1236183-21-3Relevant articles and documents
Hybridization of long pyridine-dicarboxamide oligomers into multi-turn double helices: Slow strand association and dissociation, solvent dependence, and solid state structures
Baptiste, Benoit,Zhu, Jiang,Haldar, Debasish,Kauffmann, Brice,Leger, Jean-Michel,Huc, Ivan
, p. 1364 - 1375 (2011/08/10)
Oligoamides of 2,6-diamino- pyridine and 2,6-pyridinediearboxylie aeid eomprised of 5, 7, 9, 11, or 13 units and bearing 4-isobutoxyehains on all pyridine rings and tert-butyl-earba- mate terminal groups have been synthesized stepwise, along with an 11 mer having benzyl-earbamate terminal groups. The erystal strueture of all five Boe-terminated eompounds has been obtained and shows a highly regular and eonserved double helieal hybridization motif of up to 3 eomplete turns for the 13 mer. Four pyridine units span one helieal turn and define a helix piteh of ca 7 A. Solution studies in CDCl3 demonstrated that the Boe-terminated oligomers strongly hybridize in this solvent, and that Kdim values incerease with oligomer length. The Kdim values are 31000 and 7x 105 Lmol-1 for the 7 mer and the 9 mer, respeetively, and are too high to be measured by NMR for the 11 mer and the 13 mer. Hybridization and dissoeiation kineties at 2 mM proeeed at deereasing rates upon inereasing oligomer length. The rate was faster than minutes for the 7 mer, of the order of hours for the 9 mer, and days for the 11 mer and 13 mer. The same trend was observed in [D5]pyridine but with eonsiderably lower Kdim values and faster kineties. The benzylearbamate 11 mer was also found to hybridize into a double helix but with redueed Kdim values and faster kineties eompared to its Boe-terminated analogue. Combined with previous studies, the results presented here frame a global understanding of the hybridization of these pyridineearboxamide oligomers and provide useful guidelines for the design of other artifi- eial double heliees.
