0000000001315001
AUTHOR
Marek Pietrzak
Association of N-(Pyridin-2-yl),N′-substituted Ureas with 2-Amino-1,8-naphthyridines and Benzoates: NMR and Quantum Chemical Studies of the Substituent Effect on Complexation
Association of four N-(pyridin-2-yl),N'-R(1)-ureas (R(1) = ethyl, n-butyl, phenyl, and tert-butyl) with substituted 2-amino-1,8-naphthyridines and benzoates were studied by (1)H NMR spectroscopic titrations and quantum chemical calculations. The benzoates and 2-amino-1,8-naphthyridines were selected as representatives of double and triple hydrogen bonding counterparts, respectively. The classical substituent effect on the association was studied. A prerequisite and a crucial step for the complex formation was the breaking of the intramolecular hydrogen bond in urea derivatives. The QTAIM calculation method was employed to explain the hydrogen bonding within complexes. In the case of benzoat…
Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case
The association of substituted benzoates and naphthyridine dianions was used to study the complexation of dibutyltriuret. The title molecule is the simplest molecule able to form two intramolecular hydrogen bonds. The naphthyridine salt was used to break two intramolecular hydrogen bonds at a time while with the use of substituted benzoates the systematic approach to study association was achieved. Both, titrations and variable temperature measurements shed the light on the importance of conformational equilibrium and its influence on association in solution. Moreover, the associates were observed by mass spectrometry. The DFT-based computations for complexes and single bond rotational barr…
Substituent effects on the photophysical properties of fluorescent 2-benzoylmethylenequinoline difluoroboranes: A combined experimental and quantum chemical study
Abstract In this study, we demonstrate a successful synergy between theory and experiment and report on the photophysical properties of a recently synthesized series of substituted 2-benzoylmethylenequinoline difluoroboranes with a view towards the effect of substitution on their properties. In general difluoroboranes are known to have a bright fluorescence but for some analogs the properties are not fully understood. Quantum chemistry methods have been applied in order to explain a complex structure of the absorption and emission spectra and to gain an insight into the charge redistribution upon the excitation of the investigated molecules. We demonstrate that the spectra of this important…
CCDC 1422861: Experimental Crystal Structure Determination
Related Article: Borys Ośmiałowski, Karina Mroczyńska, Erkki Kolehmainen, Magdalena Kowalska, Arto Valkonen, Marek Pietrzak, and Kari Rissanen|2013|J.Org.Chem.|78|7582|doi:10.1021/jo4011393
CCDC 1422862: Experimental Crystal Structure Determination
Related Article: Borys Ośmiałowski, Karina Mroczyńska, Erkki Kolehmainen, Magdalena Kowalska, Arto Valkonen, Marek Pietrzak, and Kari Rissanen|2013|J.Org.Chem.|78|7582|doi:10.1021/jo4011393
CCDC 1422860: Experimental Crystal Structure Determination
Related Article: Borys Ośmiałowski, Karina Mroczyńska, Erkki Kolehmainen, Magdalena Kowalska, Arto Valkonen, Marek Pietrzak, and Kari Rissanen|2013|J.Org.Chem.|78|7582|doi:10.1021/jo4011393