly journals Synthesis and Biological Evaluation of Some New Chalcones Containing 2,5-Dimethylfuran Moiety

2011 ◽  
Vol 8 (2) ◽  
pp. 541-546 ◽  
Author(s):  
S. Sridhar ◽  
S. C. Dinda ◽  
Y. Rajendra Prasad
Keyword(s):  
Aqueous Solution ◽  
Spectral Data ◽  
Potassium Hydroxide ◽  
Room Temperature ◽  
Aromatic Aldehydes ◽  
Biological Evaluation ◽  
Significant Activity ◽  
H Nmr ◽  
Elemental Analyses ◽  
Synthesis And Biological Evaluation

A series of new chalcones(3a-g)were prepared by Claisen-Schmidt condensation of 3-acetyl-2,5-dimethylfuran with various substituted aromatic aldehydes in presence of aqueous solution of potassium hydroxide and ethanol at room temperature. The synthesized chalcones were characterized by means of their IR,1H NMRspectral data and elemental analyses. When these chalcones were evaluated for antimicrobial and anti-inflammatory activities, some of them were found to possess significant activity, when compared to standard drugs.

Phase transition metal–crown ether coordination compounds tuned by metal ions

2016 ◽  
Vol 45 (3) ◽  
pp. 1000-1006 ◽  
Author(s):  
Qiong Ye ◽  
Hui-Ting Wang ◽  
Lin Zhou ◽  
Li-Hui Kong ◽  
Heng-Yun Ye ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Transition Temperature ◽  
Transition Metal ◽  
Crown Ether ◽  
Metal Ions ◽  
Phase Transition Temperature ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Metal Center

(15-Crown-5)(BiCl3) and (15-crown-5)(SbCl3) are discovered to show phase transitions above room temperature, where the phase transition temperature relates to the metal center.

Removal of Murexide Dye from Aqueous Solution Using A Novel Schiff Base Tin(IV) Compound

2021 ◽  
Author(s):  
SEDA KARAYÜNLÜ BOZBAS ◽  
Begüm Canan Yıldız Aras ◽  
Muhammed Karabulut ◽  
Asgar Kayan
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Room Temperature ◽  
H Nmr ◽  
Exothermic Process ◽  
Initial Ph ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
C Nmr

Abstract A Schiff base tin (IV) compound was synthesized by reactions between 2-((E)-(p-tolylimino)methyl)phenol (TIMPH) and butyltin trichloride in 2:1 mole ratio in ethanol at room temperature. [SnBuCl3(TIMPH)2] was characterized by FT-IR, 1H-NMR, 13C-NMR spectroscopy, elemental analysis, and mass spectrometry. Optimization of Murexide dye from aqueous solution was performed by examining; effect of contact time, initial pH, adsorbent amount, initial dye concentration and temperature on the tin adsorbent. The highest adsorption recovery value of was 98.00% and the adsorption capacity was 248.8 mg/g at the end of 20 minutes at 100 mg/L dye concentration while the temperature was 25°C and the pH was 3. Langmuir, Freundlich, and Temkin adsorption isotherms were calculated at 25 ºC. The highest R2 value was found 0.099 for the Langmuir isotherm model. The adsorption characteristics of murexide dye showed that adsorption kinetic obeyed the pseudo-second-order kinetics, and the thermodynamic data suggested the spontaneous and exothermic process.

Enantioselective Recognition of Chiral Guests by the Water-Soluble Chiral Keplerate {Mo132} Spherical Capsule with 30 Inner Lactate Ligands

2019 ◽  
Author(s):  
Nancy Watfa ◽  
Weimin Xuan ◽  
Zoe Sinclair ◽  
Robert Pow ◽  
Yousef Abul-Haija ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Chiral Recognition ◽  
Association Constants ◽  
Water Soluble ◽  
Enantioselective Recognition ◽  
H Nmr ◽  
Dosy Nmr ◽  
Spherical Capsule ◽  
Surface Pores ◽  
Guest Chemistry

Investigations of chiral host guest chemistry are important to explore recognition in confined environments. Here, by synthesizing water-soluble chiral porous nanocapsule based on the inorganic metal-oxo Keplerate-type cluster, {Mo<sub>132</sub>} with chiral lactate ligands with the composition [Mo<sub>132</sub>O<sub>372</sub>(H<sub>2</sub>O)<sub>72</sub>(<i>x-</i>Lactate)<sub>30</sub>]<sup>42-</sup> (<i>x</i> = D or L), it was possible to study the interaction with a chiral guest, L/D-carnitine and (<i>R</i>/<i>S</i>)-2-butanol in aqueous solution. The enantioselective recognition was studied by quantitative <sup>1</sup>H NMR and <sup>1</sup>H DOSY NMR which highlighted that the chiral recognition is regulated by two distinct sites. Differences in the association constants (K) of L- and D-carnitine, which, due to their charge, are generally restricted from entering the interior of the host, are observed, indicating that their recognition predominantly occurs at the surface pores of the structure. Conversely, a larger difference in association constants (K<i><sub>S</sub></i>/K<i><sub>R</sub></i> = 3) is observed for recognition within the capsule interior of (<i>R</i>)- and (<i>S</i>)-2-butanol.

scholarly journals Practical Synthesis of 2-Iodosobenzoic Acid (IBA) without Contamination by Hazardous 2-Iodoxybenzoic Acid (IBX) under Mild Conditions

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1897
Author(s):  
Hideyasu China ◽  
Nami Kageyama ◽  
Hotaka Yatabe ◽  
Naoko Takenaga ◽  
Toshifumi Dohi
Keyword(s):  
Aqueous Solution ◽  
Room Temperature ◽  
Practical Method ◽  
Hypervalent Iodine ◽  
Mild Conditions ◽  
Sequential Procedures ◽  
Iodine Compounds ◽  
Practical Synthesis ◽  
Iodosobenzoic Acid ◽  
Lower Temperature

We report a convenient and practical method for the preparation of nonexplosive cyclic hypervalent iodine(III) oxidants as efficient organocatalysts and reagents for various reactions using Oxone® in aqueous solution under mild conditions at room temperature. The thus obtained 2-iodosobenzoic acids (IBAs) could be used as precursors of other cyclic organoiodine(III) derivatives by the solvolytic derivatization of the hydroxy group under mild conditions of 80 °C or lower temperature. These sequential procedures are highly reliable to selectively afford cyclic hypervalent iodine compounds in excellent yields without contamination by hazardous pentavalent iodine(III) compound.

scholarly journals Self-assembly induced luminescence of Eu3+-complexes and application in bioimaging

2021 ◽  
Author(s):  
Ping-Ru Su ◽  
Tao Wang ◽  
Pan-Pan Zhou ◽  
Xiao-Xi Yang ◽  
Xiao-Xia Feng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Luminescence Intensity ◽  
Self Assembly ◽  
Room Temperature ◽  
Molecular Motion ◽  
Proof Of Concept ◽  
Room Temperature Phosphorescence ◽  
New Strategy ◽  
Size Controlled

Abstract Design and engineering of highly efficient emitting materials with assembly-induced luminescence, such as room temperature phosphorescence (RTP) and aggregation-induced emission (AIE), have stimulated extensive efforts. Here, we propose a new strategy to obtain size-controlled Eu3+-complex nanoparticles (Eu-NPs) with self-assembly induced luminescence (SAIL) characteristics without encapsulation or hybridization. Compared with previous RTP or AIE materials, the SAIL phenomena of increased luminescence intensity and lifetime in aqueous solution for the proposed Eu-NPs are due to the combined effect of self-assembly in confining the molecular motion and shielding the water quenching. As a proof of concept, we also show that this system can be further applied in bioimaging, temperature measurement and HClO sensing. The SAIL activity of the rare-earth (RE) system proposed here offers a further step forward on the roadmap for the development of RE light conversion systems and their integration in bioimaging and therapy applications.

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