scholarly journals The Cucurbit[8]uril effect on the properties of Oroxin A

2020 ◽  
Author(s):  
Zhishu Zeng ◽  
Jun Xie ◽  
Guangyan Luo ◽  
Zhu Tao ◽  
Qianjun Zhang
Keyword(s):  
Ir Spectroscopy ◽  
Antioxidant Capacity ◽  
Gastric Juice ◽  
Binding Constant ◽  
Inclusion Compound ◽  
Molar Ratio ◽  
Cumulative Release ◽  
H Nmr

In this study, we investigated host–guest interactions between Oroxin A (OA) and cucurbit[8]uril (Q[8]) using 1H NMR, MS, UV-Vis and IR spectroscopy. The results showed that OA and Q[8] formed an inclusion compound (OA@Q[8]) with a molar ratio of 1:1 and a binding constant of 1.299 × 107 L·mol−1. In addition, the effect of Q[8] on the properties of OA was investigated through comparative experiments. The solubility of OA in water increased 22.47-fold when the concentration of Q[8] was 1 × 10−4 mol·L−1. Q[8] hardly affected the antioxidant capacity of OA, while the cumulative release of OA in gastric juice increased 2.3-fold after forming the inclusion compound with Q[8].

scholarly journals Host–guest interaction of cucurbit[8]uril with oroxin A and its effect on the properties of oroxin A

2020 ◽  
Vol 16 ◽  
pp. 2332-2337
Author(s):  
Zhishu Zeng ◽  
Jun Xie ◽  
Guangyan Luo ◽  
Zhu Tao ◽  
Qianjun Zhang
Keyword(s):  
Ir Spectroscopy ◽  
Antioxidant Capacity ◽  
Gastric Juice ◽  
Binding Constant ◽  
Inclusion Compound ◽  
Molar Ratio ◽  
Cumulative Release ◽  
H Nmr

In this study, we investigated the host–guest interactions between oroxin A (OA) and cucurbit[8]uril (Q[8]) using 1H NMR, MS, UV–vis and IR spectroscopy. The results showed that OA and Q[8] formed an inclusion compound (OA@Q[8]) with a molar ratio of 1:1 and a binding constant of 1.299 × 107 L·mol−1. In addition, the effect of Q[8] on the properties of OA was investigated through comparative experiments. The solubility of OA in water increased 22.47-fold when the concentration of Q[8] was 1 × 10−4 mol·L−1. Q[8] hardly affected the antioxidant capacity of OA, while the cumulative release of OA in gastric juice increased 2.3-fold after forming the inclusion compound with Q[8].

scholarly journals A new benzothiazin-functionalized calix[4]arene-based fluorescent chemosensor for the selective and sensitive detection of Co2+ ion

2021 ◽  
Author(s):  
Fatimah Fateh ◽  
Ayşe Yildirim ◽  
Asif Ali Bhatti ◽  
Mustafa YILMAZ
Keyword(s):  
Organic Chemistry ◽  
Detection Limit ◽  
Ir Spectroscopy ◽  
Binding Constant ◽  
Spectroscopic Methods ◽  
Macrocyclic Compounds ◽  
H Nmr ◽  
Ft Ir ◽  
Ft Ir Spectroscopy ◽  
C Nmr

Abstract Calixarenes, which have a great place in supramolecular chemistry, has become the most prominent macrocyclic compounds in synthetic organic chemistry due to their easy synthesis and functionalization. In this study, p-tert-butyl calix[4]arene dihydrazide derivative was synthesized and then reacted with 3-oxo-3,4-dihydro-2H-benzo[b][1, 4] thiazin-2-ylideneacetyl chloride to prepare new calixarene based chromophore compound 4. The structure of the synthesized compound was elucidated by spectroscopic methods such as 1H-NMR 13C-NMR and FT-IR spectroscopy. Chromogenic and fluorescence properties of compound 4 were evaluated. It was observed from both studies that compound 4 was Co2+ selective and shows fluorescence Switched-off behavior. Stoichiometry, binding constant and the detection limit was calculated. The stoichiometry between compound 4 and Co2+ was found to be 1:1. The binding constant value (K) was calculated as 666.67 M− 1 using Benesi–Hildebrand equation, while the detection limit for Co2+ ion was calculated as 0.0465 µM.

Potentiometric titration study of two novel polydenate ligands and investigations of their complexes

2001 ◽  
Vol 79 (4) ◽  
pp. 455-460 ◽  
Author(s):  
Dengke Cao ◽  
Hua-Kuan Lin ◽  
Zhi-Fen Zhou ◽  
Shou-Rong Zhu ◽  
Xun-Cheng Su ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Metal Complex ◽  
Metal Complexes ◽  
Molar Ratio ◽  
Complex Stability ◽  
Binding Ability ◽  
H Nmr ◽  
Binuclear Metal ◽  
The Stability ◽  
Titration Study

Two novel linear polyamine ligands, N,N'-bis-(2-(N''-2-hydroxyl-5-bromobenzyl)aminoethyl) malondiamide (L1) and N,N'-bis-(3-(N''-2-hydroxyl-5-bromobenzyl)aminopropyl) malondiamide (L2), have been synthesized and fully characterized by elemental analysis (1H NMR and IR spectroscopy) (Fig. 1). The binding ability of ligands L1 and L2 to metal ions such as Cu(II), Zn(II), Co(II), Mn(II), Mg(II), and Ca(II) has been investigated by the potentiometric method in 1,4-dioxane–water (v/v = 15:100) and KNO3 (0.1 mol dm–3) at 25.0°C. In view of the linear structures of L1 and L2, binuclear metal complexes can be formed in solution by controlling Cu(II)-5-substituted o-phenanthroline (Rphen, R = CH3, H, Cl, NO2):L to a 2:1 molar ratio, whereas the mononuclear metal complexes form at molar ratio M(II):L of 1:1, where M(II) is Cu(II), Zn(II), Co(II), Mn(II), Mg(II), and Ca(II). The stability constants of metal complexes have been determined and further discussed. In addition, two manganic complexes have been synthesized and IR and electronic spectra showed their coordination nature.Key words: linear polyamine ligand, 5-substituted o-phenanthroline, mononuclear and binuclear metal complex, stability, spectrum.

scholarly journals Synthesis, Characterization, and Electrochemical Behaviour of Cobalt(II) and Nickel(II) Complexes with N2O2 Chelating Ligand 4,4′-(Biphenyl-4,4′-diyldinitrilo)dipentan-2-one

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Lakhdar Sibous ◽  
Embarek Bentouhami ◽  
Mustayeen Ahmed Khan
Keyword(s):  
Schiff Base ◽  
Mass Spectroscopy ◽  
Elemental Analysis ◽  
Electrochemical Behaviour ◽  
Absolute Ethanol ◽  
Molar Ratio ◽  
H Nmr ◽  
Chelating Ligand ◽  
Metal Ligand

4,4′-Diaminobiphenyl reacts with 2,4-pentanedione in absolute ethanol in a molar ratio 1 : 2 to form mainly the product of [1 + 2] condensation, 4,4′-(biphenyl-4,4′-diyldinitrilo)dipentan-2-one (H2L). The Schiff base was used as tetradentate chelating ligand to coordinate CoII and NiII chlorides leading to complexes where the ratio of metal ligand was found to be 2 : 1 or 2 : 2. All the synthesized products were characterized by elemental analysis, infrared, electronic, and mass spectroscopy, 1H NMR, and DSC. The electrochemical behaviour of the ligand and its complexes in DMF is also investigated.

SILICON-CONTAINING OLIGOMERIC AZOINITIATORS IN THE SYNTHESIS OF BLOCK COPOLYMERS

2021 ◽  
Vol 43 (2) ◽  
pp. 123-132
Author(s):  
N.A. Busko ◽  
◽  
V.K. Grishchenko ◽  
A.V. Barantsova ◽  
N.V. Gudzenko ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Block Copolymers ◽  
Ir Spectroscopy ◽  
Molar Ratio ◽  
Capacity Curves ◽  
Azo Initiator ◽  
Azo Initiators

The aim of the work was to develop methods for the synthesis and study of the properties of silicon-containing oligomeric azo- and polyazoinitiators based on bis-γ-hydroxypropylpolysiloxane (HPS) and bis-γ-aminopropylpolysiloxane (APS). Silicon-containing oligomeric azoinitiators using HPS were synthesized on the basis of cyclohexanone azo-bis-isobutyrohydrazone (AGN-CH) and bis-γ-hydroxypropylpolysiloxane bifunctional macrodiisocyanate (MDIHPS). MDIHPS was obtained by the interaction of GPS with 2,4 toluene diisocyanate (2,4-TDI). Oligomeric azoinitiators have been obtained, which have the structure RXR and (RX)nR, where R is a propylpolysiloxane block, X is a azo initiator block. For the synthesis of an oligomeric azo initiator based on bis-γ-aminopropyl polysiloxane (APS), a method was first developed for the synthesis of a monomeric azo initiator with terminal oxadiazolinylcarbamanate isocyanate groups (AGN-NCO) by the interaction of AGN-CH and 2,4-TDI at a molar ratio of 1: 2. On the basis of the obtained AGN-NCO and APS at a molar ratio of AGN-NCO: APS = 1: 1, an oligomeric azo initiator (OAI APS-P) was synthesized, which has the structure (RX)nR, where R is a propylpolysiloxane block, X is an azo initiator block. The structures of monomeric and oligomeric azo initiators have been studied by UV and IR spectroscopy, and the kinetic regularities of their synthesis have been calculated. On the basis of oligomeric azo initiators and styrene, block copolymers of the (AB)nA type were obtained by the method of thermal and photoinitiated radical polymerization, where A is a propylpolysiloxane block, B is an oligosyrene block with a constant value of the organosilicon block and a different size of the oligostyrene block. The structure of block copolymers was investigated by IR spectroscopy. It was shown that during photopolymerization, oligostyrene blocks of shorter length are formed than during thermopolymerization, and possible oxidation processes. The study of relaxation transitions by DSC in oligostyrene and propylpolysiloxane blocks of the BCP showed that the common heat capacity curves are the presence of two jumps in the heat capacity at the glass transition temperatures of the polysiloxane and oligostyrene microphase. A slight shift in the glass transition temperature of polysiloxane microphases in BCP towards higher temperatures compared to the homopolymer may be associated with the effect of oligostyrene microphase. With a decrease in the length of the oligosyrene block, a low-temperature shift in the glass transition temperature of oligostyrene blocks relative to the homopolymer and a depression of ∆Cp,2 are observed, which is associated with the suppression of mobility in oligodienic microphases by less mobile propylpolysiloxane blocks.

Electrochemically Synthesis and Characterization of Copolymers Based on 1, 4-Diethoxybenzene and 3, 4-Ethylenedioxythiophene

2011 ◽  
Vol 335-336 ◽  
pp. 989-993
Author(s):  
Mi Ouyang ◽  
Zhen Wei Yu ◽  
Yi Xu ◽  
Yu Jian Zhang ◽  
Cheng Zhang
Keyword(s):  
Cyclic Voltammetry ◽  
Ir Spectroscopy ◽  
Feed Ratio ◽  
Synthesis And Characterization ◽  
Monomer Mixture ◽  
Long Wavelength ◽  
H Nmr ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Copolymers based on 1, 4-diethoxybenzene (DEB) and 3, 4-ethylenedioxythiophene (EDOT) were electrochemically synthesized and characterized. The structures of the copolymers were established by 1H NMR and FT-IR spectroscopy. The results indicated the final product was a copolymer instead of a blend or a composite. The physical properties were systematically investigated by cyclic voltammetry, UV-vis absorption and fluorescence. The PL maximum of copolymers presented obviously red-shift to long wavelength as the feed ratio of EDOT in monomer mixture increased.

scholarly journals Linkage of α-cyclodextrin-terminated poly(dimethylsiloxanes) by inclusion of quasi bifunctional ferrocene

2013 ◽  
Vol 9 ◽  
pp. 1278-1284 ◽  
Author(s):  
Helmut Ritter ◽  
Berit Knudsen ◽  
Valerij Durnev
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Light Scattering ◽  
Ir Spectroscopy ◽  
Nmr Spectra ◽  
H Nmr ◽  
Scattering Measurements ◽  
End Groups ◽  
2D Roesy ◽  
2D Roesy Nmr

We report the noncovalent linkage of terminally substituted oligo(dimethylsiloxanes) bearing α-cyclodextrins (α-CD) as host end groups for the cyclopentadienyl rings of ferrocene. This double complexation of unsubstituted ferrocene leads to a supramolecuar formation of the siloxane strands. Structural characterization was performed by the use of 1H NMR and IR spectroscopy and by mass spectrometry. Electron microscopy studies and dynamic light scattering measurements show a significant decrease of the derivative size after the complexation with ferrocene. In addition, further evidence for the successful complexation of the end groups was verified by the shifts of the protons in the 1H NMR spectra and in the correlation signals of the 2D ROESY NMR spectra.

scholarly journals Fliposomes: pH-controlled Release from Liposomes Containing New trans-2-Morpholinocyclohexanol-based Amphiphiles that Perform a Conformational Flip and Trigger an Instant Cargo Release upon Acidification

2012 ◽  
Vol 7 (3) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Yu Zheng ◽  
Xin Liu ◽  
Nataliya M. Samoshina ◽  
Vyacheslav A. Chertkov ◽  
Andreas H. Franz ◽  
...  
Keyword(s):  
Molecular Size ◽  
Ph Sensitive ◽  
Molar Ratio ◽  
Ph Titration ◽  
Conformational Switch ◽  
Liposome Membrane ◽  
H Nmr ◽  
Rapid Release ◽  
New Type ◽  
Plausible Mechanism

A new type of pH-sensitive liposome (fliposomes) was designed based on the amphiphiles that are able to perform a pH-triggered conformational flip (flipids). This flip disrupts the liposome membrane and causes rapid release of the liposome cargo, specifically in the areas of increased acidity. The flipids (1-3) are equipped with a trans-2-morpholinocyclohexanol conformational switch. pH-Sensitive fliposomes containing one of these flipids, POPC and PEG-ceramide (molar ratio 50/45/5) were constructed and characterized. These compositions were stable at 4oC and pH 7.4 for several months. Fliposomes loaded with ANTS/DPX demonstrated an unusually quick content release (in a few seconds) at pH below 5.5, which was more efficient in the case of flipid 1 with the shorter linear C12-tails. The pH-titration curve for the fliposome leakage paralleled the curve for the acid-induced conformational flip of 1-3 studied by 1H NMR. A plausible mechanism of the pH-sensitivity starts with an acid-triggered conformational flip of 1, 2 or 3, which changes the molecular size and shape, shortens the lipid tails, and perturbs the liposome membrane resulting in the content leakage.

Phosphor- und Schwefelhydrazin-Verbindungen / Phosphorus- and Sulfurhydrazine-Compounds

1971 ◽  
Vol 26 (12) ◽  
pp. 1232-1235 ◽  
Author(s):  
Herbert W. Roesky ◽  
Olaf Petersen
Keyword(s):  
Ir Spectra ◽  
Elemental Analysis ◽  
Mass Spectra ◽  
Molar Ratio ◽  
H Nmr ◽  
Chemical Behaviour

Pyrosulfonyldifluoride reacts with waterfree hydrazine in a molar ratio of 2 : 3 to give hydrazine -1,2-bis(sulfonylfluoride) in a low yield.. The reaction of N-fluorosulfonylamide and SOCl2 yields NH4⊕⊖ N(SO2F)2. This salt is converted to (C6H5)4P⊕⊖N(SO2F)2 in water by (C6H5)4PCl. (CH3)2NNH2 reacts with PSF3, PSF2Br, PSF2CH3 or PSF2C2H5 to yield the following compounds: (CH3)2NNHPSF2, (CH3)2NN (PSF2)2, (CH3)2NNHPSFCH3 and (CH3)2NNHPSFC2H5. The properties and the chemical behaviour of these substances are described. Results of ir-spectra, as well as 31P-, 19F- and 1H-nmr- and mass-spectra and elemental analysis characterize the compounds.

Host-guest interactions of cyclodextrins and metalloporphyrins: supramolecular building blocks toward artificial heme proteins

2004 ◽  
Vol 08 (02) ◽  
pp. 125-140 ◽  
Author(s):  
Huchen Zhou ◽  
John T. Groves
Keyword(s):  
Binding Constant ◽  
Molecular Design ◽  
Covalent Binding ◽  
Binding Constants ◽  
Building Blocks ◽  
Binding Pocket ◽  
Axial Ligand ◽  
Pyridyl Nitrogen ◽  
H Nmr ◽  
Self Assembled

Cyclodextrins are versatile building blocks for a variety of macromolecules due to the inclusion complexes that are formed with hydrophobic organic molecules. Cyclodextrin-porphyrin interactions are of particular interest since cyclodextrins can serve as a non-covalent binding pocket while metalloporphyrins could serve as the heme analogs in the construction of heme protein model compounds. Various approaches to the design and assembly of biomimetic porphyrin constructs are compared and contrasted in this minireview with a particular emphasis on self-assembled and porphyrin-cyclodextrin systems. Several recent advances from our laboratories are described in this context. A sensitive fluorescent binding probe, 6A-N-dansyl-permethylated-β-cyclodextrin (Dan-NH-TMCD), was found to form 2:1 complexes with the meso-tetraphenylporphyrins Mn(III)TCPP , Mn(III)TPPS and Mn(III)TF 4 TMAP with high binding constants. A perPEGylated cyclodextrin, heptakis(2,3,6-tri-O-2-(2-(2-methoxyethoxy)ethoxy)ethyl)-β-cyclodextrin (TPCD), has been shown by 1 H NMR spectroscopy to form a 1:1 complex with H 2 TCPP with a binding constant above 108M-1. Such a strong binding constant is the largest found for a 1:1 complex between a monomeric cyclodextrin and a guest. TPCD was also found to bind Mn(III)TCPP with a binding constant of 1.2 × 106 M -1. A novel, self-assembled hemoprotein model, hemodextrin is also described. The molecular design is based on a PEGylated cyclodextrin scaffold that bears both a heme-binding pocket and an axial ligand that binds an iron porphyrin. The binding constant for Fe (III) TPPS (iron(III) meso-tetra(4-sulfonatophenyl)porphyrin) by py-PPCD was determined to be 2 × 106 M -1. The pyridyl nitrogen of py-PPCD was shown to ligate to the iron center by observing signal changes in the Fe(II) -porphyrin 1 H NMR spectrum. This hemodextrin ensemble, a minimalist myoglobin, was shown to bind dioxygen reversibly and to form a stable ferryl species.

Sign in / Sign up

Export Citation Format

Share Document