Synthesis of novel N-diazeniumdiolates based on hyperbranched polyethers

Novel N-diazeniumdiolate based on hyperbranched polyethers(HP-g-DACA/N2O2) 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 13C NMR and IR spectra. UV–vis spectroscopy measurement indicated that the aqueous solution of obtained HP-g-DACA/N2O2 had a characteristic absorption at 246 nm. The final HP-g-DACA/N2O2 product showed NO releasing within the prolonged periods of time, and the apparent half-life t1/2 was more than 11 min in phosphate buffer at 37 °C. The total amount of NO released from HP-g-DACA/N2O2 could achieve to 0.43 μmol/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.