scholarly journals Synthesis of Cr(III)-Morin Complex: Characterization and Antioxidant Study

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qadeer K. Panhwar ◽  
Shahabuddin Memon
Keyword(s):  
Metal Ion ◽  
Bathochromic Shift ◽  
Peak Shift ◽  
Ring System ◽  
Water Molecules ◽  
Nmr Studies ◽  
H Nmr ◽  
Crystalline Water ◽  
Complex Characterization ◽  
Stable Ring

The complex formation between Cr(III) and morin was carried out in methanol and confirmed by analytical characterization using UV-Vis, IR,1H NMR, and TG-DTA. UV-Vis shows significant bathochromic shift in benzoyl upon coordination as well as IR well illustrates the peak shift of C=O group and formation of a O–Cr(III) bond. Likewise,1H NMR studies clarify that Cr(III) metal ion replaces the 5OH proton hence; 5-hydroxy-4-keto site is employed by morin in chelation to form six-membered stable ring system out of three available chelating sites. In addition, TG-DTA denotes the presence of coordinated and crystalline water molecules. The melting point of the complex was found to be 389°C by DSC. In addition, Cr(III)-morin complex was found to be a more potent antioxidant than morin as evaluated by DPPH• and FRAP methods.

NMR Studies on Motion of Crystalline Water Molecules in K2Pt (CN)4Br0.3·3.2H2O

1982 ◽  
Vol 51 (8) ◽  
pp. 2470-2477 ◽  
Author(s):  
Haruo Niki ◽  
Hideyuki Doi ◽  
Hiroshi Nagasawa
Keyword(s):  
Water Molecules ◽  
Nmr Studies ◽  
Crystalline Water

scholarly journals NMR Studies on Dynamics of Water Intercalated in Clay Minerals

1999 ◽  
Vol 54 (6-7) ◽  
pp. 431-436 ◽  
Author(s):  
Shin’ichi Ishimaru ◽  
Ryuichi Ikeda
Keyword(s):  
Nmr Spectra ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Axial Rotation ◽  
Spin Lattice Relaxation ◽  
Water Molecules ◽  
Nmr Studies ◽  
Spin Lattice ◽  
H Nmr ◽  
Clay Layers

Abstract The dynamics of water molecules intercalated in D2O saturated synthetic and natural smectites, and a synthetic Na-fluormica were studied by measurements of solid state 2H NMR spectra and spin-lattice relaxation times at 150 - 370 K. The obtained results could be explained by the 2-site flip, the C2 rotation and the isotropic rotation of the D2O molecules in smectites. In fluormica, the isotropic motion was undetectable, but the axial rotation of the hydration sphere as a whole was observed. The activation energies and correlation times of the C2 rotation were almost independent of the interlayer cations but depended on the character of clay-layers.

Self-assembled supramolecular triad composed of fulleropyrrolidine bearing two pyridine moieties axially coordinated to two zinc porphyrins

2003 ◽  
Vol 07 (01) ◽  
pp. 1-7 ◽  
Author(s):  
Mohamed E. El-Khouly ◽  
Suresh Gadde ◽  
Gollapalli R. Deviprasad ◽  
Mamoru Fujitsuka ◽  
Osamu Ito ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Metal Ion ◽  
Spectral Studies ◽  
Central Metal ◽  
Nmr Studies ◽  
Axial Coordination ◽  
H Nmr ◽  
Zinc Porphyrins ◽  
Self Assembled

Spectroscopic, redox, and photochemical behavior of a self-assembled donor-acceptor triad formed by axial coordination of zinc meso-tetraphenylporphyrin, Zn ( TPP ) with fulleropyrrolidine bearing two pyridine moieties ( C 60( Py )2) was investigated. The UV-visible and 1 H NMR spectral studies revealed supramolecular 1:2 triad formation between C 60( Py )2 and Zn ( TPP ). The determined overall formation constant, K was as large as 1.45 × 104 mol -2 in o-dichlorobenzene (o-DCB). The 1 H NMR studies revealed axial coordination of both the pyridine entities of C 60( Py )2 to the central metal ion of the zinc porphyrins. Electrochemical studies of the isolated self-assembled triad in o-DCB established the molecular stoichiometry of the supramolecular complex possessing one C 60( Py )2 and two Zn ( TPP ) entities. The excited state electron transfer reactions were monitored by both steady-state emission as well as transient absorption techniques. In o-DCB, upon coordination of the pyridine entities of C 60( Py )2 to two Zn ( TPP ), the main quenching pathway involved charge-separation from the singlet excited Zn ( TPP ) to the C 60 moiety. However, in a coordinating solvent like PhCN , intermolecular electron-transfer takes place from the triplet excited state of Zn ( TPP ) to the C 60 moiety.

scholarly journals Crystal structure of (E)-2-(2-{5-[(2-acetoxyethyl)(methyl)amino]thiophen-2-yl}vinyl)-3-methylbenzothiazolium iodide monohydrate

2014 ◽  
Vol 70 (10) ◽  
pp. o1104-o1105
Author(s):  
Xian-Shun Sun ◽  
Ming-Ming Wang ◽  
Dan-Dan Li
Keyword(s):  
Crystal Structure ◽  
Thiophene Ring ◽  
Three Dimensional ◽  
Ring System ◽  
Maximum Deviation ◽  
Water Molecules ◽  
Supramolecular Network ◽  
Hydrated Salt ◽  
Centroid Distance ◽  
Crystalline Water

In the cation of the title hydrated salt, C19H21N2O2S2+·I−·H2O, the benzothiazolium ring system is approximately planar [maximum deviation = 0.0251 (15) Å], and it makes a small dihedral angle of 1.16 (18)° with the plane of the thiophene ring. In the crystal, the cations, anions and crystalline water molecules are linked by classical O—H...O, O—H...I and weak C—H...O hydrogn bonds, forming a three-dimensional supramolecular network. π–π stacking is observed between parallel thiazole rings of adjacent cations [centroid–centroid distance = 3.5945 (16) Å].

Verbindungen mit dem 5,6-Benzo-l,3,2-diazaphosphorinan-4-on-Ringsystem: Synthese von 2-Chlor-, 2-N,N-dimethylamino-und 2-Bis-(2-chlorethyl)amino- substituierten Derivaten mit drei-und vierfach koordiniertem Phosphor / Compounds Involving the 5,6-Benzo-l,3,2-diazaphosphorinane-4-one Ring System: Synthesis of 2-Chloro-, 2-N,N-dimethylamino-and 2-Bis-(2-chloroethyl)amino- Substituted Derivatives with Three-and Four-Coordinated Phosphorus

1994 ◽  
Vol 49 (6) ◽  
pp. 788-800 ◽  
Author(s):  
Ralf Sonnenburg ◽  
Ion Neda ◽  
Axel Fischer ◽  
Peter G. Jones ◽  
Reinhard Schmutzler
Keyword(s):  
Nitrogen Atom ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Ring System ◽  
Phosphorus Trichloride ◽  
Amine Hydrochloride ◽  
Nmr Studies ◽  
X Ray ◽  
H Nmr ◽  
Structure Determinations

The reaction of methylisatoic anhydride with 2-(aminomethyl)pyridine, 3-(aminomethyl)- pyridine, 3-dimethylamino-1-propylamine, 3-diethylamino-1-propylamine and 3-dibutylamino- 1-propylamine furnished the N-substituted N'-methylanthranilic amides 1-5. In the reaction of 1-5 with phosphorus trichloride the 3-substituted 5,6-benzo-1-m ethyl-1,3,2-diazaphosphorinane- 4-one derivatives 6 to 10 were obtained. The possibility of intramolecular donoracceptor interaction between the nitrogen atom of the R2N group and the λ3P atom is suggested on the basis of 1H NMR studies. The reaction of 9 with dimethylamino-trimethylsilane furnished the 2-dimethylamino-substituted product 11. In the reaction of 6, 7 and 10 with bis-(2-chloroethyl)amine hydrochloride/triethylamine the expected substitution products 12 to 14 were obtained. 5,6-Benzo-2-[bis-(2-chloroethyl)amino]-1-methyl-3-(3-picolyl)-1,3,2-diazaphosphorinan- 4-one 13 reacted with (COD)PtCl2 to give the czs-dichloro-platinum(II) complex 15. The characterisation of 1-15 is based on the 1H-, 13C-, and 31P-NMR spectra, mass spectra and X-ray structure determinations of the precursor compounds 1 and 3

1H NMR Conformational Studies in Water of Angiotensin II Analogues Modified at the N- and C-Termini: Interactions of the Aromatic Side Chains and Folding of the N-Terminal Domain

1994 ◽  
Vol 59 (11) ◽  
pp. 2523-2532 ◽  
Author(s):  
John Hondrelis ◽  
John Matsoukas ◽  
George Agelis ◽  
Paul Cordopatis ◽  
Ning Zhou ◽  
...  
Keyword(s):  
Shielding Effect ◽  
Resonance Spectroscopy ◽  
Nmr Studies ◽  
Previous Suggestion ◽  
Aminoisobutyric Acid ◽  
H Nmr ◽  
Neutral Ph ◽  
Angiotensin Ii Analogues ◽  
Proton Resonances ◽  
Cosy Nmr

The conformation of [Sar1]angiotensin II in water at neutral pH has been examined by proton magnetic resonance spectroscopy at 400 MHz and in particular by comparing its 1H NMR spectral data with those of analogues modified at positions 1,4 and 6, namely [Sar1,Cha8]ANGII, [Des Asp1,Cha8]ANGII, [Aib1,Tyr(Me)4]ANGII, [Aib1,Tyr(Me)4,Ile8]ANGII, [N-MeAib1,Tyr(Me)4]ANGII, [N-MeAib1,Tyr(Me)4,Ile8]ANGII, ANGIII and [Sar1,Ile8]ANGII. Assignment of all proton resonances in these analogues was made possible by 2D COSY NMR experiments. The H-2 and H-4 protons for the histidine ring in [Sar1]ANGII, ANGII and ANGIII were shielded compared with the same protons in [Sar1,Ile8]ANGII, [Sar1,Cha8]ANGII and [Des Asp1,Cha8]ANGII; this shielding effect was not disturbed upon methylation of the tyrosine hydroxyl and/or replacement of residue 1 (sarcosine or aspartic acid) with aminoisobutyric acid (Aib) or N-methyl aminoisobutyric acid (N-MeAib). These data are consistent with our previous suggestion based on NMR studies in neutral DMSO that a characteristic folded conformation for ANGII previously observed in non-polar solvents can also be detected in water at neutral pH, but to a lesser degree.

scholarly journals A multilevel investigation supported by multivariate analysis for tomato product formulation

2021 ◽  
Author(s):  
Fatma Boukid ◽  
Elena Curti ◽  
Agoura Diantom ◽  
Eleonora Carini ◽  
Elena Vittadini
Keyword(s):  
Thermal Treatment ◽  
Color Change ◽  
Water Molecules ◽  
Thermal Treatments ◽  
Industrial Processing ◽  
H Nmr ◽  
Mobile Populations ◽  
Product Formulation ◽  
Tomato Product ◽  
The Impact

AbstractIndustrial processing of tomato includes its cutting and mincing, thermal treatments, and the addition of ingredients, which might induce changes in physicochemical properties of the final products. In this frame, the impact of texturing/thickening [xanthan gum (X) or potato fiber (F)] on the macroscopic, mesoscopic and molecular properties of tomato double concentrate (TDC) was investigated to determine if F can efficiently substitute X, in association with small solutes (sugar and salt) and thermal treatment (cold and hot). At a macroscopic level, multivariate statistics (MANOVA) underlined that color change (ΔE) was increased by X and F addition contrary to heating and the addition of salt and sugar. MANOVA revealed that texture was greatly enhanced through the use of F over X. 1H NMR molecular mobility changes were more controlled by texturing agents (F and X) than thermal treatment and small solutes. Particularly F increased the more rigid population indicating stronger interaction with water molecules resulting in shear-thinning flow. However, adding X contributed into the increase of the dynamic and mobile populations. Therefore, F can be a valid “clean label” substitute of X in modulating tomato products properties.

High field 1H NMR Studies of Sol-Gel Kinetics

1986 ◽  
Vol 73 ◽  
Author(s):  
Bruce D. Kay ◽  
Roger A. Assink
Keyword(s):  
Equilibrium Distribution ◽  
Sol Gel ◽  
Nmr Studies ◽  
H Nmr ◽  
Rate Limiting Step ◽  
Rate Of Hydrolysis ◽  
Acid Catalyzed ◽  
Product Species ◽  
Rate Limiting ◽  
Kinetics Of

ABSTRACTHigh resolution 1H NMR spectroscopy at high magnetic fields is employed to study the reaction kinetics of the Si(OCH3)4:CH3OH:H2O sol-gel system. Both the overall extent of reaction as a function of time and the equilibrium distribution of species are measured. In acid catalyzed solution, condensation is the rate limiting step while in base catalyzed solution, hydrolysis becomes rate limiting. A kinetic model in which the rate of hydrolysis is assumed to be independent of the adjacent functional groups is presented. This model correctly predicts the distribution of product species during the initial stages of the sol-gel reaction.

Equilibrium thermodynamic studies for the formation of 1:1 complexes of CO and ethene with a rhodium(II) porphyrin metallo-radical

2001 ◽  
Vol 79 (5-6) ◽  
pp. 854-856 ◽  
Author(s):  
Leah Basickes ◽  
Andrew G Bunn ◽  
Bradford B Wayland
Keyword(s):  
Carbon Monoxide ◽  
Complex Formation ◽  
Equilibrium Thermodynamic ◽  
Nmr Studies ◽  
Thermodynamic Studies ◽  
H Nmr ◽  
Porphyrin Ligand ◽  
The One ◽  
Paramagnetic Shifts

Tetra(2,4,6 triisopropropyl phenyl)porphyrinatorhodium(II) ((TTiPP)RhII·1) is a persistent metal-centered radical with the odd electron in the rhodium(II) dz2 orbital. (TTiPP)RhII· forms 1:1 complexes with CO and CH2CH2 where the porphyrin ligand steric properties inhibit further reactions of the one-electron activated substrates. 1H NMR paramagnetic shifts at a series of temperatures are used in evaluating the thermodynamics for CO complex formation with 1 to form [(TTiPP)RhII(CO)]·2 (ΔH° = -5.5 ± 0.5 kcal mol-1; ΔS° = -9 ± 1 cal K-1 mol-1). Related 1H NMR studies show that the bonding of 1 with ethene is less favorable than CO.Key words: rhodium porphyrin, carbon monoxide, ethene, thermodynamics, complex formation, metal-centered radical.

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