A floating spherical Gaussian orbital model of molecular structure. ESCA chemical shifts for inner shell electrons for small hydrocarbons

1972 ◽  
Vol 13 (6) ◽  
pp. 610-612 ◽  
Author(s):  
J.L. Nelson ◽  
A.A. Frost
Keyword(s):  
Molecular Structure ◽  
Chemical Shifts ◽  
Gaussian Orbital

Synthesis, Conformational Analysis and Crystal Structure of New Thioxo, Oxo, Seleno Diastereomeric Cyclophosphamides Containing 1,3,2-dioxaphosphorinane

2019 ◽  
Vol 23 (2) ◽  
pp. 205-213
Author(s):  
Dorra Kanzari-Mnallah ◽  
Med L. Efrit ◽  
Jiří Pavlíček ◽  
Frédéric Vellieux ◽  
Habib Boughzala ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Density Functional ◽  
Chemical Shifts ◽  
Structural Determination ◽  
Conformational Study ◽  
Functional Theory ◽  
One Step ◽  
High Resolution Mass Spectroscopy ◽  
Resolution Mass

Thioxo, Oxo and Seleno diastereomeric cyclophosphamides containing 1,3,2- dioxaphosphorinane are prepared by a one-step chemical reaction. Their structural determination is carried out by means of Nuclear Magnetic Resonance NMR (31P, 1 H, 13C) and High-Resolution Mass Spectroscopy (HRMS). The conformational study of diastereomeric products is described. Density Functional Theory (DFT) calculations allowed the identification of preferred conformations. Experimental and calculated 31P, 13C, 1H NMR chemical shifts are compared. The molecular structure of the 2-Benzylamino-5-methyl-5- propyl-2-oxo-1,3,2-dioxaphosphorinane (3d) has been determined by means of crystal Xray diffraction methods.

Structure of 4,4-Bisphenylsulfonyl-N,N-dimethylbutylamine: Interplay of Intramolecular C–H···N, C–H···O=S, and ?···? Interactions

2009 ◽  
Vol 62 (9) ◽  
pp. 1062 ◽  
Author(s):  
Jiong Ran ◽  
Ming Wah Wong
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bond ◽  
Significant Interaction ◽  
Chemical Shifts ◽  
Intramolecular Interactions ◽  
Methyl Derivative ◽  
Polar Medium ◽  
Conformational Properties ◽  
Density Analysis ◽  
Experimental Findings

Conformations of 4,4-bisphenylsulfonyl-N,N-dimethylbutylamine (BSDBA) were examined by ab initio calculations. Intramolecular C–H···N, C–H···O, and π···π interactions are found to play an important role in governing the conformational properties. This finding is supported by charge density analysis based on the theory of atoms in molecules. The calculated molecular structure and 1H chemical shifts of the methyl derivative (BSTBA) are in excellent agreement with experimental findings. The intramolecular C–H···N hydrogen bond in BSDBA is estimated to have a significant interaction energy of 25 kJ mol–1. The sulfonyl oxygens in BSDBA interact readily with neighbouring methylene, methyl and phenyl hydrogens via C–H···O=S hydrogen bonds. In agreement with experiment, solvent effect calculations indicate that these weaker intramolecular interactions prevail in an aprotic polar medium.

The Molecular Structure of Allenes and Ketenes, XI Semiempirical Calculations of 1H-Chemical Shifts of Allenes

1977 ◽  
Vol 32 (11) ◽  
pp. 1296-1303 ◽  
Author(s):  
W. Runge
Keyword(s):  
Molecular Structure ◽  
Boundary Conditions ◽  
Chemical Shifts ◽  
Quantitative Description ◽  
Algebraic Model ◽  
Coupling Constants ◽  
Semiempirical Calculations ◽  
Proton Coupling ◽  
Nmr Data ◽  
Proton Chemical Shifts

A comparison between calculated and observed values demonstrates that “ansätze” derived from an algebraic model in connection with appropriate boundary conditions are able to account for a quantitative description of the proton chemical shifts of allenes.Correlations of the proton chemical shifts with other NMR data, such as 13C-chemical shifts and one-bond carbon-proton coupling constants, reveal some insigths into the nature of the 1H substituent chemical shifts of alienes.

scholarly journals A multinuclear NMR study of some cyclic phosphonic diamides

1994 ◽  
Vol 12 (1) ◽  
pp. 31-34
Author(s):  
Wojciech Bocian ◽  
Lech Stefaniak ◽  
Graham A. Webb
Keyword(s):  
Molecular Structure ◽  
Chemical Shifts ◽  
Multinuclear Nmr ◽  
Nmr Data ◽  
Nmr Study ◽  
Sensitive Parameters

1H,13C,15N and31p NMR data are presented for four cyclic phosphonic diamides. In tenns of useful structural infonnation it is found that the31p chemical shifts and1J(31P_15N) couplings are the most sensitive parameters to variations in molecular structure.

9-Borafluorenes – NMR spectroscopy and DFT calculations. Molecular structure of 1,2-(2,2′-diphenylylene)-1,2-diethyldiborane

2010 ◽  
Vol 75 (7) ◽  
pp. 743-756 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Peter Thoma ◽  
Rhett Kempe ◽  
Germund Glatz
Keyword(s):  
Molecular Structure ◽  
Nmr Spectroscopy ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spin Coupling ◽  
X Ray Diffraction ◽  
Data Set ◽  
Chemical Shift Tensors ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

9-Borafluorene derivatives 1 (9-R = Et (a), Ph (b), Cl (c), NEt2 (d)), the pyridine adduct 1py+ and 1,2-(2,2′-biphenylylene)-1,2-diethyldiborane(6) (3), were studied by 11B and 13C NMR spectroscopy to obtain a fairly complete data set for the first time. The molecular structure of the doubly hydrogen-bridged 1,2-diphenylenediborane 3 was determined by X-ray diffraction. The gas-phase structures of the compounds 1, related derivatives, and of some doubly hydrogen-bridged 1,2-diphenylenediboranes were optimized by quantum chemical calculations (B3LYP/6-311+G(d,p) level of theory) and NMR parameters, such as chemical shifts, 11B chemical shift tensors and indirect nuclear 13C–11B spin–spin coupling constants were calculated at the same level of theory and compared with experimental data.

Synthesis of Rhodium Complexes with Novel Perfluoroalkyl Substituted Cyclopentadienyl Ligands

2001 ◽  
Vol 66 (2) ◽  
pp. 382-396 ◽  
Author(s):  
Jan Čermák ◽  
Kateřina Auerová ◽  
Huong Thi Thu Nguyen ◽  
Vratislav Blechta ◽  
Pavel Vojtíšek ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Chemical Shifts ◽  
Rhodium Complexes ◽  
Carbonyl Complexes ◽  
X Ray Diffraction ◽  
Metal Catalysis ◽  
Chloro Complexes ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
C Nmr

Mixtures of isomers of (perfluoroalkyl)tetramethylcyclopenta-1,3-dienes (CH3)4C5H(CF2)nCF3 (n = 3, 5, 7, 9) were synthesized as precursors of new cyclopentadienyl ligands for organotransition metal catalysis in fluorous biphase media and characterized by combination of GC-MS and 13C NMR spectroscopy. Rhodium(III) chloro complexes [Rh{(CH3)4C5(CF2)nCF3}Cl2]2 and rhodium(I) carbonyl complexes [Rh{(CH3)4C5(CF2)nCF3}(CO)2] were prepared from the cyclopentadienes and molecular structure of [Rh{(CH3)4C5(CF2)5CF3}Cl2]2 was determined by X-ray diffraction. The ligands are electronically close to the unsubstituted cyclopentadienyl as shown by values of carbonyl stretching frequencies in the carbonyl complexes. Neither carbonyl frequencies nor NMR chemical shifts of the complexes are substantially affected by the length of the perfluoroalkyl chain.

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