Composites based on nitroprusside cyano-bridged coordination polymer particles and chitosan for NO delivery

We report the design of new composite films {Fe[Fe(CN)(5)(NO)]}(0.55)@C6H11NO4 and {Ag-2[Fe(CN)(5)(NO)]}(0.28)@C6H11NO4 based on cyano-bridged coordination polymers Fe-II[Fe-II(CN)(5)(NO)] or Ag-2(I)[Fe-II(CN)(5)(NO)] grown into a chitosan matrix that are able to provide a slow NO radical release under white light irradiation. The characterisation methods such as X-ray diffraction, TGA, SEM-EDX, IR and UV-vis spectroscopies show that these composites are made of ca. 50 wt% of the cyano-bridged coordination polymer as microcrystalline particles embedded into chitosan films. Irradiation for 7 days by using white light results in initiating a 6.5 and 10.6% NO radical delivery for {Fe[Fe(CN)(5)(NO)]}(0.55)@C6H11NO4 and {Ag-2[Fe(CN)(5)(NO)]}(0.28)@C6H11NO4, respectively. The rearrangement of the cyano-bridged coordination compounds after the NO departure leads to the formation of Prussian blue or silver Prussian blue analogues, which limits the unwanted release of cyanide as a side effect.