scholarly journals Development of Taste Sensor to Detect Non-Charged Bitter Substances

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3455 ◽  
Author(s):  
Jumpei Yoshimatsu ◽  
Kiyoshi Toko ◽  
Yusuke Tahara ◽  
Misaki Ishida ◽  
Masaaki Habara ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Pharmaceutical Products ◽  
Dihydroxybenzoic Acid ◽  
Intermolecular Hydrogen Bonds ◽  
Detection Mechanism ◽  
Electric Charge Density ◽  
Allosteric Mechanism ◽  
Potentiometric Measurement ◽  
Intramolecular Hydrogen ◽  
Taste Sensor

A taste sensor with lipid/polymer membranes is one of the devices that can evaluate taste objectively. However, the conventional taste sensor cannot measure non-charged bitter substances, such as caffeine contained in coffee, because the taste sensor uses the potentiometric measurement based mainly on change in surface electric charge density of the membrane. In this study, we aimed at the detection of typical non-charged bitter substances such as caffeine, theophylline and theobromine included in beverages and pharmaceutical products. The developed sensor is designed to detect the change in the membrane potential by using a kind of allosteric mechanism of breaking an intramolecular hydrogen bond between the carboxy group and hydroxy group of aromatic carboxylic acid (i.e., hydroxy-, dihydroxy-, and trihydroxybenzoic acids) when non-charged bitter substances are bound to the hydroxy group. As a result of surface modification by immersing the sensor electrode in a modification solution in which 2,6-dihydroxybenzoic acid was dissolved, it was confirmed that the sensor response increased with the concentration of caffeine as well as allied substances. The threshold and increase tendency were consistent with those of human senses. The detection mechanism is discussed by taking into account intramolecular and intermolecular hydrogen bonds, which cause allostery. These findings suggest that it is possible to evaluate bitterness caused by non-charged bitter substances objectively by using the taste sensor with allosteric mechanism.

scholarly journals The Effects of the Solvents on the Macrocyclic Structures: From Rigid Pillararene to Flexible Crown Ether

2021 ◽  
Author(s):  
Shuangshuang Wang ◽  
Yanzhen Yin ◽  
Jian Gao ◽  
Xingtang Liang ◽  
Haixin Shi
Keyword(s):  
Hydrogen Bonds ◽  
Structural Design ◽  
Structural Features ◽  
Intermolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonds ◽  
Effect Of Solvents ◽  
Dynamics Simulations ◽  
Intramolecular Hydrogen ◽  
Macrocyclic Molecules ◽  
Polarity Of Solvents

The differences in the macrocyclic structures lead to different flexibilities, and yet the effect of solvents on the conformations is not clear so far. In this work, the conformations of four representational macrocyclic molecules (pillar[5]arene, p-tert-butyl calix[6]arene, benzylic amide macrocycle and dibenzo-18-crown-6) in three solvents with distinct polarity have been studied by all-atom molecular dynamics simulations. The structural features of the macrocycles in the solvents indicate that the conformations are related to the polarity of the solvents and the formation of hydrogen bonds. For the pillar[5]arene, the benzylic amide macrocycle and the dibenzo-18-crown-6, that cannot form intramolecular hydrogen bonds, the polarity of solvents is the major contributing factor in the conformations. The formation of intramolecular hydrogen bonds, in contrast, determinates the conformations of the calix[6]arene. Furthermore, the slight fluctuations of the structures will result in tremendous change of the intramolecular hydrogen bonds of the macrocycles and the intermolecular hydrogen bonds between the macrocycles and the solvents. The current theoretical studies that serve as a basis for the macrocyclic chemistry are valuable for the efficient structural design of the macrocyclic molecules.

N-(4-Methylbenzoyl)-N′-(4-methylphenyl)thiourea

2007 ◽  
Vol 63 (11) ◽  
pp. o4395-o4395
Author(s):  
S. Aminah A. Razis ◽  
M. Sukeri M. Yusof ◽  
A. Maisara Kadir ◽  
Bohari M. Yamin
Keyword(s):  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Compound ◽  
Intermolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonds ◽  
Compound C ◽  
Intramolecular Hydrogen

The title compound, C16H16N2OS, adopts a trans–cis configuration of the 4-methylbenzoyl and 4-methylphenyl groups, with respect to the thiono S atom across the thiourea C—N bonds. The dihedral angle between the two groups is 10.36 (8)°. The structure is stabilized by intermolecular hydrogen bonds which form dimers. There are also intramolecular hydrogen bonds.

scholarly journals Synthesis and isomerism of hydrazones of 2-(5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-ylthio)acetohydrazide

2007 ◽  
Vol 5 (4) ◽  
pp. 996-1006 ◽  
Author(s):  
Zenonas Kuodis ◽  
Albertas Rutavičius ◽  
Algirdas Matijoška ◽  
Olegas Eicher-Lorka
Keyword(s):  
Hydrogen Bond ◽  
Nitrogen Atom ◽  
Hydroxy Group ◽  
Intramolecular Hydrogen Bond ◽  
1H Nmr ◽  
Nmr Spectra ◽  
1H Nmr Spectra ◽  
Imino Group ◽  
Anti Conformer ◽  
Intramolecular Hydrogen

AbstractNew hydrazones of 2-(5-thioxo-4,5-dihydro-1,3,4-thiadiazol-2-ylthio)acetohydrazide have been obtained and the percentages of anti/syn - conformers were determined. Based on the analyses of 1H NMR spectra, it was concluded that for hydrazones obtained from the 2- hydroxybenzaldehydes and 2’-hydroxycetophenones the ratio between the anti-and syn-conformers depends on the strength of intramolecular hydrogen bond (IMHB) between the nitrogen atom of the imino group and the proton of the 2-hydroxy group. It was shown that increase in IMHB strength results in stabilization of the anti-conformer in solution.

scholarly journals Deprotonation of resorcinarenes and novel ammonium salt complexes

2014 ◽  
Vol 70 (a1) ◽  
pp. C678-C678
Author(s):  
Ngong Beyeh ◽  
Arto Valkonen ◽  
Fanfang Pan ◽  
Kari Rissanen
Keyword(s):  
Hydrogen Bonds ◽  
Binding Sites ◽  
Molecular Complexes ◽  
Ammonium Salts ◽  
Hydroxyl Groups ◽  
Binding Modes ◽  
Intermolecular Hydrogen Bonds ◽  
Guest Molecules ◽  
Cone Conformation ◽  
Intramolecular Hydrogen

The bowl shape cavity of resorcinarenes usually stabilized by four intramolecular hydrogen bonds offers an interesting array of binding modes such as C–H...π and cation...π interactions to recognize a variety of guests. The multiple hydroxyl groups can participate in a series of intermolecular hydrogen bonds with guest molecules. This unique cone conformation of resorcinarenes has led to the synthesis of many receptors with convergent arrangement of binding sites suitable for molecular recognition in many applications. Unfunctionalized resorcinarenes are known to easily form molecular complexes with guests of varying shapes and sizes. Amines are very common bases used in many catalytic processes. A good example is the use of amines as bases in the alkylation and acylation of resorcinarenes leading to cavitands, carcerands, hemicarcerands and velcrands. The use of amines in such reactions is to deprotonate the resorcinarene hydroxyl groups, hence facilitating the alkylation and acylation processes. The subsequently protonated ammonium cation then forms interesting supramolecular complexes with the anionic and dianionic resorcinarenes. Furthermore, secondary and tertiary ammonium salts possess hydrogen bond donating -NH2 and -NH respectively and these can further enhance their complexation through intermolecular hydrogen bonds. Here we present our recent examples of supramolecular assemblies resulting from the deprotonation of resorcinarenes by mono- and dibasic amines. Also, our latest supramolecular co-crystals between resorcinarenes as the receptors and a series of secondary and tertiary mono- and diammonium cations are illustrated.

Heterocyclic Tautomerism. II. 4-Acylpyrazolones. X-Ray Crystal Structures of 4-Benzoyl-5-methyl-2-phenylpyrazol-3(2H)-one and 4-Acetoacetyl-3-methyl-1-phenylpyrazol-5-ol

1985 ◽  
Vol 38 (3) ◽  
pp. 401 ◽  
Author(s):  
MJ O'Connell ◽  
CG Ramsay ◽  
PJ Steel
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Room Temperature ◽  
Crystalline Form ◽  
Intermolecular Hydrogen Bonds ◽  
Intramolecular Hydrogen Bonds ◽  
X Ray ◽  
Intramolecular Hydrogen

The colourless crystalline form of the benzoylpyrazolone (2) has molecules with the NH structure (2c) stabilized by intermolecular hydrogen bonds. At room temperature crystals are monoclinic: P21/c, a 13.508(5), b 9.124(4), c 11.451(3)Ǻ, β 90.80(3)°, Z4; the structure was refined to R 0.059, Rw 0.048. The acetoacetylpyrazolone (3) has the OH structure (3c) with two intramolecular hydrogen bonds. At 193 K crystals are triclinic: Pī , a 7.142(2), b 13.704(8), c 14.699(7)Ǻ, α 117.36(3), β 96.87(3), γ 93.73(3)°, Z 4; the structure was refined to R 0.049, Rw 0.054.

scholarly journals (E)-2-Amino-4-(3,3-dimethyl-2-oxobutylidene)-1-[2-(2-hydroxyethoxy)ethyl]-6-methyl-1,4-dihydropyridine-3-carbonitrile

2012 ◽  
Vol 68 (8) ◽  
pp. o2572-o2572
Author(s):  
Hyung Jin Kim ◽  
Young Hyun Kim ◽  
Enkhzul Otgonbaatar ◽  
Chee-Hun Kwak
Keyword(s):  
Hydrogen Bonds ◽  
Hydroxy Group ◽  
Title Compound ◽  
Zigzag Chain ◽  
Intramolecular Hydrogen Bonds ◽  
Π Interactions ◽  
Compound C ◽  
Intramolecular Hydrogen ◽  
Dihydropyridine Ring

In the title compound, C17H25N3O3, there are intramolecular hydrogen bonds between an amine H atom and the epoxy O atom, and between a dihydropyridine ring H atom and the ketone O atom. In the crystal, molecules are linked into a zigzag chain running parallel to thecaxis by hydrogen bonds between the hydroxy group and the ketone O atom. There are also weak C—H...O and C—H...π interactions which link the molecules into sheets lying in thebcplane.

scholarly journals Di-μ-chlorido-bis[chlorido(dimethylformamide-κN)(3,5-diphenyl-1H-pyrazole-κN2)copper(II)]

IUCrData ◽  
2018 ◽  
Vol 3 (8) ◽  
Author(s):  
Mercedes S. Naugle ◽  
Brittany T. Keller ◽  
Matthias Zeller ◽  
Curtis M. Zaleski
Keyword(s):  
Hydrogen Bonds ◽  
Pyrazole Ring ◽  
Chloride Anion ◽  
Monoclinic Space Group ◽  
Intermolecular Hydrogen Bonds ◽  
Coordination Environment ◽  
Pyramidal Geometry ◽  
Intramolecular Hydrogen ◽  
Square Pyramidal Geometry ◽  
Fourth Position

The title compound, [Cu2Cl4(C15H12N2)2(C3H7NO)2], Cu2(μ-Cl)2Cl2(3,5-diphenyl-1H-pyrazole)2(DMF)2, where DMF isN,N-dimethylformamide, crystallizes in the monoclinic space groupP21/n. The five-coordinate CuIIions have a distorted square-pyramidal geometry and are joinedviatwo μ-Cl anions. The coordination environment of each CuIIion is completed by a terminal chloride anion, a nitrogen-coordinated 3,5-diphenyl-1H-pyrazole molecule, and a DMF molecule. Two intramolecular hydrogen bonds exist in the molecule as the H atom of the protonated N atom of the 3,5-diphenyl-1H-pyrazole bonds to a terminal chloride anion of the adjacent CuIIcation. In addition, molecules are linked into a two-dimensional sheetviaweak C—H...Cl intermolecular hydrogen bonds. Each dimer hydrogen bonds to four neighboring molecules as the H atom of the C atom in the fourth position of the pyrazole ring bonds to a μ-Cl on a neighboring molecule.

scholarly journals N-[2-(Methylsulfanyl)phenyl]-2-sulfanylbenzamide

2012 ◽  
Vol 68 (8) ◽  
pp. o2400-o2400
Author(s):  
Chang-Chih Hsieh ◽  
Hon Man Lee ◽  
Yih-Chern Horng
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Title Compound ◽  
Aromatic Rings ◽  
Intermolecular Hydrogen Bonds ◽  
Methyl Group ◽  
Interplanar Angle ◽  
Compound C ◽  
Intramolecular Hydrogen

In the title compound, C14H13NOS2, the S atom with the methyl group is involved in an intramolecular hydrogen bond with the amido H atom. In the crystal, the sulfanyl H atoms form intermolecular hydrogen bonds with the O atoms, connecting the molecules into zigzag chains along thecaxis. The two aromatic rings exhibit a small interplanar angle of 16.03 (9)°.

Ethyl 1-[5-amino-1-tert-butyl-3-(methylsulfanyl)-1H-pyrazole-4-carbonyl]-5-methyl-3-(methylsulfanyl)-1H-pyrazole-4-carboxylate

2006 ◽  
Vol 62 (5) ◽  
pp. o1679-o1681
Author(s):  
Jun-Fei Li ◽  
Hai-Bin Song ◽  
You-Quan Zhu ◽  
Hua-Zheng Yang
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Intramolecular Hydrogen Bond ◽  
Membered Ring ◽  
Intermolecular Hydrogen Bonds ◽  
Tert Butyl ◽  
The Family ◽  
Title Molecule ◽  
Intramolecular Hydrogen

The title molecule, C17H25N5O3S2, belongs to the family of bis-heterocycles. In the crystal structure, there are one intra- and two intermolecular hydrogen bonds. One of the two pyrazole rings and the six-membered ring formed by the intramolecular hydrogen bond are approximately coplanar.

Structure and hydrogen bonding in 2,4-dihydroxybenzoic acid at 90, 100, 110 and 150 K; a theoretical and single-crystal X-ray diffraction study

2007 ◽  
Vol 63 (2) ◽  
pp. 303-308 ◽  
Author(s):  
Andrew Parkin ◽  
Martin Adam ◽  
Richard I. Cooper ◽  
Derek S. Middlemiss ◽  
Chick C. Wilson
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Hydrogen Bonds ◽  
X Ray Diffraction ◽  
Dihydroxybenzoic Acid ◽  
X Ray ◽  
Hydrogen Bond System ◽  
Proton Disorder ◽  
Intramolecular Hydrogen ◽  
Carboxylic Acid Dimer

A new polymorph of 2,4-dihydroxybenzoic acid is reported. The structure was characterized by multiple-temperature X-ray diffraction and solid-state DFT computations. The material shows a geometric pattern of hydrogen bonding consistent with cooperativity between the intermolecular carboxylic acid dimer and intramolecular hydrogen bonds. The presence of proton disorder within this hydrogen-bond system, which would support such a cooperative model, was not fully ruled out by the initial X-ray studies. However, solid-state calculations on the three possible end-point tautomers indicate that the dominant crystallographically observed configuration is substantially lower in energy than the other tautomers (by at least 9 kJ mol−1), indicating that no disorder should be expected. It is therefore concluded that no disorder is observed either in the intra- or intermolecular hydrogen bonds of the title compound and that the cooperativity between the hydrogen bonds is not present within the temperature range studied.

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