Untitled

Design of an NO photoinduced releaser xerogel based on the controlled nitric oxide donor trans-[Ru(NO)Cl(cyclam)](PF6)2 (cyclam=1,4,8,11-tetraazacyclotetradecane)

“…However, besides the peaks at 10-70 ppm region, the 13 C MAS NMR spectrum of SiO 2 /SiNH 2 /RuNO displays a peak at 177 ppm, whose origin is not clear (see ahead). This is consistent with the UV-vis and infrared results, which give evidence of a pos- sible nucleophilic attack of the -NH 2 group on the coordinated nitrosonium [59][60][61]. This process occurs in the ammino modified xerogel but not in the SiO 2 xerogel, because of the nucleophilic character of the -NH 2 groups.…”

“…The absence of the former band and the presence of the latter indicate the absence of the NO + group. However, it has been observed that nitrosonium can undergo nucleophilic attack from an amine in solution [59][60][61]. As a matter of fact, a relatively more intense band appears at 484 nm in the spectrum of a mixture of the complex and 3-aminopropyltrietoxysilane during gel formation as a result of such reaction (see ahead).…”

“…However, the reaction product of this reaction is not clear. The reaction of some nitrosyl complexes with aromatic amines has been reported to be a diazotation reaction [59][60][61], resulting in infrared bands around 2000 cm −1 and UV-vis bands around 300 nm in the spectra of the products. In the case of trans-[Ru(NO)Cl(cyclam)](PF 6 ) 2 , there are no infrared bands at ∼2000 cm −1 in the xerogel and the band at 484 nm present in the electronic spectrum of the free complex in solution is not observed in the xerogel either, possibly because only a partial reaction occurs.…”

Coordination and Organometallic Chemistry of Metal−NO Complexes

“…Numerous octahedral ruthenium- and osmium(II) complexes of compositions [ML 5 (NO)] 3+ and [ML 4 X(NO)] 2+ [monodentate L = pyridine, − NH 3 , − phosphines, − arsines, H 2 O; bidentate L = bipyridine, ,− phenanthroline, ,, (arylazo)pyridine, , azoamines, oximates, − diamines, , diarsines, , ketoximes; tridentate L = terpyridine, , 2,6-bis(pyrazol-1-yl)pyridines; tetradentate L = 1,5,9,13-tetraazacyclohexadecane, 1,4,8,11-tetraazacyclotetradecane-5,7-dione; X = halide, OH - ] have been reported. Similar ruthenium(II) complexes containing bidentate monoanionic ligands, e.g.…”

“…798 Theoretical comparisons of the effects of NO vs NS (a stronger π-acid) coordination in these systems have also been published. 782,799 Numerous octahedral ruthenium-and osmium(II) complexes of compositions [ML 5 (NO)] 3+ and [ML 4 X-(NO)] 2+ [monodentate L ) pyridine, 800-803 NH 3 , [804][805][806][807][808][809][810][811][812][813][814][815] phosphines, [816][817][818][819][820] arsines, 816 H 2 O; 812 bidentate L ) bipyridine, 800,821-831 phenanthroline, 829,830,832 (arylazo)pyridine, 833,834 azoamines, 835 oximates, [836][837][838][839][840][841] diamines, 772,842 diarsines, 829,843 ketoximes; 844 tridentate L ) terpyridine, 818,835 2,6-bis(pyrazol-1-yl)pyridines; 819 tetradentate L ) 1,5,9,13-tetraazacyclohexadecane, 845 1,4,8,11-tetraazacyclotetradecane-5,7-dione; 846 X ) halide, OH -] have been reported. Similar ruthenium(II) complexes containing bidentate monoanionic ligands, e.g.…”