scholarly journals NMR parameters of FNNF as a test for coupled-cluster methods: CCSDT shielding and CC3 spin–spin coupling

2020 ◽  
Vol 22 (37) ◽  
pp. 21350-21359
Author(s):  
Michał Jaszuński ◽  
Stephan P. A. Sauer ◽  
Rasmus Faber ◽  
David J. D. Wilson
Keyword(s):  
Ab Initio ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Coupled Cluster ◽  
Nmr Parameters ◽  
Coupled Cluster Methods ◽  
Quantitative Accuracy ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Cluster Methods

NMR shielding and spin–spin coupling constants of cis and trans isomers of FNNF have been determined to near-quantitative accuracy from ab initio calculations.

Do corresponding coupling constants in hydrogen-bonded homo- and hetero-chiral dimers differ?

2010 ◽  
Vol 88 (8) ◽  
pp. 694-699 ◽  
Author(s):  
Janet E. Del Bene ◽  
Ibon Alkorta ◽  
José Elguero
Keyword(s):  
Hydrogen Bonds ◽  
Ab Initio ◽  
Equation Of Motion ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Coupled Cluster ◽  
Absolute Value ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Isomeric Pairs

Ab initio equation-of-motion coupled cluster singles and doubles (EOM–CCSD) calculations have been carried out to evaluate spin–spin coupling constants in six pairs of homo- and hetero-chiral dimers: (HOOH)2, (H2NNH2)2, (FOOH)2, (FHNNH2)2, (HOOOH)2, and (FOOOH)2. Corresponding spin–spin coupling constants in these isomeric pairs of C2 and Ci symmetry may differ, but these differences are small and may not be detectable experimentally. For the complexes with O1–H···O and O1–H···F hydrogen bonds, 1J(O1–H) has a larger absolute value in the C2 isomer. For the same set of complexes, 1J(O1–O2) has a larger absolute value in the Ci isomer. No distinguishable patterns could be discerned in the remaining spin–spin coupling constants in the C2 and Ci isomers of these complexes, nor in complexes with N–H···N hydrogen bonds.

Structural Characterization of Natural Products By Means of Quantum Chemical Calculations of NMR Parameters: New insights

2021 ◽  
Author(s):  
Fabio Luiz Paranhos Costa ◽  
Ana Carolina Ferreira de Albuquerque ◽  
Rodolfo Goetze Fiorot ◽  
Luciano Morais Lião ◽  
Lucas Haidar Martorano ◽  
...  
Keyword(s):  
Natural Products ◽  
Structural Characterization ◽  
Quantum Chemical ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Nmr Parameters ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

The calculation of NMR parameters for natural products was pioneered by Bifulco and coworkers in 2002. Since then, modelling 1H and 13C chemical shifts and spin-spin coupling constants for this...

The Molecular Structure of Allenes and Ketenes, XIII Correlations of Carbon-Proton Spin-Spin Coupling Constants in Allenes with ab initio STO-3G Overlap Populations

1979 ◽  
Vol 34 (1) ◽  
pp. 118-120 ◽  
Author(s):  
Wolfgang Runge
Keyword(s):  
Molecular Structure ◽  
Ab Initio ◽  
Substituent Effects ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Proton Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Cl Atoms

Abstract It is shown that substituent effects on one-bond and long-range carbon-proton coupling constants in monosubstituted allenes parallel quantitatively ab initio STO-3G carbon 2s-hydrogen 1 s overlap populations, irrespectively of whether the substituents are bonded to the allenic skeleton via first-row (C, O) or second-row (Si, S, Cl) atoms.

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