Inversion of Population Distribution of Felodipine Conformations at Increased Concentration in Dimethyl Sulfoxide Is a Prerequisite to Crystal Nucleation

Diastereomeric preference of a triply axial chiral binaphthyl based molecule: a concentration dependent study by chiroptical spectroscopies

“…Although such observations appear not to have been extensively studied, there are a number of theoretical and experimental publications when similar concentration dependent conformational preferences were reported. [32][33][34] For example, inversion of population distribution of felodipine conformations at increasing concentration in DMSO was observed by Khodov and co-workers in 2014. 33 Using NMR spectroscopy, these authors concluded that conformational preference of felodipine in DMSO is concentration dependent: conformers that dominate in a dilute solution become the least abundant in the saturated one.…”

“…[32][33][34] For example, inversion of population distribution of felodipine conformations at increasing concentration in DMSO was observed by Khodov and co-workers in 2014. 33 Using NMR spectroscopy, these authors concluded that conformational preference of felodipine in DMSO is concentration dependent: conformers that dominate in a dilute solution become the least abundant in the saturated one. Furthermore, they pointed out that conformers that dominate in the saturated solution are of the same type as revealed in the crystalline state by X-ray.…”

High-pressure NMR spectroscopy in studies of the conformational composition of small molecules in supercritical carbon dioxide

“…Therefore, developing approaches to control the conformational ensembles of molecules in a supercritical solvent is very important. A significant progress in studies of conformational state of molecules of biologically active compounds has been achieved recently using NMR spectroscopy [7][8][9][10][11][12][13][14][15][16] and vibrational spectroscopy [17][18][19][20][21][22][23].. A correlation between the distribution of the conformers of ibuprofen in supercritical carbon dioxide and fraction of the polymorphs arising in supercritical sedimentation has been found with the aid of vibrational spectroscopy and MD simulations [20]. This example shows clearly that vibrational spectroscopy can give information on the conformational manifolds of small molecules which would be in a good agreement with MD simulations.…”

“…showed that in the case of fast conformational exchange, the cross-relaxation rate observed in a NOESY experiment is an average of the rates corresponding to individual conformers[81]: us to express the fractions xi of the forms in the case of two-position exchange based on the known distances[12]:…”

Accuracy of Determination of Self-Diffusion Coefficients in Studies of Porphyrin-Based Complexes by 2D DOSY

“…NMR spectroscopy is widely used in investigations of structure and dynamics of small molecular weight compounds [1][2][3][4][5] as well as of relatively large macrocyclic molecules, [6][7][8][9][10][11] including porphyrins. [12][13][14][15] Modern NMR methods play a special role in studied of formation of intermolecular complexes and associates, [16][17][18] and in identifying supramolecular assemblies.…”