Dihydrogen-bonded complexes of xenon dihydride with water: Ab initio calculations and topological analysis of electron localisation function (ELF)

2000 ◽  
Vol 2 (24) ◽  
pp. 5521-5527 ◽  
Author(s):  
Jan Lundell ◽  
Slawomir Berski ◽  
Zdzislaw Latajka
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Topological Analysis ◽  
Bonded Complexes

Analysis of magnesium–carbon bonding in magnesium anthracene systems

1996 ◽  
Vol 74 (6) ◽  
pp. 801-809 ◽  
Author(s):  
Ralf Stegmann ◽  
Gernot Frenking
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electron Density ◽  
Chemical Shifts ◽  
Topological Analysis ◽  
Nbo Analysis ◽  
Experimental Values ◽  
A Charge ◽  
Good Agreement ◽  
Carbon Bonding

Ab initio calculations at the MP2/3-21G(*) level of theory have been carried out for the magnesium–anthracene complexes 9,10-magnesiumanthracene•3H2O (1) and the 9-methyl (2), dimethyl (3), and 9,10-bis(methylsilyl) (4) substituted derivatives. The theoretically predicted geometries of the anthracene ligands are also reported. The calculated geometries of 1–4 are in very good agreement with experimental values for the corresponding THF complexes. The Mg—C9,10 bonds of the bridged structures are rather long and the anthracene ligands are folded by ~40° along the C9–C10 line in the complexes. Analysis of the electronic structure shows clearly that the Mg—C9,10 bonds should be considered as purely ionic. This is revealed by topological analysis of the electron density distribution and its associated Laplacian. The electron density at the Mg—C9,10 bond critical points ρ(rb) is very low and the Laplacian [Formula: see text] and the energy density Hb have positive values. The ionic nature of the Mg—C9,10 bond is also indicated by the natural bond order (NBO) analysis, which gives a Lewis structure with two lone pairs at C9 and C10 but no Mg—C9,10 bonds. The NBO method gives a charge donation from Mg to the anthracene ligand of nearly two. The theoretically predicted NMR chemical shifts using the GIAO method give 13C resonances for the complex 1 and for anthracene and anthracene dianion that are in good agreement with experimental values. Key words: magnesium–anthracene complexes, ab initio calculations, analysis of magnesium–carbon bonding.

Millimetre-wave and infrared spectroscopy of Br13 CN: anharmonic force field of cyanogen bromide from spectroscopic data and ab initio calculations

1997 ◽  
Vol 90 (3) ◽  
pp. 495-497
Author(s):  
CLAUDIO ESPOSTI ◽  
FILIPPO TAMASSIA ◽  
CRISTINA PUZZARINI ◽  
RICCARDO TARRONI ◽  
ZDENEK ZELINGER
Keyword(s):  
Infrared Spectroscopy ◽  
Force Field ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Spectroscopic Data ◽  
Cyanogen Bromide ◽  
Millimetre Wave ◽  
Anharmonic Force
Sign in / Sign up

Export Citation Format

Share Document