کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5219754 | 1383366 | 2012 | 10 صفحه PDF | دانلود رایگان |
We investigated the threading of bis(benzimidazolium) methane moieties with DB24C8 at 35 °C (room temperature) and found a high degree of association. The presence of threaded complexes was determined by 1H NMR and also supported by high resolution mass spectrometry and B3LYP/6-31G**++calculations. A 2D NMR study was done to elucidate the host-guest geometry and the molecular interactions present. The variable temperature NMR experiment was done over a temperature range of 243-323 K. The threading was stable and visible even at 323 K. Acid-base equilibrium established the reversibility of the process. DFT optimized structures establish that two H-bonded links are present between O1â¯O4â² and O3â¯O2â² across the dibenzo axis of the crown.
We investigated the threading of bis (benzimidazolium)methane moieties with DB24C8 at 35 °C (room temperature) and found a high degree of association. Variable temperature NMR experiments (243-323 K) proved the stability of the complex at 323 K. The DFT optimized structures show two H-bonded links are present between O1â¯O4â² and O3â¯O2â².
Journal: Tetrahedron - Volume 68, Issue 47, 25 November 2012, Pages 9826-9835