TY  - JOUR
A1  - Szatmari, Istvan
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Fulop, Ferenc
A1  - Kleinpeter, Erich
T1  - Unexpected isomerization of new naphth[1,3]oxazino[2,3-a] isoquinolines in solution, studied by dynamic NMR and supported by theoretical DFT computations
JF  - Tetrahedron
N2  - Through the reactions of 1-aminomethyl-2-naphthol and substituted 1-aminobenzyl-2-naphthols with 3,4-dihydroisoquinoline or 6,7-dimethoxy-3,4-dihydroisoquinoline under microwave conditions, naphth[1,2-e][1,3]oxazino[2,3-a]-isoquinoline derivatives were prepared in good yields. The latter reaction was extended by using 2-aminoarylmethyl-1-naphthols, leading to isomeric naphth-[2,1-e][1,3]oxazino[2,3-a] isoquinolines. Beside the detailed NMR spectroscopic and theoretical study of both stereochemistry and dynamic behaviour of these new conformational flexible heterocyclic ring systems an unexpected dynamic process between two diastereomers was observed in solution, studied by variable temperature H-1 NMR spectroscopy and the mechanism proved by theoretical DFT computations.
KW  - 3,4-Dihydroisoquinoline
KW  - Aminonaphthol
KW  - Dynamic NMR spectroscopy
KW  - DFT calculations
KW  - Conformational analysis
Y1  - 2013
U6  - https://doi.org/10.1016/j.tet.2013.06.094
SN  - 0040-4020
VL  - 69
IS  - 35
SP  - 7455
EP  - 7465
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Demetriou, Antri
A1  - Pashalidis, Ioannis
A1  - Nicolaides, Athanassios V.
A1  - Kumke, Michael Uwe
T1  - Surface mechanism of the boron adsorption on alumina in aqueous solutions
JF  - Desalination and water treatment : science and engineering
N2  - The adsorption of boron (boric acid) from aqueous solutions on alumina has been investigated at pH 8.0, I=0.1M NaClO4, T=22 +/- 3 degrees C, and under normal atmospheric conditions. The characterization of the adsorbed species was performed by Raman spectroscopy and the spectroscopic speciation was assisted by theoretical DFT calculations. Evaluation of the spectroscopic data points to the formation of inner-sphere surface complexes and indicates the formation of two different types of adsorbed boron species. The theoretical calculations corroborate the spectroscopic data and indicate that at low boron concentration the monodentate surface species dominates, whereas increased boron concentration favors the formation of a bidentate surface species. Assuming low coverage, the conditional formation constant for the monodentate surface species has been evaluated to be log=4.1 +/- 0.1.
KW  - Boric acid
KW  - Alumina
KW  - Raman spectroscopy
KW  - DFT calculations
KW  - Surface complexes
KW  - Formation constant
Y1  - 2013
U6  - https://doi.org/10.1080/19443994.2013.764354
SN  - 1944-3994
SN  - 1944-3986
VL  - 51
IS  - 31-33
SP  - 6130
EP  - 6136
PB  - Taylor & Francis Group
CY  - Philadelphia
ER  -