GIAO-DFT calculated and experimentally derived complexation-induced chemical shifts of calix[4]arene–solvent inclusion complexesElectronic supplementary information (ESI) available: calculated and observed NMR data and geometrical details for complexes 1–3, 1–4 and 1–5. See http://www.rsc.org/suppdata/p2/b1/b110078p/

2002 ◽  
pp. 484-488 ◽  
Author(s):  
Alexander Christian Backes ◽  
Jürgen Schatz ◽  
Hans-Ullrich Siehl
Keyword(s):  
Chemical Shifts ◽  
Supplementary Information ◽  
Nmr Data

scholarly journals Real-time prediction of 1H and 13C chemical shifts with DFT accuracy using a 3D graph neural network

2021 ◽  
Author(s):  
Yanfei Guan ◽  
S. V. Shree Sowndarya ◽  
Liliana C. Gallegos ◽  
Peter C. St. John ◽  
Robert S. Paton
Keyword(s):  
Neural Network ◽  
Real Time ◽  
Quantum Chemical ◽  
Organic Molecules ◽  
Chemical Shifts ◽  
13C Chemical Shifts ◽  
Time Prediction ◽  
Nmr Data ◽  
Proton Chemical Shifts

From quantum chemical and experimental NMR data, a 3D graph neural network, CASCADE, has been developed to predict carbon and proton chemical shifts. Stereoisomers and conformers of organic molecules can be correctly distinguished.

A Pyoverdin from the Antarctica Strain 51W of Pseudomonas fluorescens

1999 ◽  
Vol 54 (3-4) ◽  
pp. 156-162 ◽  
Author(s):  
Jessica Voss ◽  
Kambiz Taraz ◽  
Herbert Budzikiewicz
Keyword(s):  
Amino Acids ◽  
Pseudomonas Fluorescens ◽  
Binding Sites ◽  
Chemical Shifts ◽  
Chemical Degradation ◽  
Spectroscopic Methods ◽  
Extreme Conditions ◽  
Structural Elements ◽  
Nmr Data ◽  
Schirmacher Oasis

From the strain 51W of Pseudomonas fluorescens living under extreme conditions at the Schirmacher Oasis (Antarctica) a pyoverdin was obtained. Its structure was elucidated by chemical degradation and spectroscopic methods. The NMR data of the pyoverdin and of its Ga(III) complex were compared. Appreciable influences of the metal on the chemical shifts of the atoms at its binding sites were observed. Thus the structural elements involved in the complexation can be identified and coinciding signals of amino acids occurring more than once in the peptide chain can be separated.

scholarly journals 29Si NMR Chemical Shifts in Crystalline and Amorphous Silicon Nitrides

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1646 ◽  
Author(s):  
Ilia Ponomarev ◽  
Peter Kroll
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Density Functional ◽  
Chemical Shifts ◽  
29Si Nmr ◽  
Hydrogenated Silicon ◽  
Nmr Chemical Shifts ◽  
Nmr Data ◽  
29Si Nmr Spectra ◽  
The Impact

We investigate 29Si nuclear magnetic resonance (NMR) chemical shifts, δiso, of silicon nitride. Our goal is to relate the local structure to the NMR signal and, thus, provide the means to extract more information from the experimental 29Si NMR spectra in this family of compounds. We apply structural modeling and the gauge-included projector augmented wave (GIPAW) method within density functional theory (DFT) calculations. Our models comprise known and hypothetical crystalline Si3N4, as well as amorphous Si3N4 structures. We find good agreement with available experimental 29Si NMR data for tetrahedral Si[4] and octahedral Si[6] in crystalline Si3N4, predict the chemical shift of a trigonal-bipyramidal Si[5] to be about −120 ppm, and quantify the impact of Si-N bond lengths on 29Si δiso. We show through computations that experimental 29Si NMR data indicates that silicon dicarbodiimide, Si(NCN)2 exhibits bent Si-N-C units with angles of about 143° in its structure. A detailed investigation of amorphous silicon nitride shows that an observed peak asymmetry relates to the proximity of a fifth N neighbor in non-bonding distance between 2.5 and 2.8 Å to Si. We reveal the impact of both Si-N(H)-Si bond angle and Si-N bond length on 29Si δiso in hydrogenated silicon nitride structure, silicon diimide Si(NH)2.

NMR-spektroskopische Untersuchungen an 1,1-Thiophendioxid und verwandten Verbindungen / NMR Spectroscopical Investigations of Thiophene 1,1-Dioxide and Related Compounds

1984 ◽  
Vol 39 (7) ◽  
pp. 915-920 ◽  
Author(s):  
Herbert Meier ◽  
Thomas Molz ◽  
Heinz Kolshorn
Keyword(s):  
Computer Simulation ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Multiple Resonance ◽  
Nmr Data ◽  
Cyclic Diene ◽  
Related Compounds ◽  
C Nmr

The 1H and 13C NMR data of thiophene 1,1-dioxide (3) and related compounds, especially of the precursor 2 and the consecutive product 5 are evaluated by computer simulation and multiple resonance. Chemical shifts and coupling constants reveal that 3 has the character of a cyclic diene. Diatropic or paratropic effects can be excluded.

scholarly journals Исследование строения, ионной, молекулярной подвижности и термических свойств гидратов пентафторидоцирконата аммония

2019 ◽  
Vol 126 (2) ◽  
pp. 147
Author(s):  
Е.И. Войт ◽  
А.Б. Слободюк ◽  
Н.А. Диденко
Keyword(s):  
Structural Changes ◽  
Chemical Shifts ◽  
Molecular State ◽  
Structural Motif ◽  
Nmr Data ◽  
State Of Water ◽  
Hydrate Number ◽  
Bond Strengths ◽  
Isotropic Chemical Shifts ◽  
Ir And Raman

AbstractThe effect of hydrate number on the structural changes, thermal properties, and ionic (molecular) mobility character in NH_4ZrF_5 ⋅ H_2O, NH_4ZrF_5 ⋅ 0.75H_2O crystal hydrates have been investigated by the methods of IR, Raman, nuclear magnetic resonance (NMR) (^1H, ^19F, including ^19F MAS), and TG-DTA spectroscopy. Differences in crystal hydrate structures—anion structure, molecular state of water, and O–H⋅⋅⋅F, N–H⋅⋅⋅F hydrogen bond strengths—have been corroborated by IR and Raman spectroscopy data. Isotropic chemical shifts of magnetic inequivalent positions have been determined and attributed to crystal structures of the studied compounds by the method of ^19F MAS NMR. It has been established that the removal of water molecules from NH_4ZrF_5 ⋅ H_2O and NH_4ZrF_5 ⋅ 0.75H_2O results in the transformation of chain or layered structures accompanied by the increase of the number of bridge bonds while retaining or increasing the dimensionality of the anion structural motif. According to the ^1H NMR data, the NH $$_{4}^{ + }$$ cation diffusion in NH_4ZrF_5 occurs only in the temperature range of 370–520 K.

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