Quantum Chemical Calculations on Structural Models of the Catalytic Site of Chymotrypsin:  Comparison of Calculated Results with Experimental Data from NMR Spectroscopy

2002 ◽  
Vol 124 (48) ◽  
pp. 14373-14381 ◽  
Author(s):  
William M. Westler ◽  
Frank Weinhold ◽  
John L. Markley
Keyword(s):  
Experimental Data ◽  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structural Models ◽  
Catalytic Site

Electronic Structure and Optical Response of Electroluminescent Conjugated Polymers

1997 ◽  
Vol 488 ◽  
Author(s):  
J. L. Bredas ◽  
J. Cornil ◽  
D. Beljonne ◽  
D. A. Dos Santos ◽  
Z. Shuaiv ◽  
...  
Keyword(s):  
Experimental Data ◽  
Optical Properties ◽  
Electronic Structure ◽  
Quantum Yield ◽  
Conjugated Polymers ◽  
Quantum Chemical Calculations ◽  
Theoretical Approach ◽  
Quantum Chemical ◽  
Fluorescence Quantum Yield ◽  
Remarkable Agreement

AbstractIn this contribution, we investigate by means of correlated quantum-chemical calculations the influence of intermolecular interactions on the absorption and emission properties of conjugated chains. Various strategies are suggested to avoid a substantial decrease in fluorescence quantum yield in condensed media. Finally, the reliability of our theoretical approach is validated by showing the remarkable agreement obtained between the experimental data and the calculated optical properties of clusters formed by sexithienyl molecules.

Hydrogen-Bonding and the Dissolution Mechanism of Uracil in an Acetate Ionic Liquid: New Insights from NMR Spectroscopy and Quantum Chemical Calculations

2013 ◽  
Vol 117 (15) ◽  
pp. 4109-4120 ◽  
Author(s):  
João M. M. Araújo ◽  
Ana B. Pereiro ◽  
José N. Canongia Lopes ◽  
Luís P. N. Rebelo ◽  
Isabel M. Marrucho
Keyword(s):  
Ionic Liquid ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Dissolution Mechanism

scholarly journals Argentate(i) and (iii) complexes as intermediates in silver-mediated cross-coupling reactions

2018 ◽  
Vol 54 (40) ◽  
pp. 5086-5089 ◽  
Author(s):  
Sebastian Weske ◽  
Richard A. Hardin ◽  
Thomas Auth ◽  
Richard A. J. O’Hair ◽  
Konrad Koszinowski ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Esi Mass Spectrometry

Silver-mediated cross-coupling reactions proceed via anionic ate complexes, which have been characterized by a combination of NMR spectroscopy, ESI mass spectrometry, and quantum-chemical calculations.

scholarly journals Z and E rotamers of N -formyl-1-bromo-4-hydroxy-3-methoxymorphinan-6-one and their interconversion as studied by 1 H/13 C NMR spectroscopy and quantum chemical calculations

2012 ◽  
Vol 51 (2) ◽  
pp. 82-88 ◽  
Author(s):  
Agnieszka Sulima ◽  
Kejun Cheng ◽  
Arthur E. Jacobson ◽  
Kenner C. Rice ◽  
Klaus Gawrisch ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
C Nmr

Determining the Geometry of Hydrogen Bonds in Solids with Picometer Accuracy by Quantum-Chemical Calculations and NMR Spectroscopy

ChemPhysChem ◽  
2005 ◽  
Vol 6 (2) ◽  
pp. 315-327 ◽  
Author(s):  
Martin Schulz-Dobrick ◽  
Thorsten Metzroth ◽  
Hans Wolfgang Spiess ◽  
J�rgen Gauss ◽  
Ingo Schnell
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical

Problems with a conformation assignment of aryl-substituted resorc[4]arenes

2011 ◽  
Vol 76 (10) ◽  
pp. 1199-1222 ◽  
Author(s):  
Jakub Kaminský ◽  
Hana Dvořáková ◽  
Jan Štursa ◽  
Jitka Moravcová
Keyword(s):  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Quantum Chemical Calculations ◽  
Dynamic Process ◽  
Quantum Chemical ◽  
Energy Barrier ◽  
Π Interactions ◽  
Temperature Range ◽  
Acid Catalyzed

Acid-catalyzed condensation of resorcinol with 3,5-diisopropoxybenzaldehyde and 3,5-dihydroxybenzaldehyde afforded aryl substituted resorc[4]arenes 1a and 1b, respectively. All 16 hydroxyls in 1b were acetylated providing resorc[4]arene 1c. The conformational behaviour of 1a, 1b and 1c was studied by NMR spectroscopy and quantum chemical calculations. It was found that the stabilization of their conformations is an effect of competing π-π and OH-π interactions, hydrogen bonding and steric features, respectively. As a result, C2 symmetrical boat conformations 1a, 1b and 1c with aryls in axial positions were identified in all cases. In case of 1c also the formation of C2 symmetrical conformation with aryls in equatorial positions (boat-eq) was identified. Moreover, compounds 1a and 1b being able to create hydrogen bonds, adopt also symmetrical C4 crown conformations. For 1c(boat-ax), the boat-boat conversion with energy barrier of 80 kJ/mol was observed, while the 1c(boat-eq) was found to be rigid in the whole accessible temperature range. Both conformers of 1c exhibit also second dynamic process – rotation of bridge aryl rings (ΔG‡ = 66 kJ/mol).

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