Synthesis of novel N-diazeniumdiolates based on hyperbranched polyethers.

Novel N-diazeniumdiolate based on hyperbranched polyethers(HP-g-DACA/N(2)O(2)) were prepared through a two-step synthesized route. The alkyltrimethoxysilane containing secondary amine groups (DACA) was used to modify the hydroxyl end groups of hyperbranched polyethers (HP) to obtain the precursor hyperbranched diamine (HP-g-DACA). Then HP-g-DACA was reacted with NO at 80psi pressure to be converted into N-diazeniumdiolates. The structures were confirmed using (13)C NMR and IR spectra. UV-vis spectroscopy measurement indicated that the aqueous solution of obtained HP-g-DACA/N(2)O(2) had a characteristic absorption at 246nm. The final HP-g-DACA/N(2)O(2) product showed NO releasing within the prolonged periods of time, and the apparent half-life t(1/2) was more than 11min in phosphate buffer at 37 degrees C. The total amount of NO released from HP-g-DACA/N(2)O(2) could achieve to 0.43micromol/mg and was proportional to the modified degree of HP by DACA. In addition, the NO loading efficiency can be modulated by the modification degree of hyperbranched macromolecular end groups.