Reaction of some cobalt nitrosyl complexes with oxygen

Reactivity of iron(II)-bound nitrosyl hydride (HNO, nitroxyl) in aqueous solution

“…Well characterized complexes with HNO and NO -as ligands have been prepared in the last decade, noticeably with d 6 low-spin metals such as Ru II [25][26][27][28], Os II [27,[29][30][31], Re I [31][32][33], Ir III [29] (for HNO), and with Co III [34][35][36][37][38], Cr III [39][40][41], Pt IV [42], Ru II [27], and Fe II [43][44][45][46][47] (for NO -), generally by using chelating macrocyclic coligands (viz., with porphyrins, aza-macrocycles, and thioether binding species) [24]. In general, a main drawback relates to the low solubility in water and the very limited presence of iron complexes.…”

Mechanistic Studies on the Reaction of Nitroxylcobalamin with Dioxygen: Evidence for Formation of a Peroxynitritocob(III)alamin Intermediate

“…While peroxynitrite (ONOO − ) is relatively stable in solution, 50 Given that pK a (ONOOH) is 6.8 57 and that the pK a of a ligand lowers upon coordination of the ligand to a metal center, 58 Others have also observed that the presence of strong base coordinated trans to the nitrosyl group of cobalt nitrosyl complexes leads to an accelerated rate of reaction with O 2 , 23,30,59 and the same is also true for other metal-NO complexes. 60 Reaction intermediates were not observed for the NOCbl + O 2 reaction even with 0.5 equiv of O 2 , consistent with rate-determining electrophilic attack of O 2 on NOCbl, with subsequent rapid reactions to generate the H 2 OCbl + / HOCbl and NO 2 Cbl products.…”

“…A bimolecular mechanism for formation of the corresponding nitro-Co(III) complex from the peroxynitritocobalt(III) intermediate has been proposed by others, with Co(III)-bound peroxynitrite reacting with Co(III)-NO − to give NO 2 Cbl, Scheme 3. 30,31 If the reaction proceeds via this type of reaction pathway, the NO 2 Cbl:(H 2 OCbl + + HOCbl) product ratio will be dependent on the total cobalamin concentration, 31 with more NO 2 Cbl expected at higher cobalamin concentrations. However, HPLC experiments showed that the NO 2 Cbl:H 2 OCbl + product ratio is the same 61 Additionally Richter-Addo et al 60 found that the rate of the reaction of the picket fence porphyrin complex [Fe(tpivpp)(NO)] with air in CHCl 3 solution is enhanced by light.…”

Kinetics and vaporization of anil in nitrogen atmosphere – Non-isothermal condition

“…Schiff bases have found wide applications in the field of coordination chemistry (Sallam, 2006), biological processes (Snatos et al, 2005), several enzymes (Clarkson and Basolo, 1973), microcalorimetry (Li-Xia et al, 2006), cytotoxic (Tarafder et al, 2002), insulin mimetic agents (McNeill et al, 1992), anticonvulsant (Panchagnula et al, 2004), antiproliterative (Vicini et al, 2003), antifungal activities (Pignatello et al, 1974), transport of oxygen in mammalian and other respiratory systems (Singh et al, 2010). Few Schiff's bases are prepared, characterized and determined the kinetic parameters of chitosan with salicylaldehyde (Guinesi and Cavalheiro, 2006), trans 1,2-cyclohexadiamine with salicylaldehyde (Aranha et al, 2007) and 4-aminoantipyridine with 2-aminophenol (Mohamed et al, 2009).…”