scholarly journals Solution size variation of linear and dendritic bis-MPA analogs using DOSY-1H NMR

2021 ◽  
Author(s):  
Oluwapelumi O. Kareem ◽  
Farzin Rahmani ◽  
Jason A. Hyman ◽  
Christopher B. Keller ◽  
Melissa A. Pasquinelli ◽  
...  
Keyword(s):  
1H Nmr ◽  
Size Variation ◽  
H Nmr ◽  
Linear Analog ◽  
Size Variability ◽  
First Time

The size and size variability of bis-MPA dendrimers is shown to be smaller by DOSY-1H NMR than their linear analog, PBBM. This was accomplished using five different solvents and for the first time confirms, experimentally, what has been theorized.

scholarly journals Nachweis der Atropisomerie peri-substituierter Naphthalin-Derivate durch dynamische 1H-NMR-Spektroskopie / Dynamic 1H-NMR-Spectroscopic Evidence for the Atropisomerism of Perisubstituted Naphthalene Derivatives

1977 ◽  
Vol 32 (8) ◽  
pp. 912-933 ◽  
Author(s):  
Reiner Luckenbach ◽  
Axel Jensen
Keyword(s):  
1H Nmr ◽  
Chiral Molecules ◽  
Kcal Mole ◽  
Naphthalene Derivatives ◽  
Spectral Parameters ◽  
Hindered Rotation ◽  
H Nmr ◽  
Environment Temperature ◽  
Dynamic 1H Nmr ◽  
First Time

The preparation of the perisubstituted naphthalene derivatives 1-8 is described for the first time, and possible axial or axial and planar chirality of these compounds is investigated by means of dynamic 1H NMR spectroscopy. Molecular chirality, caused by hindered rotation, can be proven for compounds 1 and 3 at room temperature and for 2 at 193 K by the observation of magnetic inequivalence of isochronous protons in a diastereotopic environment. Temperature-dependent 1H NMR spectra indicate that for 2 the coalescence temperature lies between 193 K and 213 K, and above 320 K for 3. By assuming Tcoal- = 200 K for 2 and Tcoal. > 320 K for 3 the following ⊿G≠-values were estimated with the aid of known approximations from the 1H NMR spectral parameters Δν = νA-νB and JAB for the methylene and methyl groups of the oxazoline system present in these species: ⊿G≠ (2) = 10.1 kcal/mole (at 200 K), ⊿G≠ (3) = 17.3 (16.2) kcal/mole (at 320 K). These ⊿G≠-values represent the energy barriers of a dynamic intramolecular process, presumably according to a more or less hindered rotation in the purely axially chiral molecules 2 and 3. With the aid of these ⊿G≠-values and model considerations a description of the energy profile diagram of the hindered rotation in compounds 2 and 8 is attempted.

Mobility of liquids intercalated into the interplane space of graphite oxide as revealed by a combination of 19F NMR, 1H NMR and EPR spin probe methods

2020 ◽  
Vol 22 (35) ◽  
pp. 19969-19974
Author(s):  
Natalia A. Chumakova ◽  
Yaroslav V. Tkachev ◽  
Andrey Kh. Vorobiev ◽  
Anastasya T. Rebrikova ◽  
Mikhail V. Korobov
Keyword(s):  
1H Nmr ◽  
Graphite Oxide ◽  
Spin Probe ◽  
Pulse Sequence ◽  
19F Nmr ◽  
H Nmr ◽  
First Time

A combination of 19F and 1H NMR with the Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence was used to examine the mobility of liquids in the interplane space of graphite oxide (GO) for the first time.

Toxicity assessment of Arisaematis Rhizoma in rats by a 1H NMR-based metabolomics approach

2015 ◽  
Vol 11 (2) ◽  
pp. 407-417 ◽  
Author(s):  
Ge Dong ◽  
Junsong Wang ◽  
Pingping Guo ◽  
Dandan Wei ◽  
Minghua Yang ◽  
...  
Keyword(s):  
1H Nmr ◽  
Histopathological Examination ◽  
Serum Biochemistry ◽  
Toxicity Assessment ◽  
H Nmr ◽  
First Time

A 1H NMR based metabolomics approach combined with serum biochemistry and histopathological examination was used to study the toxicity of Arisaematis Rhizoma by intragastrical administration for the first time.

Conformational study on ribonucleoside O-phosphonylmethyl derivatives by 1H NMR spectroscopy

1985 ◽  
Vol 50 (8) ◽  
pp. 1899-1905 ◽  
Author(s):  
Milena Masojídková ◽  
Jaroslav Zajíček ◽  
Miloš Buděšínský ◽  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Conformational Study ◽  
H Nmr ◽  
Conformational Properties

Conformational properties of ribonucleoside 5'-O-phosphonylmethyl derivatives have been determined by 1H NMR spectroscopy and compared with those of natural nucleosides and 5'-nucleotides.

119Sn, 13C and 1H NMR Spectra of Tris(1-butyl)stannyl D-Glucuronate

1997 ◽  
Vol 62 (8) ◽  
pp. 1169-1176 ◽  
Author(s):  
Antonín Lyčka ◽  
Jaroslav Holeček ◽  
David Micák
Keyword(s):  
Chemical Shift ◽  
Carbonyl Group ◽  
1H Nmr ◽  
Equatorial Plane ◽  
Title Compound ◽  
Nmr Spectra ◽  
Hydroxyl Groups ◽  
Carboxylic Group ◽  
H Nmr ◽  
Oxygen Atoms

The 119Sn, 13C and 1H NMR spectra of tris(1-butyl)stannyl D-glucuronate have been measured in hexadeuteriodimethyl sulfoxide, tetradeuteriomethanol and deuteriochloroform. The chemical shift values have been assigned unambiguously with the help of H,H-COSY, TOCSY, H,C-COSY and 1H-13C HMQC-RELAY. From the analysis of parameters of 119Sn, 13C and 1H NMR spectra of the title compound and their comparison with the corresponding spectra of tris(1-butyl)stannyl acetate and other carboxylates it follows that in solutions of non-coordinating solvents (deuteriochloroform) the title compound is present in the form of more or less isolated individual molecules with pseudotetrahedral environment around the central tin atom and with monodentately bound carboxylic group. The interaction of tin atom with oxygen atoms of carbonyl group and hydroxyl groups of the saccharide residue - if they are present at all - are very weak. In solutions in coordinating solvents (hexadeuteriodimethyl sulfoxide or tetradeuteriomethanol), the title compound forms complexes with one molecule of the solvent. Particles of these complexes have a shape of trigonal bipyramid with the 1-butyl substituents in equatorial plane and the oxygen atoms of monodentate carboxylic group and coordinating solvent in axial positions.

A 15N, 13C, and 1H NMR study of reaction products from arylguanidines and chloroformate esters

1991 ◽  
Vol 56 (7) ◽  
pp. 1505-1511 ◽  
Author(s):  
Antonín Lyčka ◽  
Karel Palát
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Reaction Products ◽  
H Nmr ◽  
Nmr Study

The 15N, 13C, and 1H NMR spectra of the reaction products from arylguanidines with two mols of chloroformate esters have been measured. With application of the corresponding 15N isotopomer it has been proved that the reaction products have the structures IIIa-IIIc.

Synthesis and characterization of novel chiral derivatizing agents containing β-keto-anthracene adducts (KAAs) by 1H-NMR: aromatic influence and chiral alcohol absolute configuration determination

2019 ◽  
Vol 17 (3) ◽  
pp. 541-554
Author(s):  
Neeranuth Intakaew ◽  
Puracheth Rithchumpon ◽  
Chanatkran Prommin ◽  
Saranphong Yimklan ◽  
Nawee Kungwan ◽  
...  
Keyword(s):  
1H Nmr ◽  
Absolute Configuration ◽  
Synthesis And Characterization ◽  
Chiral Alcohols ◽  
Chiral Alcohol ◽  
Aromatic Rings ◽  
H Nmr ◽  
Chiral Derivatizing Agents

New chiral derivatizing agents and the effect of aromatic rings were investigated for absolute configuration of chiral alcohols via1H-NMR.

Different submicellar solubilization mechanisms revealed by 1H NMR and 2D diffusion ordered spectroscopy (DOSY)

2020 ◽  
Vol 22 (19) ◽  
pp. 11075-11085
Author(s):  
Mengjian Wu ◽  
Zhaoxia Wu ◽  
Shangwu Ding ◽  
Zhong Chen ◽  
Xiaohong Cui
Keyword(s):  
Nmr Spectroscopy ◽  
Sodium Dodecyl Sulfate ◽  
1H Nmr ◽  
Sodium Dodecyl ◽  
Butyl Methacrylate ◽  
H Nmr ◽  
Molecular Scale ◽  
Two Systems ◽  
Dodecyl Sulfate ◽  
Triton X

Different submicellar solubilization mechanisms of two systems, Triton X-100/tetradecane and sodium dodecyl sulfate (SDS)/butyl methacrylate, are revealed on the molecular scale by 1H NMR spectroscopy and 2D diffusion ordered spectroscopy (DOSY).

scholarly journals 13C and 1H NMR Spectra of Synthetic (25R)-5α-Spirostanes

1999 ◽  
Vol 23 (1) ◽  
pp. 48-49
Author(s):  
Martín A. Iglesias Arteaga ◽  
Carlos S. Pérez Martinez ◽  
Roxana Pérez Gil ◽  
Francisco Coll Manchado
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr ◽  
C 23 ◽  
Main Effects ◽  
Nmr Signals

The assignment of 13C and 1H NMR signals of synthetic (25 R)-5α-spirostanes is presented; the main effects on chemical shifts due to substitution at C-23 are briefly discussed.

Synthesis and characterization of meso-to-meso directly linked porphyrin-diazaporphyrin triads

2018 ◽  
Vol 22 (09n10) ◽  
pp. 814-820
Author(s):  
Yingying Jia ◽  
Ling Xu ◽  
Bangshao Yin ◽  
Mingbo Zhou ◽  
Jianxin Song
Keyword(s):  
Nickel Complex ◽  
High Resolution Mass Spectrometry ◽  
Dihedral Angles ◽  
X Ray Diffraction ◽  
Extinction Coefficients ◽  
X Ray ◽  
H Nmr ◽  
First Time ◽  
Molar Extinction Coefficients

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.

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