Aromatic dipeptides and their salts—Solid-state linear-dichroic infrared (IR-LD) spectral analysis and ab initio calculations

2008 ◽  
Vol 70 (2) ◽  
pp. 324-331 ◽  
Author(s):  
Bojidarka B. Ivanova
Keyword(s):  
Spectral Analysis ◽  
Solid State ◽  
Ab Initio Calculations ◽  
Ab Initio

On the tautomerism of 1-phenyl-3-substituted-pyrazol-5-ones and their photoinduced products — experimental and theoretical UV spectral analysis

2008 ◽  
Vol 62 (3) ◽  
Author(s):  
Atanas Chapkanov ◽  
Bojidarka Koleva ◽  
Michail Arnaudov ◽  
Ivan Petkov
Keyword(s):  
Spectral Analysis ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Uv Spectra ◽  
Basis Set ◽  
Geometrical Parameters ◽  
Tautomeric Forms

AbstractA detailed experimental and theoretical UV-spectral analysis of the tautomeric forms of 3-methyl-1-phenyl pyrazol-5-one and 1,3-diphenyl pyrazol-5-one as well as of the UV-irradiated photoinduced products of the latter compound were carried out. The experimental UV-spectra were compared with the theoretical ones obtained by CIS/6-31G**. Selected geometrical parameters of the different tautomers were estimated by ab initio calculations using the RHF/6-31G** level of theory and basis set, which have also been discussed with a view to the corresponding UV-results.

scholarly journals Coupling Solid-State NMR with GIPAW ab Initio Calculations in Metal Hydrides and Borohydrides

2013 ◽  
Vol 117 (19) ◽  
pp. 9991-9998 ◽  
Author(s):  
Federico Franco ◽  
Marcello Baricco ◽  
Michele R. Chierotti ◽  
Roberto Gobetto ◽  
Carlo Nervi
Keyword(s):  
Solid State ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Solid State Nmr ◽  
Metal Hydrides

31P chemical shielding as a function of bond angle: phosphorus chemical shielding surface of phosphinoborane R2PBR'2

1999 ◽  
Vol 77 (11) ◽  
pp. 1951-1961 ◽  
Author(s):  
Michael JT Ditty ◽  
William P Power
Keyword(s):  
Solid State ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Principal Components ◽  
Bond Angle ◽  
Good Description ◽  
Chemical Shielding ◽  
Orbital Theory ◽  
Shielding Tensor ◽  
Theory Calculation

The phosphorus chemical shielding surface of phosphinoborane R2PBR'2 has been investigated via molecular orbital theory calculation and experimental measurement of selected derivatives. Ab initio calculations of phosphorus chemical shielding tensors were determined for the phosphinoboranes H2PBH2 and (CH3)2PB(CH3)2. Changes in the angle from planarity, i.e., that between the P-BR'2 plane and the bisector of the RPR angle, are reflected in the orientations and magnitudes of the three principal components of the phosphorus chemical shielding tensor. To determine the validity of the calculated phosphorus chemical shielding surface, three phosphinoborane compounds with different angles from planarity were synthesized and studied by solid-state 31P NMR spectroscopy. The 31P NMR powder patterns provided experimental magnitudes of the principal components of the phosphorus chemical shielding tensor for each compound, which compared well to the calculated predictions; where orientations of these tensors could be determined experimentally, they also agreed well with the calculated results. The combined experimental and theoretical results provide a good description of the effects on changes in bond angle on phosphorus chemical shielding as the molecule is distorted from a planar to folded geometry.Key words: chemical shielding, solid-state NMR, phoshinoborane, ab initio calculations.

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