ChemInform Abstract: Software Approaches for Determination of 3-Dimensional Molecular Structures from Multi-Dimensional NMR

ChemInform ◽  
2010 ◽  
Vol 23 (52) ◽  
pp. no-no
Author(s):  
G. C. LEVY ◽  
S. WANG ◽  
P. KUMAR ◽  
G. W. JEONG ◽  
P. N. BORER
Keyword(s):  
Molecular Structures ◽  
3 Dimensional

Crystal structure determination of the conformation of two bicyclo[3.3.1]nonan-ones

1985 ◽  
Vol 63 (6) ◽  
pp. 1166-1169 ◽  
Author(s):  
John F. Richardson ◽  
Ted S. Sorensen
Keyword(s):  
Crystal Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Molecular Structures ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Final Agreement

The molecular structures of exo-7-methylbicyclo[3.3.1]nonan-3-one, 3, and the endo-7-methyl isomer, 4, have been determined using X-ray-diffraction techniques. Compound 3 crystallizes in the space group [Formula: see text] with a = 15.115(1), c = 7.677(2) Å, and Z = 8 while 4 crystallizes in the space group P21 with a = 6.446(1), b = 7.831(1), c = 8.414(2) Å, β = 94.42(2)°, and Z = 2. The structures were solved by direct methods and refined to final agreement factors of R = 0.041 and R = 0.034 for 3 and 4 respectively. Compound 3 exists in a chair–chair conformation and there is no significant flattening of the chair rings. However, in 4, the non-ketone ring is forced into a boat conformation. These results are significant in interpreting what conformations may be present in the related sp2-hybridized carbocations.

Hapticity of asymmetric rhodium-allyl compounds in the light of real-space bonding indicators

2018 ◽  
Vol 233 (9-10) ◽  
pp. 615-626
Author(s):  
Stefan Mebs ◽  
Sabrina Imke Kalläne ◽  
Thomas Braun
Keyword(s):  
Real Space ◽  
Molecular Structures ◽  
Dft Study ◽  
Interaction Patterns ◽  
Ligand Interaction ◽  
Complex Metal ◽  
Allyl Compounds ◽  
Back Donation ◽  
Metal Ligand

Abstract Rhodium boryl complexes are valuable catalysts for hydro- or diboration reactions of alkenes, but can also react with ketones (R2C=O) and imines (R2C=NR′) giving rise to insertion products having formally Rh–R2C–O/NR′–B linkages. The resulting molecular structures, however, may show complex metal–ligand and ligand–ligand interaction patterns with often unclear metal–ligand connectivities (hapticities, ηn). In order to assign the correct hapticity in a set of asymmetric rhodium-allyl compounds with molecular structures indicating η1−5 bonding, a comprehensive DFT study was conducted. The study comprises determination of a variety of real-space bonding indicators derived from computed electron and pair densities according to the AIM, ELI-D, NCI, and DORI topological and surface approaches, which uncover the metal–ligand connectivties and suggest an asymmetric ligand–metal donation/metal–ligand back-donation framework according to the Dewar–Chatt–Duncanson model.

Ultrafast Electron Diffraction (UED). A New Development for the 4D Determination of Transient Molecular Structures

ChemInform ◽  
2003 ◽  
Vol 34 (40) ◽  
Author(s):  
Ramesh Srinivasan ◽  
Vladimir A. Lobastov ◽  
Chong-Yu Ruan ◽  
Ahmed H. Zewail
Keyword(s):  
Electron Diffraction ◽  
Molecular Structures ◽  
Ultrafast Electron Diffraction ◽  
New Development
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